Bondline - User contributions [en]

Disassembly

2014-02-06T20:11:15Z

Bob Steward: Spelling correction

A request on the GG for information on how to remove your plane from a non-airport landing site by disassembling it enough to fit it on a trailer or flat bed wrecker lead to this article and the check lists below.

[[Image:2-place_no_wings.jpg]][[Image:4placewingsremoved.jpg]]

== Removing the wings (4 place) ==

# Buy a bunch of Zip-Locks bags and a Sharpie to keep track of all your hardware as you remove it.
# Remove the wing tips.
# If you're going to be transporting the wings flat, remove the pitot tube and tie-down rings.
# Remove the aileron to control horn bolt at the center of the fuselage under the back seat (two separate through-bolts on the 4-place).
# Remove the bolts on the outer aileron bearing bracket and aft spar. Hold up the outer aileron to keep it from falling.
# Slide aileron assembly with counterweight and bearing bracket out. May have to rotate it slowly to break the friction on the inner control horn; go slowly.
# Lower flaps to access to the nut on the flap drive arm; remove nut and washer. Alternate method: leave arm attached and move flaps up and down as need to get access to the bolts in the following step. Your goal is to get access to the flap drive clamp bolts, an aluminum block that fits around the large torque tube, in the outboard corners of the "hell hole" under the back seat.
# Back off (''do not remove'') the two "set" bolts on each flap drive torque tube clamp and loosen the pinch bolt at the inboard end of the tube. '''The 2 bolts that pin the clamp to the torque tube need only be backed out 3-4 turns, and will sometimes take the threads out with them if backed completely out.''' As per the above instruction, you may need to move the flaps up and down a couple times to get access to all the bolts. Be patient.
# Pull the torque tube out of the clamp block and first (inner) bearing bracket on the wing.
# Remove outer flap/inner aileron bearing bracket (can be a pain to get to the bolt heads. Again, ''be patient'').
# Slide flap out, some care is needed to break loose the RTV at the inboard end. Repeat flap removal on the opposite side.
# Remove sump covers from under wing root.
# Disconnect pitot line on left wing sump area. The (probably clear) plastic hose that couples the two 1/4" aluminum tubes is probably hard, so just cut the plastic line and replace with a new part (it's cheap) later.
# Disconnect the electrical (pitot, strobes, nav lights, stall warning switch, etc.) in the sump area, both sides. If any wires do not have a connector in that area (for example, if someone added strobes), cuss at your A&P and snip the wire cleanly; you'll add a connector upon re-assembly. If more than one wire needs to be cut, cuss out your A&P some more and clearly mark each wire (colored tape, label maker, etc) so you'll know which is which on re-assembly.
# Drain the fuel from wing root sumps by removing the drain valve and using a large diameter funnel. 8-10" is about as small as you can use and not lose fuel on the ground due to any breeze and to the run-off from the edges of the sump, since the threaded boss is flush with the surface. '''Alternate de-fueling option:''' buy one of those simple "shaker siphons" (example:http://www.boatshowproducts.com/super-siphon-hose) and use that to siphon out the vast majority of the fuel prior to pulling the sump drain. Makes for a lot less mess.
# Do we need to state the obvious about '''using extreme care when de-fueling'''? The stuff is flammable, you know...
# Before you proceed further, here's a '''general AN-type fittings note!''' You '''must not''' allow the bulkhead (or any) fitting in the wing (or lines) to rotate while you loosen the line nuts, so have the appropriate size wrench handy and HOLD that bulkhead nut against the rib (or AN elbow) with an appropriate backup wrench and turn only the line nut. '''Do not''' rely on using leverage on lines or fittings to loosen these AN nuts, '''always''' use backup wrenches. These lines and fittings are not cheap!
# Loosen the fuel lines AT THE SUMP and remove the small vent line (some vent lines have a rubber connection between the wing and the sump line, some have a hard aluminum line with a flare at both ends).
# '''26-gallon "long range" tanks''': there are two round access covers just fore and aft of the sump cover area that give you access to the areas where these fuel lines go ('''not''' the ones outboard of the wing root seal); remove these two covers each side. Once they are removed you'll see two AN fuel line elbows, one each fore and aft, both sides; remove these elbows and the hard lines that go from these elbows to the fuel sump.
# '''19 gallon tanks''': DO NOT take the 19 gallon tank inspection panel screws out! The first bay on the standard tanks is WET! You will access these fittings as you are removing the wings; see notes below.
# Remove the wing panel to center spar bolts (2 each wing, exactly on the fore and aft centerline of the spar). Judicious use of 3/8-drive socket extensions and swivels may be required; six-point sockets are strongly recommended.
# Position one person at the inboard leading edge, one at the inboard trailing edge and one at the wing tip. The person at the wing tip will lift UP slightly to unbind the wing from the weight pulling down on the socket joint of the wing spar to center section. The two inboard people CAREFULLY rotate the wing around the spar up and down only 1/4"-1/2" at a time - not too much, just a little! - while the person at the tip pulls OUT.
# '''19 gallon tanks''': You will need to move the wing out from the wing root '''only''' an inch or so, to allow access to the AN fuel line fittings at the inboard rib on the 19-gallon tanks. Once it's out an inch you'll have access; remove this line.
# '''26-gallon "long range" tanks''': as long as you removed the fuel lines and elbows as described above, you can remove the wing without removing these lines that go to the tanks. However, take care to ensure you do not damage these extended lines as you remove the wing, they are coming out of a small hole and can get caught.
# '''All airplanes''': remember you have wires and hoses that may extend into the wing root. Do not rotate the wing so much as to damage these.
# With fuel lines loose from wing rock it as before - just slightly! - nose up and down while pulling outboard. The socket joint is just over 1 foot long, so go slow when you get beyond 8-10" away from the wing root. Pull wing panel off and set on a padded surface.
# Grab your favorite beverage and marvel at what you just accomplished. Then get back to work and get that airplane back in the sky!

There are some differences in removing the 2 place wings. Mostly because of the differences in the fuel system.

[[Image:4placetrailer.jpg]]

== Removing the Horizontal Stabilizer and Elevators ==

There are 2 methods, both explained below. Remove the entire assembly with elevators installed, or remove elevators individually, then the Stabilizer by itself. Much of it is in common, differences will be noted, removal of the entire assembly is explained first.

# Remove tailcone plastic under rudder (8 sheet metal screws plus the position light wiring which unplugs at aft bulkhead)
# Remove forward facing HS "fillets" at inboard ends of HS and fuselage sides. (4 screws, one upper and one lower each side, slide forward off clips)
# Remove 8 AN4 (7/16" head) bolts on HS forward attachment (4 each side), exposed when fillets were removed.
# Remove ELT covers on both sides
# Remove cotter pins and clevis bolts from elevator control cables.
# Remove 2 clamp bolts (AN4 - 7/16" heads) on elevator control horns and collect spacers that held the control horns apart.
# Remove cotter pin, nut and bolt at the control horn pivot
# Remove the 2 AN3 (3/16" head) bolts that clamp the trim drive to the jackscrew (under the HS and Elevators, that threaded thingy that comes out of the aft bulkhead). Secure dangling arms so they don't get fouled by other work, and DO NOT disturb the relationship of the threaded trim drive to the barrel nut and trim arms that are now loose. This is a RIGGING component, and quite easy to screw up, if you don't secure it now, so that it can't move.

== For removal of elevators separately skip down to that section now ==

# Remove the control horn to elevator torque tube bolts (Close tolerance AN174 bolts -- 7/16" heads), and carefully wiggle the control horns outboard ~1/4" on each side.
# Using an extension (preferably 1/4" drive), back the upper and lower elevator stop bolts out of the aft bulkhead. They have Jam nuts on them to prevent rotation, which may require untorquing first, but usually the bolts can be unscrewed with the jam nuts left alone. For ease of re-assembly, disturb the jam nuts a little as possible and mark the bolts as "upper" and "lower", so that they can be spun back in to almost exact location, as these set the up and down limits of the elevators and are important rigging components.

Skip down to Removing HS if you are leaving the elevators installed.

== Removing the Elevators separately ==
Having accomplished the steps above, begin here:
# Remove safety wire and bolts that hold the trim "yoke" to the 2 elevators.
# Remove the cotter pins, nuts and clevis bolts that attach the yoke to the individual trim arms.
# Remove yoke and wrap safety wire through each hole where it was bolted to the elevators (forward end) to contain the spacer, etc.
# On each elevator locate the 2 outboard bearing supports (lift elevator up and look in the bottom forward edge for "pockets) with a bolt and some safety wire), and remove safety wire, bolts and washers. Note that elevator will FALL when last bolt is removed, so have a helper support the elevator with the trailing edge UP so you can work on the bolts.
# Slide elevator half straight aft, off of the bearing supports. Repeat last 2 steps for other side.
# Using an extension (preferably 1/4" drive), back the upper and lower elevator stop bolts out of the aft bulkhead. They have Jam nuts on them to prevent rotation, which may require untorquing first, but usually the bolts can be unscrewed with the jam nuts left alone. For ease of re-assembly, disturb the jam nuts a little as possible and mark the bolts as "upper" and "lower", so that they can be spun back in to almost exact location, as these set the up and down limits of the elevators and are important rigging components.
== Removing HS ==

# Reaching inside the ELT covers through the larger hole in the ELT "shelf", if ELT is installed under vertical fin, put a 7/16" wrench or, using a long extension and 7/16" socket, locate the 2 nuts that secure the stiffener rod from the aft bulkhead to the HS forward spar carry through, and hold them as the AN4 (7/16" head) bolts on the pilot's side of the elevator center pivot bearing bracket are removed. (This is the "Trick" to getting the HS off, that all novices can't find, and even a few experienced removers have forgotten when in a hurry. <cough>)
# Remove the 4 AN6 (9/16" head) bolts on the aft spar, remembering that as the last one is pulled, the HS and elevators will come free, and this is NOT a one person job. Support the HS/Elevators at both ends while the last bolt is removed, and slide it straight back, avoiding any side to side or tilting, that can bind the HS against the fuselage and scratch the paint.
# Set on padded surface. Consider taping elevator tips to HS if you left the elevators installed. This makes it easier to move, store and re-hang HS in the future.

Windshields (2 & 4 place) and Canopy (2 place)

2014-01-13T22:23:43Z

Bob Steward: /* Bonding the Bow to the Plexi */

== Introduction ==

Windshield replacement in all models and Canopy replacement (2 place)

'''Mechanical Difficulty:''' [[Image:Wrench3.jpg]] '''-''' [[Image:Wrench4.jpg]]

'''Unlike side window replacement, windshields may NOT be signed off for return to service by the owner/pilot. You will have to have someone with an Airframe rating to supervise and make the log entry approving it for return to service.'''

Only the most intrepid (and some would say foolhardy) owners would attempt to install their own windshield or AA-1x canopy without the assistance of someone with experience doing Grumman bonded windshield replacement. No one step is particularly difficult, but the process does not allow for much error, and the cost of failure is high ($400-$500 in parts and shipping) for another windshield if you crack it drilling holes, or bond it in crooked such that the canopy won't seal tightly, etc.

Most of the steps for the windshield and canopy are very similar, especially the removal of the bow, the cleaning and then re-bonding to the new plexi. Only areas with significant differences will be shown under the "Canopy" heading. All the rest of the explanation can be applied to either part. It is not necessary to remove the windshield to work on the canopy or to remove the canopy to work on the windshield, however both tasks are explained below.

== Unbolting the windshield ==

There are 2 AN3 bolts on the lower end of each side of the windshield bow. To access them, remove the plastic trim and the screws holding the forward edge of the upholstery on the cabin sides. The plastic trim is held in by a several #4 sheet metal screws. On the AA-5x series the pilot's side has a rocker switch and a map light on a flexible stalk to be removed. Many AA-1x and most AA-5x have the compass located on the windshield bow. The wiring follows the forward edge of the windshield bow down the right side. The ground wire is attached with a screw to the honeycomb, and the power wire is crimped in the same connector as the panel light lead and must be cut off. A new connector can be installed later to allow the bow to be removed without cutting wires.

After accessing the AN3 bolts at the bottom of the bow, there are 7 screws around the lower edge of the windshield. 2 screws on each side of the fuselage, one at the bow and one a few inches forward, and 3 screws at the forward edge of the windshield. It may be easier to remove the 3 forward screws if the glareshield cover on top of the instruments is removed.

[[Image:LHbolts.jpg]] [[Image:Fscrews.jpg]]

The bolts on the right side are the same, but less wiring to deal with.

== Unbolting the Canopy ==

The canopy comes off the sliding rails with the removal of the bottom row of screws. A second person to help support and lift the canopy is strongly suggested.

After all the bottom row of screws is out, the canopy can be lifted straight up and off of the plane. This ought to be done by at least 2 people, and 3 would offer an additional level of safety. With a helper on the opposite wing root, lift the canopy straight up, taking care not to scratch the quarter windows with the sharp corners at the aft edge of the canopy. Once the canopy is above the turtledeck height, carefully hand it over to one person on the wing root. The other person then gets off the wing and comes to the trailing edge of the wing so that the person holding the canopy can hand it down.

== Removing the Windshield ==

At this point all the wiring is loose, all the screws are out, and all that is holding the windshield in place is the adhesion of the old sealant around the forward edge (which on some planes has incorrectly been replaced with RTV silicone by those that did not read the maintenance manual), and the spring tension of the aluminum bow. As needed, insert a thin bladed putty knife into the plexi-aluminum joint around the front of the windshield to pop the windshield loose. Push inward on the bow and attempt to slide the legs of the bow upward and aft to lift the windshield clear of the fuselage. Some more scraping with the putty knife may be needed as additional areas of adhesion are discovered. Lift the windshield and bow out of the plane and hand the complete assembly to a helper on the ground.

== Removing the Bow ==

Early models (69-73) have multiple holes drilled through the plexi and the aluminum bow, and screws to hold the assembly together. It is a simple matter to remove the screws and clean and residue of the gasket material from the bow.

Late models (74 on) have a bonded bow and plexi, with some later production planes having 2 screws, one on either side of the latch assembly to help resist the shearing force caused by the latch. On the bonded assemblies it is assumed that the windshield is not being reused, so cutting the bonding with a variety of methods is possible. A piece of safety wire wrapped around some wooden handles can be used to cut the RTV bonding. A putty knife can be used to slice the bonding. A single edged razor blade can be worked around the aft face of the bow to slice through the sealant about 1/2 way across the bow. In many cases the bonding may be failing and large sections of the bow may already be coming loose.

Tip: In the case where the RTV bonding is failing and the windshield or canopy is still in good shape, care to separate the remaining bond is needed to avoid damaging the plexi. The razor blade or putty knife methods have worked well for me in the past. Usually, once the RTV is starting to let go, it all comes apart pretty easy. Masking the inside if the windshield (or canopy), with some aluminum tape or a couple layers of duct tape from the bond line towards the part that you look through, would be a good idea. You may find that a sharp single edged razor blade held perpendicular to the inside of the plexi and used as a scraper can remove most all the old bonding material. I've followed this with a "DA" or random orbit sander and some 400 grit paper to remove scratch marks and the last of the RTV. The fogged apperance of the plexi will diminish sharply if the DOW 1205 primer is applied and the plastic allowed to soften slightly, as recommended for the original RTV bonding method.

== Removing the Canopy Skirt ==

At the aft edge of the plexi, there is an alumiunum skirt that completes the distance from the aft edge of the canopy to the turtle deck. A row of screws secures it to the plexi and the aft canopy bow. Removing the screws and taking the lock cylinder off the pilot's side will free the plexi and the aft bow from the skirt.

== Cleaning the Bow ==

Once the bow is released, the next step is to thoroughly clean the remaining bonding agent off the aluminum. Scraping with a putty knife works well. Sometimes small areas may need to be scraped with a single edge razor blade to remove particularly well attached bonding material. Sanding until smooth, followed by a solvent wipe to remove the oil from finger prints is a good final cleaning step.

== Checking the Bow ==

Now is a good time to check that the bow is straight. Its not uncommon for the windshield or forward canopy bow to not lay flat, and this must be addressed before any trimming or bonding takes place.

== Bonding the Bow to the Plexi ==

The OEM factory bonding and the instructions from LP Aero until recently were all based on a Silicone Rubber "RTV" bond. The instructions from LP Aero described the materials as Dow Corning 732 RTV and Dow Corning 1200 and 1205 primers. This method was used successfully for more than 30 years and resulted in excellent bonding, if the primers were used and care was taken to prevent contamination of the bond area. Because the smallest quantity the primers are sold in is 13 oz. and they require a Hazmat charge to ship them, it could cost $40 for the two primers and another $20 in Hazmat charges, and all that is needed is about 1 oz. of each primer. Because of these costs and inconveniences, another bonding process has begun to replace the RTV. Recently LP Aero changed its instructions, and a new poly-sulfide based bonding material was recommended. This material is "Pro-seal" fuel tank sealant and is compatible with MIL-S-8802. Its available in several brands, but its vitally important that you use the "Adhesion Promoter" AC-137 from Advanced Chemistry and Technology, or its equivalent in the brand of sealant you use. (3M purchased AC&T a couple years ago, so now the Poly-Sulfide bonding system and Adhesion Promoter are all now 3M branded.)

== On the Plane or On the Bench? ==

The bow can be clamped in place with the plexi and bow jigged on the plane, or it can be "bench bonded" and then installed on the plane. Both methods have their advantages and also some drawbacks. In the on plane installation you will need at least 12-15 2-3" C-clamps to apply the pressure that keeps the plexi aligned with the bow during the cure of the adhesive. With the bench method, you'll need a table large enough for the entire bow to lay flat and some sort of surface that can be drilled and screws installed to provide the needed clamping action.

[[Image:Benchbond.jpg]] [[Image:RTVbond.jpg]]

The windshields are slightly oversize to accommodate production tolerances of the airframes. This means that the excess must be trimmed. The question is how much is excess and exactly WHERE it should be trimmed. Windshields that are bench bonded typically have the forward edge trimmed after the bonding is cured. Canopies that are bench bonded have the aft edge trimmed, and the bottom edges along the canopy rails also need to be trimmed. The problem begins with the lack of rigidity of the plexi. Trying to hold it in place at one location will cause it to spring loose on the opposite side. This is one of the reasons that first time installers have such a hard time doing a good job. They just can't get that big floppy piece of plexi to lay down so they can figure out where to trim and mark the locations.

To bench bond a canopy or windshield bow, one should start with the bow out of the plane and checked for flatness. Some metal work to make it lay down flat on the face of the angle that would be vertical when installed, may be needed. The exact distance between the mounting holes at the bottom of the bow is also needed, so that you can measure that distance out on your table. Marking the hole centers and then securing the bow to the table (#6x1" drywall screws are very handy for this) lets you measure the bow to find the center. A mark on the table is a good way to keep that location visible. You will be cleaning the bow and treating it with primer and covering it with bonding agent, so any mark made on the bow will be gone.

Measure the plexi and mark the center of the plexi with a china marker or with a permanent marker on the "spray lat" protective covering on the outside, because you will remove the inner covering when bonding, and your mark will be gone with it! Now you can position the plexi on the table over the bow and line up the center marks. The plexi should end at the same distance on both legs of the bow, as a quick check that you have accurate center marks. A mark on the table at each lower corner of the plexi will be helpful later in assuring that the plexi did not slide while clamping it.

The inner spray lat is removed, or at least the first few inches. The plexi is laid over the bow, and the edge of the bonding is masked with masking tape or duct tape. Make sure that you have burnished the edge down well, as the primer and bonding agent can wick under the tape edge and leave your bond line uneven.

Lightly sand the area to be bonded. 320-400 grit paper is a good choice. A wipe with Naptha on a clean cloth will remove the sanding dust and your finger prints along with the oils from your skin that would contaminate the bond. The bow is prepared with a solvent wipe (MEK is a strong degreaser that leaves no residue when it flashes off), and the primer is appied per the instructions that come with it. If using the 732 RTV and the 1200 and 1205 primer system, 1200 is used on the metal bow, and 1205 is used on the plexi. If using the Pro-Seal method, the AC-137 adhesion promoter is used on both the metal and the plexi.

The plexi is prepared with the primer, and the bonding material is applied to the bow and trowelled so an even thickness of about 1/8" thick. The plexi is placed over the bow and lined up with the center mark and the two end marks previously located. Because of the thickness of the sealant, the two end marks will not quite match the plexi, but the distance should be evenly split between them. It can help to have someone hold the plexi sides out just a bit (away from the cleaned and primed area) so that the plexi doesn't scrape off the bonding agent as it is being slid into position.

Secure the windshield by clamping the bonded area. The wood blocks and drywall screws shown in the picture work very well on a bench that can have screw holes placed in it. They are easy to make and very inexpensive.

Start in the middle and work out to both corners evenly. Watch that you have squeezed the excess sealant out of the bonded area, but don't press so hard as to force ALL the sealant out. You should stop clamping before you see the aluminum bow pressed against the inside of the plexi. Wipe the excess sealant off the inside of the bow/windshield joint. It is much easier to make a nice finished edge now and have the clean up work complete while the bonding agent is still soft.

Wait overnight, or longer if the temperature is not above 70 degrees F.

'''TIP: An electric blanket laid over the outside of the bond and draped up over the plexi can be a big help with the temperatures are low overnight.'''

Check the cure of the bond by testing an edge of the sealant in an area that you can't see after the plexi is installed. It should be firm and rubbery, and not at all sticky. If not cured enough keep it warm and wait another 6-12 hours. You really can not rush the curing, and releasing the clamps before the bonding is done will contribute to the bond coming apart.

== The On the Plane Method (Under Construction) ==

Windshields (2 & 4 place) and Canopy (2 place)

2014-01-13T22:20:16Z

Bob Steward: Fixed Adhesion Promoter part number

== Introduction ==

Windshield replacement in all models and Canopy replacement (2 place)

'''Mechanical Difficulty:''' [[Image:Wrench3.jpg]] '''-''' [[Image:Wrench4.jpg]]

'''Unlike side window replacement, windshields may NOT be signed off for return to service by the owner/pilot. You will have to have someone with an Airframe rating to supervise and make the log entry approving it for return to service.'''

Only the most intrepid (and some would say foolhardy) owners would attempt to install their own windshield or AA-1x canopy without the assistance of someone with experience doing Grumman bonded windshield replacement. No one step is particularly difficult, but the process does not allow for much error, and the cost of failure is high ($400-$500 in parts and shipping) for another windshield if you crack it drilling holes, or bond it in crooked such that the canopy won't seal tightly, etc.

Most of the steps for the windshield and canopy are very similar, especially the removal of the bow, the cleaning and then re-bonding to the new plexi. Only areas with significant differences will be shown under the "Canopy" heading. All the rest of the explanation can be applied to either part. It is not necessary to remove the windshield to work on the canopy or to remove the canopy to work on the windshield, however both tasks are explained below.

== Unbolting the windshield ==

There are 2 AN3 bolts on the lower end of each side of the windshield bow. To access them, remove the plastic trim and the screws holding the forward edge of the upholstery on the cabin sides. The plastic trim is held in by a several #4 sheet metal screws. On the AA-5x series the pilot's side has a rocker switch and a map light on a flexible stalk to be removed. Many AA-1x and most AA-5x have the compass located on the windshield bow. The wiring follows the forward edge of the windshield bow down the right side. The ground wire is attached with a screw to the honeycomb, and the power wire is crimped in the same connector as the panel light lead and must be cut off. A new connector can be installed later to allow the bow to be removed without cutting wires.

After accessing the AN3 bolts at the bottom of the bow, there are 7 screws around the lower edge of the windshield. 2 screws on each side of the fuselage, one at the bow and one a few inches forward, and 3 screws at the forward edge of the windshield. It may be easier to remove the 3 forward screws if the glareshield cover on top of the instruments is removed.

[[Image:LHbolts.jpg]] [[Image:Fscrews.jpg]]

The bolts on the right side are the same, but less wiring to deal with.

== Unbolting the Canopy ==

The canopy comes off the sliding rails with the removal of the bottom row of screws. A second person to help support and lift the canopy is strongly suggested.

After all the bottom row of screws is out, the canopy can be lifted straight up and off of the plane. This ought to be done by at least 2 people, and 3 would offer an additional level of safety. With a helper on the opposite wing root, lift the canopy straight up, taking care not to scratch the quarter windows with the sharp corners at the aft edge of the canopy. Once the canopy is above the turtledeck height, carefully hand it over to one person on the wing root. The other person then gets off the wing and comes to the trailing edge of the wing so that the person holding the canopy can hand it down.

== Removing the Windshield ==

At this point all the wiring is loose, all the screws are out, and all that is holding the windshield in place is the adhesion of the old sealant around the forward edge (which on some planes has incorrectly been replaced with RTV silicone by those that did not read the maintenance manual), and the spring tension of the aluminum bow. As needed, insert a thin bladed putty knife into the plexi-aluminum joint around the front of the windshield to pop the windshield loose. Push inward on the bow and attempt to slide the legs of the bow upward and aft to lift the windshield clear of the fuselage. Some more scraping with the putty knife may be needed as additional areas of adhesion are discovered. Lift the windshield and bow out of the plane and hand the complete assembly to a helper on the ground.

== Removing the Bow ==

Early models (69-73) have multiple holes drilled through the plexi and the aluminum bow, and screws to hold the assembly together. It is a simple matter to remove the screws and clean and residue of the gasket material from the bow.

Late models (74 on) have a bonded bow and plexi, with some later production planes having 2 screws, one on either side of the latch assembly to help resist the shearing force caused by the latch. On the bonded assemblies it is assumed that the windshield is not being reused, so cutting the bonding with a variety of methods is possible. A piece of safety wire wrapped around some wooden handles can be used to cut the RTV bonding. A putty knife can be used to slice the bonding. A single edged razor blade can be worked around the aft face of the bow to slice through the sealant about 1/2 way across the bow. In many cases the bonding may be failing and large sections of the bow may already be coming loose.

Tip: In the case where the RTV bonding is failing and the windshield or canopy is still in good shape, care to separate the remaining bond is needed to avoid damaging the plexi. The razor blade or putty knife methods have worked well for me in the past. Usually, once the RTV is starting to let go, it all comes apart pretty easy. Masking the inside if the windshield (or canopy), with some aluminum tape or a couple layers of duct tape from the bond line towards the part that you look through, would be a good idea. You may find that a sharp single edged razor blade held perpendicular to the inside of the plexi and used as a scraper can remove most all the old bonding material. I've followed this with a "DA" or random orbit sander and some 400 grit paper to remove scratch marks and the last of the RTV. The fogged apperance of the plexi will diminish sharply if the DOW 1205 primer is applied and the plastic allowed to soften slightly, as recommended for the original RTV bonding method.

== Removing the Canopy Skirt ==

At the aft edge of the plexi, there is an alumiunum skirt that completes the distance from the aft edge of the canopy to the turtle deck. A row of screws secures it to the plexi and the aft canopy bow. Removing the screws and taking the lock cylinder off the pilot's side will free the plexi and the aft bow from the skirt.

== Cleaning the Bow ==

Once the bow is released, the next step is to thoroughly clean the remaining bonding agent off the aluminum. Scraping with a putty knife works well. Sometimes small areas may need to be scraped with a single edge razor blade to remove particularly well attached bonding material. Sanding until smooth, followed by a solvent wipe to remove the oil from finger prints is a good final cleaning step.

== Checking the Bow ==

Now is a good time to check that the bow is straight. Its not uncommon for the windshield or forward canopy bow to not lay flat, and this must be addressed before any trimming or bonding takes place.

== Bonding the Bow to the Plexi ==

The OEM factory bonding and the instructions from LP Aero until recently were all based on a Silicone Rubber "RTV" bond. The instructions from LP Aero described the materials as Dow Corning 732 RTV and Dow Corning 1200 and 1205 primers. This method was used successfully for more than 30 years and resulted in excellent bonding, if the primers were used and care was taken to prevent contamination of the bond area. Because the smallest quantity the primers are sold in is 13 oz. and they require a Hazmat charge to ship them, it could cost $40 for the two primers and another $20 in Hazmat charges, and all that is needed is about 1 oz. of each primer. Because of these costs and inconveniences, another bonding process has begun to replace the RTV. Recently LP Aero changed its instructions, and a new poly-sulfide based bonding material was recommended. This material is "Pro-seal" fuel tank sealant and is compatible with MIL-S-8802. Its available in several brands, but its vitally important that you use the "Adhesion Promoter" AC-251 from Advanced Chemistry and Technology, or its equivalent in the brand of sealant you use.

== On the Plane or On the Bench? ==

The bow can be clamped in place with the plexi and bow jigged on the plane, or it can be "bench bonded" and then installed on the plane. Both methods have their advantages and also some drawbacks. In the on plane installation you will need at least 12-15 2-3" C-clamps to apply the pressure that keeps the plexi aligned with the bow during the cure of the adhesive. With the bench method, you'll need a table large enough for the entire bow to lay flat and some sort of surface that can be drilled and screws installed to provide the needed clamping action.

[[Image:Benchbond.jpg]] [[Image:RTVbond.jpg]]

The windshields are slightly oversize to accommodate production tolerances of the airframes. This means that the excess must be trimmed. The question is how much is excess and exactly WHERE it should be trimmed. Windshields that are bench bonded typically have the forward edge trimmed after the bonding is cured. Canopies that are bench bonded have the aft edge trimmed, and the bottom edges along the canopy rails also need to be trimmed. The problem begins with the lack of rigidity of the plexi. Trying to hold it in place at one location will cause it to spring loose on the opposite side. This is one of the reasons that first time installers have such a hard time doing a good job. They just can't get that big floppy piece of plexi to lay down so they can figure out where to trim and mark the locations.

To bench bond a canopy or windshield bow, one should start with the bow out of the plane and checked for flatness. Some metal work to make it lay down flat on the face of the angle that would be vertical when installed, may be needed. The exact distance between the mounting holes at the bottom of the bow is also needed, so that you can measure that distance out on your table. Marking the hole centers and then securing the bow to the table (#6x1" drywall screws are very handy for this) lets you measure the bow to find the center. A mark on the table is a good way to keep that location visible. You will be cleaning the bow and treating it with primer and covering it with bonding agent, so any mark made on the bow will be gone.

Measure the plexi and mark the center of the plexi with a china marker or with a permanent marker on the "spray lat" protective covering on the outside, because you will remove the inner covering when bonding, and your mark will be gone with it! Now you can position the plexi on the table over the bow and line up the center marks. The plexi should end at the same distance on both legs of the bow, as a quick check that you have accurate center marks. A mark on the table at each lower corner of the plexi will be helpful later in assuring that the plexi did not slide while clamping it.

The inner spray lat is removed, or at least the first few inches. The plexi is laid over the bow, and the edge of the bonding is masked with masking tape or duct tape. Make sure that you have burnished the edge down well, as the primer and bonding agent can wick under the tape edge and leave your bond line uneven.

Lightly sand the area to be bonded. 320-400 grit paper is a good choice. A wipe with Naptha on a clean cloth will remove the sanding dust and your finger prints along with the oils from your skin that would contaminate the bond. The bow is prepared with a solvent wipe (MEK is a strong degreaser that leaves no residue when it flashes off), and the primer is appied per the instructions that come with it. If using the 732 RTV and the 1200 and 1205 primer system, 1200 is used on the metal bow, and 1205 is used on the plexi. If using the Pro-Seal method, the AC-137 adhesion promoter is used on both the metal and the plexi.

The plexi is prepared with the primer, and the bonding material is applied to the bow and trowelled so an even thickness of about 1/8" thick. The plexi is placed over the bow and lined up with the center mark and the two end marks previously located. Because of the thickness of the sealant, the two end marks will not quite match the plexi, but the distance should be evenly split between them. It can help to have someone hold the plexi sides out just a bit (away from the cleaned and primed area) so that the plexi doesn't scrape off the bonding agent as it is being slid into position.

Secure the windshield by clamping the bonded area. The wood blocks and drywall screws shown in the picture work very well on a bench that can have screw holes placed in it. They are easy to make and very inexpensive.

Start in the middle and work out to both corners evenly. Watch that you have squeezed the excess sealant out of the bonded area, but don't press so hard as to force ALL the sealant out. You should stop clamping before you see the aluminum bow pressed against the inside of the plexi. Wipe the excess sealant off the inside of the bow/windshield joint. It is much easier to make a nice finished edge now and have the clean up work complete while the bonding agent is still soft.

Wait overnight, or longer if the temperature is not above 70 degrees F.

'''TIP: An electric blanket laid over the outside of the bond and draped up over the plexi can be a big help with the temperatures are low overnight.'''

Check the cure of the bond by testing an edge of the sealant in an area that you can't see after the plexi is installed. It should be firm and rubbery, and not at all sticky. If not cured enough keep it warm and wait another 6-12 hours. You really can not rush the curing, and releasing the clamps before the bonding is done will contribute to the bond coming apart.

== The On the Plane Method (Under Construction) ==

Valve Wobble Testing

2013-08-12T17:14:33Z

Bob Steward: Added link to ACS valve wobble tool

Everything you ever wanted to know about the dreaded [http://www.lycoming.com/Portals/0/techpublications/servicebulletins/SB%20388C%20%2811-22-2004%29/Procedure%20to%20Determine%20Exhaust%20Value%20and%20Guide%20Condition.pdf Valve Wobble Test...] straight from [http://www.lycoming.com Mother Lycoming].

The purpose of the Valve Wobble Test is to check for the proper clearance between the exhaust valve and the exhaust valve guide. Too little clearance, and the valve may stick in the guide and cause a loss of power or even a mechanical failure such as a broken valve or bent pushrod. Too much clearance leads to micro-fractures in the valve stem due to the valve seating off center on the tapered seat in the cylinder head, and wedging the head slightly crooked to match the seat taper. Repeated every combustion cycle at 1300-1400 degrees F, the valve stem eventually breaks and the head falls into the cylinder and is violently struck by the piston over and over. Tremendous damage results and the debris is often swept into other cylinders and causes more damage and power loss.

Needless to say, both possible failure modes, sticking valves from not enough clearance, or breaking valves from too much clearance are to be avoided.

The sticking valve is caused by a build up of deposits in the guide or on the valve stem. These are combustion deposits and cooked oil. Excessive CHT can encourage the oil that lubricates the guide to "coke" and turn to a baked on carbon layer. It is good practice to avoid CHTs over 400 degrees F. The stock baffling will do this if kept in good shape. After 30+ years, there is very little original baffle seal left in the fleet, and of that which has been replaced, it is quite common to see very poor installation, and often the wrong material used.

This is the Lycoming tool recommended by the SB-388C document...
[[Image:Lycoming-tool.JPG]]

A similar tool is available from [http://www.aircraftspruce.com/catalog/topages/valvewobble.php?clickkey=240360 Aircraft Spruce], but works slightly differently. The Lycoming tool depresses the exhaust valve spring when installed, the Aircraft Spruce one does not. The above tool is usually modified to use a dial indicator to get direct readings. As shown above, the small screw on the right is adjusted to be close to the valve stem extension and a feeler gauge is used to get readings.

Valve Wobble Testing

2013-08-12T17:11:58Z

Bob Steward: Fixed dead link to Lycoming Service Bulletin 388C

Everything you ever wanted to know about the dreaded [http://www.lycoming.com/Portals/0/techpublications/servicebulletins/SB%20388C%20%2811-22-2004%29/Procedure%20to%20Determine%20Exhaust%20Value%20and%20Guide%20Condition.pdf Valve Wobble Test...] straight from [http://www.lycoming.com Mother Lycoming].

The purpose of the Valve Wobble Test is to check for the proper clearance between the exhaust valve and the exhaust valve guide. Too little clearance, and the valve may stick in the guide and cause a loss of power or even a mechanical failure such as a broken valve or bent pushrod. Too much clearance leads to micro-fractures in the valve stem due to the valve seating off center on the tapered seat in the cylinder head, and wedging the head slightly crooked to match the seat taper. Repeated every combustion cycle at 1300-1400 degrees F, the valve stem eventually breaks and the head falls into the cylinder and is violently struck by the piston over and over. Tremendous damage results and the debris is often swept into other cylinders and causes more damage and power loss.

Needless to say, both possible failure modes, sticking valves from not enough clearance, or breaking valves from too much clearance are to be avoided.

The sticking valve is caused by a build up of deposits in the guide or on the valve stem. These are combustion deposits and cooked oil. Excessive CHT can encourage the oil that lubricates the guide to "coke" and turn to a baked on carbon layer. It is good practice to avoid CHTs over 400 degrees F. The stock baffling will do this if kept in good shape. After 30+ years, there is very little original baffle seal left in the fleet, and of that which has been replaced, it is quite common to see very poor installation, and often the wrong material used.

This is the Lycoming tool recommended by the SB-388C document...
[[Image:Lycoming-tool.JPG]]

A similar tool is available from Aircraft Spruce, but works slightly differently. The Lycoming tool depresses the exhaust valve spring when installed, the Aircraft Spruce one does not. The above tool is usually modified to use a dial indicator to get direct readings. As shown above, the small screw on the right is adjusted to be close to the valve stem extension and a feeler gauge is used to get readings.

Pre-Purchase Inspections

2013-08-12T17:08:47Z

Bob Steward: Fixed dead link to Lycoming Service Publication SI 1009AR

'''Mechanical Difficulty:''' [[Image:Wrench4.jpg]] (Not that you'd do your own inspection...)

There are as many different ideas on the proper scope and depth of a pre-purchase inspection as there are buyers. What makes that interesting is the expectations of those buyers, and how those expectations change after owning a plane for 11 months and having gone through the dreaded "first annual".

When is it a better time to discover the true condition of the plane, during the purchase process or after the money has changed hands and the plane has flown away? This is the reason it is suggested that a purchaser do a thorough pre-buy and do all that is reasonable to identify things that will later bite him in the wallet. What that means is a full annual inspection by the check list in the factory maintenance manual -- 13 pages for the AA-5x, a few less for the AA-1x.

"But it just had a fresh annual last month and has flown nearly no hours since then."

Perhaps, but who did the inspection, and did you get a copy of the signed, dated list of discrepancies?

Most planes sell because the owner is moving on. Sometimes it's to larger or smaller aircraft, but often it's away from aviation. So what did they tell the mechanic that performed the last annual? Probably something along the lines of: "I've got it listed in T-A-P, so don't spend any money on it that you don't have to." That is a pretty sobering thought when you know that you are going to take your family and friends up in your new plane just as soon as you can get it home.

Another factor that enters the discussion is that an "Annual Inspection" is just that, INSPECTION. As in LOOK at it. No repairs or service work are part of the inspection. And while it's true that the basic oil, filter, fluid levels and mag timing checks are regularly performed inconjunction with the inspection, that is just a convenience for the owner, since the plane is in the shop, they have it opened up, and most planes haven't had any service work since LAST year.

So if it's just been inspected, and no actual work was done to repair or improve the plane, just what did you get? Probably just bare minimum that the FAA requires for the plane to be legally operated. Certainly nothing that says there won't be any catastrophic failures or even minor items wearing or breaking on the very next flight. The plane was just "looked at". Maybe sort of a super pre-flight.

There have been many tales on the GG of woe and expense after purchasing a plane, and yet it seems that new buyers never learn, and the same mistakes are repeated again and again.

Lets go over some items that really ought to be checked during the pre-buy inspection on your intended purchase.

'''Paperwork'''

As strange as it may seem, the FAA is more focused on the paperwork than they are on the actual components. The reason for this is that if the paperwork is correct, then the physical components can be manipulated to create "Airworthiness". However if the paperwork is incorrect, then one can not make the plane "Airworthy" because the records that support the airworthiness are incomplete or inaccurate. The FAA takes this to the point that the DATA PLATE is the component they are most interested in, the rest of the airplane or engine are just parts which can be replaced as needed.

One must have the "AR(R)OW" paperwork for flight, and one must have an Airworthiness Certificate to determine that the aircraft in question was EVER in a condition to hold US Certification. Many planes were built and shipped overseas without ever having US paperwork, such as the ones that went directly to Canada that often are brought back to the US later. The price, especially considering the current exchange rates, may be very attractive, but one is left to PROVE to the FAA that the plane conforms to its Type Design and is therefore eligible to have an airworthiness certificate issued.

Logs are an important part of the paperwork. It's quite common to see planes for sale with some or all of the logs missing. This is a big red flag for the novice buyer. WHY are the logs missing? It could be that they were truly lost or destroyed. It's possible that the plane was a repossession or transferred in an estate at some time, and the logs were not available to the new owner. Or, a more nefarious possibility, they were intentionally kept back to avoid the documenting of repairs from some unreported accident! Perhaps there were even substandard repairs that included the use of undocumented parts or unapproved repair techniques. Lost logs require an even higher level of due diligence on the part of the inspector and purchaser.

'''Prop'''

Props have a TBO, just like engines. When is it due for an OH? Just consult the manufacturer's data for the prop in question. Most fixed pitch props are due for OH at engine OH, or at any time that they have wear or damage that exceeds the prop manufacturer's field dressing limits. Props are a "Class 1" appliance in FAA speak, and that means that they SHOULD have their own log. Most older planes do not, and this then makes it more difficult to establish the history of that prop. Models such as the McCauley prop used on the 70's production Tiger have AD mandated inspections every 200 hours. Without a dedicated prop log, where are those entries kept? Usually in the Airframe log, but what if a prop is bought used, did you get the airframe log entries showing past compliance with the AD and an accurate Total Time in Service? Better obtain a $5 prop log and transfer the available history to it, and begin logging inspections and maintenance from here forward.

'''Airframe'''

The single largest issue can probably be summed up in one word: '''Corrosion'''. As the fleet ages and time takes its toll on our light alloy airframes, oxidation is the number one problem that the fleet faces. The factory engineers never expected that we'd be flying significant portions of the fleet 35 years after production. They built the planes to last 10-15 years, and then expected that we'd scrap them and buy new ones. If aviation products didn't go up at over twice the rate of inflation, perhaps that would be the case. A new $30,000 Tiger? Sure, where do we mail the check?

Recently there seems to be a rash of planes with corrosion in the center spar. Not some light surface corrosion that might leave little pits in the spar tube, but full blown inter-granular corrosion that was raising bumps on the spar tube. This requires an expensive center spar and many hours of labor to replace it. Not all planes that have this sort of corrosion are "Florida" planes. The corrosion is severe enough on many planes that you have to ask WHEN in the last 20+ years of annual inspections was this overlooked, since it was quite obvious that it hadn't JUST popped up in the last few months.

'''Engine'''

Sellers are very fond of speaking highly of the good running of the engine, even though it's at or very near TBO. The implication, if not outright spoken statement is that TBO is just a "suggestion" and since THIS engine is running so well, has such fine compression and uses negligible oil between changes, that it's going to reach TBO and even go well beyond.

Of course this is total hog wash. No one can predict the future accurately by relying solely on past events. There are inspections such as the [http://www.bondline.org/index.php/Valve_Wobble_Testing SB388C "Valve Wobble" test] to check for hidden wear, and even invasive inspections like pulling cylinders to look at the cam and tappet bodies for spalling and corrosion to help determine if the engine is healthy. The [http://www.lycoming.com manufacturer (Lycoming)] has established a TBO based on field experience. What Lycoming has actually said is the criteria for determining what the REAL TBO for a particular engine should be is in [http://www.lycoming.com/Portals/0/techpublications/serviceinstructions/SI%201009AV%20%2807-08-2013%29/Recommended%20Time%20Between%20Overhaul%20Periods.pdf Lycoming SI 1009AR], and is based on 12 calendar years, OR 2000 hours, WHICH EVER COMES FIRST. (Or 2400 for O-235C and O-235L series in the AA-1x, under certain restrictions.)

Now, how do you feel about that 30 year old engine with "mid-time"? It's already 250% past it's factory recomended TBO! Busting the TBO by a few percent is one thing, by 2-1/2 times is another.

===The Inspection Process===

The inspection should be performed on the plane after the owner and the prospective purchaser have met, flown the plane, and negotiated a price for sale '''in its stated condition'''. The buyer should ask for and the seller should supply a complete list of every known squawk. This along with the Total Time of the airframe, engine and prop, the list of installed equipment and an accounting of the life limited components (spar tubes and wing attach shoulder bolts on AA-5x/AG-5B series, no life limited parts on the AA-1x series) comprise the documentation of the stated condition.

At this point, the price has been agreed to, the buyer wants to purchase the plane, and the seller is willing to sell and warrant the plane to be as represented.

The Pre-Purchase Inspection is now scheduled, with the intent of determining if the plane meets the stated condition by the seller. The purpose is not to pick the airplane to pieces and scare away the buyer or to find thousands of dollars worth of work the seller should pay for, rather it is to establish the true condition of the plane for comparison with the previously prepared squawk list. It's possible (and desireable) to do a PPI on a WRECKED plane. Again, the purpose is to bring to light the true condition of the plane, so that both parties are aware and accept the current condition as the basis for the sale.

It's quite common to surprise the owner with items that are worn, cracked, corroded, etc. And the seller and buyer make adjustments in the price to account for them, or the seller has them repaired to everyone's satisfaction, in order to bring the plane back to the previously stated condition, upon which the sale price was negotiated.

Pre-Purchase Inspections

2013-08-12T17:03:01Z

Bob Steward: Fixed dead link to Lycoming

'''Mechanical Difficulty:''' [[Image:Wrench4.jpg]] (Not that you'd do your own inspection...)

There are as many different ideas on the proper scope and depth of a pre-purchase inspection as there are buyers. What makes that interesting is the expectations of those buyers, and how those expectations change after owning a plane for 11 months and having gone through the dreaded "first annual".

When is it a better time to discover the true condition of the plane, during the purchase process or after the money has changed hands and the plane has flown away? This is the reason it is suggested that a purchaser do a thorough pre-buy and do all that is reasonable to identify things that will later bite him in the wallet. What that means is a full annual inspection by the check list in the factory maintenance manual -- 13 pages for the AA-5x, a few less for the AA-1x.

"But it just had a fresh annual last month and has flown nearly no hours since then."

Perhaps, but who did the inspection, and did you get a copy of the signed, dated list of discrepancies?

Most planes sell because the owner is moving on. Sometimes it's to larger or smaller aircraft, but often it's away from aviation. So what did they tell the mechanic that performed the last annual? Probably something along the lines of: "I've got it listed in T-A-P, so don't spend any money on it that you don't have to." That is a pretty sobering thought when you know that you are going to take your family and friends up in your new plane just as soon as you can get it home.

Another factor that enters the discussion is that an "Annual Inspection" is just that, INSPECTION. As in LOOK at it. No repairs or service work are part of the inspection. And while it's true that the basic oil, filter, fluid levels and mag timing checks are regularly performed inconjunction with the inspection, that is just a convenience for the owner, since the plane is in the shop, they have it opened up, and most planes haven't had any service work since LAST year.

So if it's just been inspected, and no actual work was done to repair or improve the plane, just what did you get? Probably just bare minimum that the FAA requires for the plane to be legally operated. Certainly nothing that says there won't be any catastrophic failures or even minor items wearing or breaking on the very next flight. The plane was just "looked at". Maybe sort of a super pre-flight.

There have been many tales on the GG of woe and expense after purchasing a plane, and yet it seems that new buyers never learn, and the same mistakes are repeated again and again.

Lets go over some items that really ought to be checked during the pre-buy inspection on your intended purchase.

'''Paperwork'''

As strange as it may seem, the FAA is more focused on the paperwork than they are on the actual components. The reason for this is that if the paperwork is correct, then the physical components can be manipulated to create "Airworthiness". However if the paperwork is incorrect, then one can not make the plane "Airworthy" because the records that support the airworthiness are incomplete or inaccurate. The FAA takes this to the point that the DATA PLATE is the component they are most interested in, the rest of the airplane or engine are just parts which can be replaced as needed.

One must have the "AR(R)OW" paperwork for flight, and one must have an Airworthiness Certificate to determine that the aircraft in question was EVER in a condition to hold US Certification. Many planes were built and shipped overseas without ever having US paperwork, such as the ones that went directly to Canada that often are brought back to the US later. The price, especially considering the current exchange rates, may be very attractive, but one is left to PROVE to the FAA that the plane conforms to its Type Design and is therefore eligible to have an airworthiness certificate issued.

Logs are an important part of the paperwork. It's quite common to see planes for sale with some or all of the logs missing. This is a big red flag for the novice buyer. WHY are the logs missing? It could be that they were truly lost or destroyed. It's possible that the plane was a repossession or transfered in an estate at some time, and the logs were not available to the new owner. Or, a more nefarious possibility, they were intentionally kept back to avoid the documenting of repairs from some unreported accident! Perhaps there were even substandard repairs that included the use of undocumented parts or unapproved repair techniques. Lost logs require an even higher level of due diligence on the part of the inspector and purchaser.

'''Prop'''

Props have a TBO, just like engines. When is it due for an OH? Just consult the manufacturer's data for the prop in question. Most fixed pitch props are due for OH at engine OH, or at any time that they have wear or damage that exceeds the prop manufacturer's field dressing limits. Props are a "Class 1" appliance in FAA speak, and that means that they SHOULD have their own log. Most older planes do not, and this then makes it more difficult to establish the history of that prop. Models such as the McCauley prop used on the 70's production Tiger have AD mandated inspections every 200 hours. Without a dedicated prop log, where are those entries kept? Usually in the Airframe log, but what if a prop is bought used, did you get the airframe log entries showing past compliance with the AD and an accurate Total Time in Service? Better obtain a $5 prop log and transfer the available history to it, and begin logging inspections and maintenance from here forward.

'''Airframe'''

The single largest issue can probably be summed up in one word: '''Corrosion'''. As the fleet ages and time takes its toll on our light alloy airframes, oxidation is the number one problem that the fleet faces. The factory engineers never expected that we'd be flying significant portions of the fleet 35 years after production. They built the planes to last 10-15 years, and then expected that we'd scrap them and buy new ones. If aviation products didn't go up at over twice the rate of inflation, perhaps that would be the case. A new $30,000 Tiger? Sure, where do we mail the check?

Recently there seems to be a rash of planes with corrosion in the center spar. Not some light surface corrosion that might leave little pits in the spar tube, but full blown inter-granular corrosion that was raising bumps on the spar tube. This requires an expensive center spar and many hours of labor to replace it. Not all planes that have this sort of corrosion are "Florida" planes. The corrosion is severe enough on many planes that you have to ask WHEN in the last 20+ years of annual inspections was this overlooked, since it was quite obvious that it hadn't JUST popped up in the last few months.

'''Engine'''

Sellers are very fond of speaking highly of the good running of the engine, even though it's at or very near TBO. The implication, if not outright spoken statement is that TBO is just a "suggestion" and since THIS engine is running so well, has such fine compression and uses negligible oil between changes, that it's going to reach TBO and even go well beyond.

Of course this is total hog wash. No one can predict the future accurately by relying solely on past events. There are inspections such as the [http://www.bondline.org/index.php/Valve_Wobble_Testing SB388C "Valve Wobble" test] to check for hidden wear, and even invasive inspections like pulling cylinders to look at the cam and tappet bodies for spalling and corrosion to help determine if the engine is healthy. The [http://www.lycoming.com manufacturer (Lycoming)] has established a TBO based on field experience. What Lycoming has actually said is the criteria for determining what the REAL TBO for a particular engine should be is in [http://www.lycoming.textron.com/support/publications/maintenancePublications/serviceInstructions/SI1009AR.pdf Lycoming SI 1009AR], and is based on 12 calendar years, OR 2000 hours, WHICH EVER COMES FIRST. (Or 2400 for O-235C and O-235L series in the AA-1x, under certain restrictions.)

Now, how do you feel about that 30 year old engine with "mid-time"? It's already 250% past it's factory recomended TBO! Busting the TBO by a few percent is one thing, by 2-1/2 times is another.

===The Inspection Process===

The inspection should be performed on the plane after the owner and the prospective purchaser have met, flown the plane, and negotiated a price for sale '''in its stated condition'''. The buyer should ask for and the seller should supply a complete list of every known squawk. This along with the Total Time of the airframe, engine and prop, the list of installed equipment and an accounting of the life limited components (spar tubes and wing attach shoulder bolts on AA-5x/AG-5B series, no life limited parts on the AA-1x series) comprise the documentation of the stated condition.

At this point, the price has been agreed to, the buyer wants to purchase the plane, and the seller is willing to sell and warrant the plane to be as represented.

The Pre-Purchase Inspection is now scheduled, with the intent of determining if the plane meets the stated condition by the seller. The purpose is not to pick the airplane to pieces and scare away the buyer or to find thousands of dollars worth of work the seller should pay for, rather it is to establish the true condition of the plane for comparison with the previously prepared squawk list. It's possible (and desireable) to do a PPI on a WRECKED plane. Again, the purpose is to bring to light the true condition of the plane, so that both parties are aware and accept the current condition as the basis for the sale.

It's quite common to surprise the owner with items that are worn, cracked, corroded, etc. And the seller and buyer make adjustments in the price to account for them, or the seller has them repaired to everyone's satisfaction, in order to bring the plane back to the previously stated condition, upon which the sale price was negotiated.

Maintenance: General

2013-08-12T16:55:36Z

Bob Steward: Fixed dead link to FAR 43.13

==Required Information and Documentation==

To do any maintenance, the [http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgFAR.nsf/0/8A94799016ABDEFC852566AB006BC387?OpenDocument FARs require] that you have the manufacturer's current maintenance instructions. These would include the airframe maintenance manual, the illustrated parts catalog, and other service publications such as service bulletins, service letters, etc. However the airframe manufacturer didn't make all the parts that are on the plane. The engine manufacturer has their own set of manuals, as do many accessory manufacturers. Having the manual for the magneto or the brakes and wheels is just as important when working on those accessories as is having the engine or airframe manuals.

That is a lot of manuals to locate, but fortunately, some suppliers are now offering their manuals on CD or even on the Internet. One such forward thinking company is [http://www.parker.com Parker-Hannifin], the makers of Cleveland Wheels and Brakes. They offer manuals in print, on CD, and on the web for their [[Media:AWBPC0001.pdf|Parts Catalog]] (16MB PDF) and their [[Media:AWBCMM0001.pdf|Maintenance Manual]] (16MB PDF). Note that the Cleveland manuals above are as retrieved in October 2009. It would be prudent to check with Cleveland for updates before considering these to be "Current Maintenance Instructions" as called out in FAR 43.13.

Unfortunately, Lycoming only has a small selection of their documents on-line. They can be viewed [http://www.lycoming.com/Lycoming/SUPPORT/TechnicalPublications.aspx here].

==Logbooks and Recording==
The minimum requirements for logging work done on an aircraft or accessory is detailed in [http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgFAR.nsf/0/51C7762D8A02287C86256A65006F7853?OpenDocument FAR 43.9]. A log entry must include a brief description of the work performed, the date the work was completed, the name of the person that performed the work -- if different than the one making the log entry, the name, certificate number and type of the person making the entry and of course the signature, which the FAA says constitutes the approval for return to service.

The description of the work "should be in sufficient detail to permit a person unfamiliar with the work to understand what was done, and the methods and procedures used in doing it". A reference to standard methods, procedures and technical data may be made to keep from making each record too long if extensive work is performed.

The FAA has a detailed Advisory Circular on maintaining records - [http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/cfb1221d9b8038b9862569c40075c77f/$FILE/AC43-9C.pdf AC 43-9C].

Although we all think in terms of those little books that say "Aircraft Log Book" on the cover, the FAA does not actually require that we keep the records of the maintenance in a "log book". They can be a stack of loose sheets in a file folder, or even an electronic record -- like many of the airlines and the military use to track their maintenance. Caution is needed here though, per AC 43-9C, electronics records still have to meet the FAR requirements, including signatures, so a hard copy with a signature still seems to be needed.

With light planes its just easier to use the traditional log book, so that is how most owners of light planes manage their records. For our Grummans, time in service and details of the propeller, engine and airframe all need to be logged, while they could be in one logbook (again, per the AC 43-9C), as a practical matter, it's easier to have three separate log books.

The FAA wants a log book for each "Class 1 Appliance". Class 1 Appliances are those components that have a Type Certificate, such as the Airframe, the Engine, and the Prop(s) or rotor system. In the past it was common to include the prop in the Airframe logs, but more recent thinking in Washington suggests we have a separate prop log. So if someone hasn't already purchased a prop log and begun tracking the prop separately, now would be a good time to obtain one and add it to your maintenance records at the next inspection.

[[Category:Maintenance]]

Maintenance: General

2013-08-12T16:47:41Z

Bob Steward: Fixed dead link to FAR 43.9

==Required Information and Documentation==

To do any maintenance, the [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=687122739e072b94c661c119b25602d0&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.10&idno=14 FARs require] that you have the manufacturer's current maintenance instructions. These would include the airframe maintenance manual, the illustrated parts catalog, and other service publications such as service bulletins, service letters, etc. However the airframe manufacturer didn't make all the parts that are on the plane. The engine manufacturer has their own set of manuals, as do many accessory manufacturers. Having the manual for the magneto or the brakes and wheels is just as important when working on those accessories as is having the engine or airframe manuals.

That is a lot of manuals to locate, but fortunately, some suppliers are now offering their manuals on CD or even on the Internet. One such forward thinking company is [http://www.parker.com Parker-Hannifin], the makers of Cleveland Wheels and Brakes. They offer manuals in print, on CD, and on the web for their [[Media:AWBPC0001.pdf|Parts Catalog]] (16MB PDF) and their [[Media:AWBCMM0001.pdf|Maintenance Manual]] (16MB PDF). Note that the Cleveland manuals above are as retrieved in October 2009. It would be prudent to check with Cleveland for updates before considering these to be "Current Maintenance Instructions" as called out in FAR 43.13.

Unfortunately, Lycoming only has a small selection of their documents on-line. They can be viewed [http://www.lycoming.com/Lycoming/SUPPORT/TechnicalPublications.aspx here].

==Logbooks and Recording==
The minimum requirements for logging work done on an aircraft or accessory is detailed in [http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgFAR.nsf/0/51C7762D8A02287C86256A65006F7853?OpenDocument FAR 43.9]. A log entry must include a brief description of the work performed, the date the work was completed, the name of the person that performed the work -- if different than the one making the log entry, the name, certificate number and type of the person making the entry and of course the signature, which the FAA says constitutes the approval for return to service.

The description of the work "should be in sufficient detail to permit a person unfamiliar with the work to understand what was done, and the methods and procedures used in doing it". A reference to standard methods, procedures and technical data may be made to keep from making each record too long if extensive work is performed.

The FAA has a detailed Advisory Circular on maintaining records - [http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/cfb1221d9b8038b9862569c40075c77f/$FILE/AC43-9C.pdf AC 43-9C].

Although we all think in terms of those little books that say "Aircraft Log Book" on the cover, the FAA does not actually require that we keep the records of the maintenance in a "log book". They can be a stack of loose sheets in a file folder, or even an electronic record -- like many of the airlines and the military use to track their maintenance. Caution is needed here though, per AC 43-9C, electronics records still have to meet the FAR requirements, including signatures, so a hard copy with a signature still seems to be needed.

With light planes its just easier to use the traditional log book, so that is how most owners of light planes manage their records. For our Grummans, time in service and details of the propeller, engine and airframe all need to be logged, while they could be in one logbook (again, per the AC 43-9C), as a practical matter, it's easier to have three separate log books.

The FAA wants a log book for each "Class 1 Appliance". Class 1 Appliances are those components that have a Type Certificate, such as the Airframe, the Engine, and the Prop(s) or rotor system. In the past it was common to include the prop in the Airframe logs, but more recent thinking in Washington suggests we have a separate prop log. So if someone hasn't already purchased a prop log and begun tracking the prop separately, now would be a good time to obtain one and add it to your maintenance records at the next inspection.

[[Category:Maintenance]]

Maintenance: General

2013-08-12T16:44:04Z

Bob Steward: Fixed dead link to Lycoming Service Publications

==Required Information and Documentation==

To do any maintenance, the [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=687122739e072b94c661c119b25602d0&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.10&idno=14 FARs require] that you have the manufacturer's current maintenance instructions. These would include the airframe maintenance manual, the illustrated parts catalog, and other service publications such as service bulletins, service letters, etc. However the airframe manufacturer didn't make all the parts that are on the plane. The engine manufacturer has their own set of manuals, as do many accessory manufacturers. Having the manual for the magneto or the brakes and wheels is just as important when working on those accessories as is having the engine or airframe manuals.

That is a lot of manuals to locate, but fortunately, some suppliers are now offering their manuals on CD or even on the Internet. One such forward thinking company is [http://www.parker.com Parker-Hannifin], the makers of Cleveland Wheels and Brakes. They offer manuals in print, on CD, and on the web for their [[Media:AWBPC0001.pdf|Parts Catalog]] (16MB PDF) and their [[Media:AWBCMM0001.pdf|Maintenance Manual]] (16MB PDF). Note that the Cleveland manuals above are as retrieved in October 2009. It would be prudent to check with Cleveland for updates before considering these to be "Current Maintenance Instructions" as called out in FAR 43.13.

Unfortunately, Lycoming only has a small selection of their documents on-line. They can be viewed [http://www.lycoming.com/Lycoming/SUPPORT/TechnicalPublications.aspx here].

==Logbooks and Recording==
The minimum requirements for logging work done on an aircraft or accessory is detailed in [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=687122739e072b94c661c119b25602d0&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.6&idno=14 FAR 43.9]. A log entry must include a brief description of the work performed, the date the work was completed, the name of the person that performed the work -- if different than the one making the log entry, the name, certificate number and type of the person making the entry and of course the signature, which the FAA says constitutes the approval for return to service.

The description of the work "should be in sufficient detail to permit a person unfamiliar with the work to understand what was done, and the methods and procedures used in doing it". A reference to standard methods, procedures and technical data may be made to keep from making each record too long if extensive work is performed.

The FAA has a detailed Advisory Circular on maintaining records - [http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/cfb1221d9b8038b9862569c40075c77f/$FILE/AC43-9C.pdf AC 43-9C].

Although we all think in terms of those little books that say "Aircraft Log Book" on the cover, the FAA does not actually require that we keep the records of the maintenance in a "log book". They can be a stack of loose sheets in a file folder, or even an electronic record -- like many of the airlines and the military use to track their maintenance. Caution is needed here though, per AC 43-9C, electronics records still have to meet the FAR requirements, including signatures, so a hard copy with a signature still seems to be needed.

With light planes its just easier to use the traditional log book, so that is how most owners of light planes manage their records. For our Grummans, time in service and details of the propeller, engine and airframe all need to be logged, while they could be in one logbook (again, per the AC 43-9C), as a practical matter, it's easier to have three separate log books.

The FAA wants a log book for each "Class 1 Appliance". Class 1 Appliances are those components that have a Type Certificate, such as the Airframe, the Engine, and the Prop(s) or rotor system. In the past it was common to include the prop in the Airframe logs, but more recent thinking in Washington suggests we have a separate prop log. So if someone hasn't already purchased a prop log and begun tracking the prop separately, now would be a good time to obtain one and add it to your maintenance records at the next inspection.

[[Category:Maintenance]]

FunFlyinLocations

2013-07-29T18:18:45Z

Bob Steward: Added KJKA, Gulf Shores AL

'''What is your favorite Fly-in location? Here are some of ours:'''

'''ALABAMA'''
:[http://www.airnav.com/airport/KEKY EKY] Bessemer, AL '''The Hangar''', a new on-field restaurant. [[user:Bob_Steward|Bob Steward]] says: "I've been to this Sports bar with aviation theme, good $100 burger, etc." Region 4 had a fly-in Saturday Feb 21 @ lunch. 9 Aircraft and 18 attendees, reviews were very positive, with requests to meet there again.

:[http://www.airnav.com/airport/KJKA JKA] Gulf Shores, AL Jack Edwards Airport is just off the Gulf Coast, and convenient to many "Beach" activities and lots of choices for food. Jimmy Buffet's sister has a restaurant '''Lulu's at Homeport''' just up the road, as well as every kind of fresh-caught seafood, available from roadside stands to white tablecloth establishments. And don't forget those white sand beaches that AL and FL panhandle coasts are known for...

'''ARKANSAS'''

:[http://www.airnav.com/airport/KMEZ MEZ] Mena, AR Aircraft paint and engine shops -- of interest if you are thinking paint/engine/upholstery. [[User:scoffey|Stephen Coffey]] Be advised, after a long flight, there isn't a beer for MILES. And the Sun Country Inn is much newer/nicer than the other options if you get the "privilege" of getting socked in for 3 days like I did. [[user:Bob_Steward|Bob Steward]] says: "I can second the recommendation for Sun Country Inn. I've stayed there and at 2 other local motels while working at the Mena Airport on various Grummans. Lime Tree has a nice restaurant (Sun Country has no food), but the building is older and the rooms less nice than Sun Country. I ate breakfast at Lime Tree multiple times."

'''FLORIDA'''

:[http://www.airnav.com/airport/55J 55J] Fernandina Beach / Amelia Island. [[User:scoffey|Stephen Coffey]] The Ritz there occasionally does last minute specials at a good price. The airport is a 5 minute cab ride to the hotel. Downtown is kinda quaint and cool. Quick and easy SE get away.

'''GEORGIA'''

:[http://www.airnav.com/airport/KFFC FFC] Falcon Field Peachtree City, GA '''Aircraft Spruce East''', '''Dixie Wing of Confederate Air Force Restoration Center'''

:[http://www.airnav.com/airport/KLZU LZU] Gwinnett County Lawrenceville, GA '''EAA 690 Pancake Breakfast''' 1st Saturday every month. Program follows @ 10:30

:[http://www.airnav.com/airport/KPDK PDK] Dekalb-Peachtree in North Atlanta, GA '''Downwind Restaurant''' (on the second story of the Administration Building next to Epps Air Service). Has balcony/deck for outdoor dining when Wx is good.

:[http://www.airnav.com/airport/KRYY RYY] Cobb County Airport-Mc Collum Field '''Elevation Chophouse''' [[User:scoffey|Stephen Coffey]] "Higher end food, but pretty good. Nice HUGE glass wall facing the runway."

'''KENTUCKY'''

:[http://www.airnav.com/airport/KOWB OWB] Owensboro, KY '''Moonlight BBQ''' (not on field, only a short drive), '''Bill and Carol Scott's Precision Engine''' shop. [[user:Bob_Steward|Bob Steward]] says: "I visit Moonlight BBQ everytime I stop by Precision Engine to see Bill and Carol."

'''NEW JERSEY'''
:[http://www.airnav.com/airport/12N 12N] Aeroflex, NJ '''Kittatiny State Park''' Nice biking and hiking trails start at the airport, Boating - lake 100 yards from the runway. Bring your own inflatable boat or bicycles.

'''PENNSYLVANIA'''
:[http://www.airnav.com/airport/LNS LNS] Lancaster, PA '''Fiorentinos''' Good Italian restaurant located in the terminal building. There is also a small pilot shop located in the FBO. The FBO will send a van for you, or you can walk (~10 minutes).

General

2013-07-26T17:19:39Z

Bob Steward: Added explanation of why calendar years don't match the year model of production

The U.S. Centennial of Flight Commission produced an extensive [http://www.centennialofflight.gov/essay/Aerospace/Grumman-II/Aero39.htm history of Grumman, Post World War II to 1994].

{| class="wikitable"
|+Serial Numbers of Grumman Aircraft
!Model
!First
!Last
!Years
|-
|[[AA1]]||AA1-001||AA1-0459||1968-1971
|-
|[[AA1A]]||AA1A-0001||AA1A-0470||1970-1972
|-
|[[AA1B]]||AA1B-0001||AA1B-0591||1973-1976
|-
|[[AA1C]]||AA1C-0001||AA1C-0211||1977-1978
|-
|[[AA5]]||AA5-0001||AA5-0834||1972-1975
|-
|[[AA5A]]||AA5A-0001||AA5A-0900||1976-1979
|-
|[[AA5B]]||AA5B-0001||AA5B-1323||1974-1979
|-
|[[GA7]]||GA7-0001||GA7-0115||1978-1979
|-
|[[AG5B]]||AG5B-99998||AG5B-10176||1989-1993
|-
|[[AG5B]]||AG5B-10201||AG5B-10252||2002-2006
|}

The model year dates are similar to automobile year models, in that new year production began in the fall of the previous year (September), so there are some that were registered by the FAA during the Fall of the year before the manufacturer's model year, and may show on FAA records to be the earlier calendar year, rather than the model year the manufacturer claims. This becomes less and less important as the planes age, but can be confusing when someone offers a "1975 Cheetah" for sale, when Grumman says that 1976 was the first model year for the Cheetah.

The serial number database above was taken from the manufacturing records, and should be helpful in overcoming disputes about "what year IS it?", when comparing planes.

Wheels

2013-01-15T22:29:47Z

Bob Steward: Updated broken Cleveland link to Wheel and Brake Parts Catalog

== Introduction ==

The Cleveland wheels and brakes on the Grummans are divided into 2 groups with 2 different part numbers.

The early planes from 69-74 have the brake caliper with the smaller piston (30-55B) and a 40-86A Main wheel.

The later planes from 75 on have the brake caliper with the larger piston (30-56B) and a 40-88C Main wheel.

All the single engine Grummans use the part number nose wheel (40-77A).

A common problem on the 30+ year old wheels is CORROSION. The 70's production planes came with wheels that were painted silver on the outside, and had no paint or corrosion protection on the inside. Its not uncommon to take a wheel apart and find that under the excess grease slung into the inside is corrosion so severe as to render the part unusable.

Perhaps like THIS:

[[Image:Wheelcor.jpg|thumb|300px|This wheel is unserviceable and had to be replaced at a cost of several hundred dollars]]

This happens from a lack of proper maintenance in 2 ways.

# Too much grease is left on the wheel bearings when they are installed, and the excess is extruded into the hollow center of the wheel.
# The wrong grease is used and the components of the grease, that cause the lubricant to gel, absorb moisture and when held against the bare metal inner surface of the wheel, cause corrosion to rapidly occur.

As a preventative measure, the wheels should be visually inspected at each annual for condition of the wheel and its data plate, the condition and proper torque of the hardware, and by looking through the axle hole with the bearing removed, the condition of the inside of the wheel. A strong light and some rags to wipe away any grease in the "corners" of the cast stiffeners will help identify areas of concern.

== Wheel Bearings, Dust Seals, and Proper Installation ==

[[User:GregAmy|Greg Amy]] writes:

There are two different sizes of washers on the main wheels of all the single engine Grummans. The two larger ones (153-0400) are used on the inside bearing, while a single smaller one (153-0300) is used on the outer. I had paid close attention to how it was all installed, and it just didn't look right. Even after reading the Cleveland parts book I was still confused. After talking it over with [http://www.bondline.org/index.php/User:Bob_Steward Bob Steward] I got it worked out.

[[Image:DSCN4153.JPG|thumb|300 px|A photo of a wheel to better describe the location, inside the outer wheel half.]]

I've had an ongoing discussion with my IA on some apparently-increasing damage on my wheels. There's a small lip on the inside of the outer wheel half, just above where the outer bearing race is; it's on this lip that the "C"-shaped felt seal retainer rides. Over the last couple of annuals we have been finding on my Tiger that this lip has been wearing significantly. Upon inspecting the order of installation of the parts it appeared that the outer washer/dust seal was wearing on that area. We inspected the washer and could not see how this wear could be avoided.

[[Image:DSCN4154.JPG|thumb|300px|The affected area, about halfway down to the bearing race, below where the retaining ring seats. Notice the "cut ridge" where the too-large washer "threaded" itself into the magnesium. It's possible that this wheel can be reused, as the C-channel seal retainer should seat properly.]]

This year I decided to get to the bottom of this. Per the [http://www.parker.com/literature/Aircraft%20Wheel%20&%20Brake%20Division/AWB%20Static%20Files%20for%20Literature/AWBPC0001.pdf Cleveland parts book], there are two different sizes of washers; each wheel gets two of the larger ones on the inner side, and one smaller washer per wheel, which goes on the outside.

[[Image:Washers.jpg]]

Apparently, however, these washers have been installed incorrectly on my Tiger. Some time back someone had installed one of the larger washers on the outside bearing and we've been dutifully putting them back in that order since (hey it's how they came out!) Unfortunately, this causes two problems: first, the large washer, when placed on the outside, causes the OD of it to ride on the lip in the mag wheel where the seal should ride. Since the washer does not turn this causes significant wear on that lip, and thus the damage to the wheels. Second, using the smaller washer on the inside causes it to get pinched between the axle shaft and the inner bearing; I found wear evidence on the axle shaft on that radius where the bearing is supposed to seat, plus wear marks on the washer itself. Finally, using the larger washer (with a larger ID) on the outside bearing causes the wheel nut to not get a full contact when tightened, and the ID of then is slightly bent (and the bearing is not adequately tightened because of the drag on the washer-to-wheel contact). The larger washers are also further damaged by being "cupped" due to getting forced down to the bearing by the nut. It's really a screwed-up situation all around.

[[Image:DSCN4157.JPG|thumb|300px|Another view of the ridge cut by the too-large washer.]]

[[Image:DSCN4159.JPG|thumb|300px|Here's a situation where the top of the ridge was simply worn down to even with the top of the inner bearing race. In this case the C-channel seal retainer will sit too far in. This wheel half will probably need to be replaced.]]

I've used the current shop as long as I've owned my airplane (1995), and they assure me they pay close attention to the order of removal and installation, but they never questioned if it was correct; thus it appears that this situation has been this way since before I owned it.

I also suggest this is a common problem: [http://www.fletchair.com Fletchair] sent to me two good used wheels and all four outer wheel halves show evidence of the same problem.

The risk of this being installed incorrectly is not particularly dire; in addition to ruining perfectly good parts, the worst that that could happen is damaged bearings and/or a slightly loose wheel nut if the washer(s) were to frag themselves. It's probably not a safety-of-flight issue (a safety-of-taxiing issue?) but I believe it's something that needs to be brought to the attention of all folks working on these airplanes; most of the techs I talked to about it have indicated they were not even aware there were different size washers on these Cleveland brakes! Hey, if you don't pay attention and just pick up a washer at random from the pile, you've got roughly a 1/3 chance of getting the first one wrong, then a 50/50 chance of getting the second one wrong if you get the first one right! Those are not particularly good odds, which explains why there's probably a lot of incorrect airplanes out there.

So remember: the two larger washers go on the inside and the smaller one goes out. I'd be '''very''' interested to hear if others find theirs to be incorrect.

User:Bob Steward

2013-01-15T22:28:50Z

Bob Steward: Updated length of time I've owned Grummans

[[Image:Grumman.jpg]]

I found Grumman Street in the Summer of '05 on a visit to San Francisco to see Mark and Kelly Matthews get married, and to spend some time with SFO local Grumman owners [http://www.bondline.org/index.php/User:WikiSysop Steve Williams], Joe Campbell and Wim Kimmerer. For those wanting to visit Grumman Street themselves, [http://maps.google.com/maps?f=q&hl=en&q=Grumman+St.+Oakland+CA&ll=37.740161,-122.218276&spn=0.004327,0.011415 Google Maps] has the details.

Bob Steward is a Grumman owner for over 27 years (Jan 86), a private pilot with Seaplane and Glider ratings, an aircraft mechanic with an Inspection Authorization, [http://archive.aya.org/star/search/?q=Bob+Steward&n=50 a frequent contributor to the AYA Star] and an active [http://www.eaa.org EAA member] with several [http://home.mindspring.com/~n76lima/n624bd/ homebuilt projects].

Brake Master and Slave Cylinders

2013-01-15T22:23:15Z

Bob Steward: Replacaed broken Wicks AC links to o-ring part numbers with new SkyGeek links.

__TOC__

== Introduction ==

Properly maintaining the brake system on Grumman American aircraft is extremely important because the brakes are the only way to steer the plane on the ground at low speeds where the rudder is ineffective.

The hydraulic brakes use a [http://www.aircraftspruce.com/catalog/lgpages/aeroshell_bflu.php Mil Spec fluid MIL-H-5606G], commonly referred to as "5606". This is a red petroleum-based fluid, as opposed to the Glycol based automotive fluids, and the system is not compatible with any other fluid.

If hydraulic fluid leaks have been found at the brake caliper on either main wheel, the likely causes are worn o-ring, pitted wheel cylinder or cracked wheel cylinder casting at the inlet or bleeder fitting.

The [http://www.parker.com/literature/Aircraft%20Wheel%20&%20Brake%20Division/AWB%20Static%20Files%20for%20Literature/AWBTSG0001-7.pdf Cleveland Wheel and Brake Maintenance Manual] is available on-line. The [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=794f31fd6027b03033374ec96690b9fe&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.10&idno=14 FARs require] the use of the manufacturer's current maintenance instructions, and the Grumman maintenance manual gives very little detail about the wheel and brake system.

== The Wheel Slave Cylinder ==

'''Mechanical Difficulty:''' [[Image:Wrench2.jpg]]

To remove the caliper the 1/4" bolts that hold the outer brake pad retaining plate in place must be removed. The inlet line should then be removed by untorquing the [http://www.aircraftspruce.com/catalog/hapages/an818.php AN 818-4D] line nut. The line nut should require no more than 1/8 turn with a wrench before being free enough to spin off with your fingers. If the threads require a wrench to loosen them further, careful inspection of the line nut and inlet fitting threads is in order.

As soon as the line nut is loosened, 5606 fluid will begin leaking out. A small catch pan is a good idea to prevent a spill and an unsafe condition with a slippery floor. A well prepared mechanic will have an [http://www.purechoicemotorsports.com/index.cfm/page/ptype=product/product_id=68/category_id=87/home_id=-1/mode=prod/prd68.htm AN 806-4D] plug ready to seal the line and prevent losing all the fluid in that side of the brake system!

With the brake line removed the caliper can be pulled inboard and removed from the mounting bracket. Exploded views of the caliper can be found in the [http://www.parker.com/literature/Aircraft%20Wheel%20&%20Brake%20Division/AWB%20Static%20Files%20for%20Literature/AWBPC0001.pdf Cleveland Wheel and Brake Parts Catalog] for easy reference to part numbers and assembly details.

With the caliper off the mounting bracket, slide the inner brake pad and backing plate off the mounting pins and remove the piston. A common method is to wrap the caliper assembly in a rag and apply air pressure to the inlet fitting to drive the piston out of the bore. There is a small amount of fluid that remains in the caliper and eye protection is suggested to prevent a chemical irritation should the remaining fluid spray in the direction of your face.

After the piston is removed, a thorough cleaning of the caliper housing and piston is next. A solvent rinse (mineral spirits or an automotive style "brake cleaner") to degrease, followed by soap and water with a mild abrasive like Scotch-Brite to remove stubborn dirt and oxidation, completed by a fresh water rinse and air drying should be sufficient to allow a good inspection.

Evidence of pitting in the caliper bore is quite common on older components, especially those that have been operated in a corrosive environment. If the pitting is very light, and only at the outer edges of the bore, it may not cause a leak under normal circumstances. The o-ring that seals the piston to the caliper bore is set back from the edge of the piston, so the actual seal takes place deeper in the bore. However as the brake pads and the rotor wear, the piston can move further out and reach a point where the o-ring may leak.

The minimum thickness of the rotor and the minimum thickness of the brake pads are designed such that the piston will not travel too far out of the bore when the minimum thicknesses are reached, and the o-ring will still seal if the bore is in good shape. Allowing the brakes to deteriorate past the point of the recommended minimum thickness can cause the piston to move far enough that the o-ring pops out of the caliper bore, and all brake effectiveness is lost without warning.

After cleaning and inspecting the caliper and piston, I suggest an acid etch and alodine, just like the pre-treatment of structural aluminum in preparation for painting. A coat of zinc chromate or an epoxy primer on the external surfaces, followed by a color coat to protect against future corrosion would be a good idea. The caliper has a data plate on it that identifies the manufacturer (Cleveland), the model and other info like the date of production (month and year) in most cases. If the data plate is missing or unreadable, then the part is technically unairworthy. The good news is, that if you contact Cleveland support at the number in the on line manuals, and you ask '''nicely''' for replacement data plates, they will send them to you AT NO CHARGE. The current production data plates are laser printed on a plastic based label, and just peel off and attach to a clean, smooth surface.

After all the surface prep, primer and paint, the caliper is ready to assemble. Install a new O-ring. Its important to use the correct part number that is made of the right material, and not just some "hardware store" o-ring. The early planes use a 1.5" piston and the later models use a 1.75" piston. The Mil-Spec is an MS28775 in either [http://www.skygeek.com/mil-std-ms28775-222-o-ring.html -222] or [http://www.skygeek.com/mil-std-ms28775-224-o-ring.html -224]. It is important that the o-ring not be twisted in its groove. Lube it and the bore of the caliper with a generous amount of 5606 fluid, and insert the piston with a rotating motion. Once lined up correctly, it will slide into place with a quick motion and be ready to wipe off the excess fluid and install the assembly on the plane.

Refer to the section on [http://www.bondline.org/index.php/%3D%3D_Fixing_soft_brakes_caused_by_fluid_leaks_and_air_in_the_system_%3D%3D bleeding the brakes] for instructions on how to purge the air from the system.

== The Master Cylinders ==

'''Mechanical Difficulty:''' [[Image:wrench3.jpg]]

On most Grummans there are 4 Master Cylinders, a pair for each pilot. They are plumbed such that the pilot's side master cylinder output in hooked to the co-pilot's side master cylinder inlet, and the co-pilot's side master cylinder output is connected to the brake caliper by flex and hard lines.

This means that low fluid in the pilot's side master cylinder can cause a loss of brake effectiveness and a soft pedal, and the co-pilot's side brakes can continue to work.

Removing the brake master cylinders requires disconnecting the flex line from the output, and on the co-pilot's side, also disconnecting the flex line to the input. The master cylinder must be disconnected from its bracket on the floor, and from the brake pedal. The installation hardware can vary from year model to year model, with some having Clevis Pins, some Clevis Bolts, and some AN3 bolts. In all cases the greatest difficulty is in reaching the hardware. The master cylinders are on the firewall side of the rudder pedals, so its awkward to reach the hardware.

Some [http://www.purechoicemotorsports.com/index.cfm/page/ptype=product/product_id=68/category_id=87/home_id=-1/mode=prod/prd68.htm AN806-4D] flare plugs are handy to seal the flex lines as they are disconnected. Unless the fluid has all been drained from the brake system, several ounces of 5606 fluid will leak out when the lines are disconnected.

<TO BE CONTINUED>

Brake Master and Slave Cylinders

2013-01-15T22:18:18Z

Bob Steward: Corrected brake piston size from 2" to 1.75"

__TOC__

== Introduction ==

Properly maintaining the brake system on Grumman American aircraft is extremely important because the brakes are the only way to steer the plane on the ground at low speeds where the rudder is ineffective.

The hydraulic brakes use a [http://www.aircraftspruce.com/catalog/lgpages/aeroshell_bflu.php Mil Spec fluid MIL-H-5606G], commonly referred to as "5606". This is a red petroleum-based fluid, as opposed to the Glycol based automotive fluids, and the system is not compatible with any other fluid.

If hydraulic fluid leaks have been found at the brake caliper on either main wheel, the likely causes are worn o-ring, pitted wheel cylinder or cracked wheel cylinder casting at the inlet or bleeder fitting.

The [http://www.parker.com/literature/Aircraft%20Wheel%20&%20Brake%20Division/AWB%20Static%20Files%20for%20Literature/AWBTSG0001-7.pdf Cleveland Wheel and Brake Maintenance Manual] is available on-line. The [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=794f31fd6027b03033374ec96690b9fe&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.10&idno=14 FARs require] the use of the manufacturer's current maintenance instructions, and the Grumman maintenance manual gives very little detail about the wheel and brake system.

== The Wheel Slave Cylinder ==

'''Mechanical Difficulty:''' [[Image:Wrench2.jpg]]

To remove the caliper the 1/4" bolts that hold the outer brake pad retaining plate in place must be removed. The inlet line should then be removed by untorquing the [http://www.aircraftspruce.com/catalog/hapages/an818.php AN 818-4D] line nut. The line nut should require no more than 1/8 turn with a wrench before being free enough to spin off with your fingers. If the threads require a wrench to loosen them further, careful inspection of the line nut and inlet fitting threads is in order.

As soon as the line nut is loosened, 5606 fluid will begin leaking out. A small catch pan is a good idea to prevent a spill and an unsafe condition with a slippery floor. A well prepared mechanic will have an [http://www.purechoicemotorsports.com/index.cfm/page/ptype=product/product_id=68/category_id=87/home_id=-1/mode=prod/prd68.htm AN 806-4D] plug ready to seal the line and prevent losing all the fluid in that side of the brake system!

With the brake line removed the caliper can be pulled inboard and removed from the mounting bracket. Exploded views of the caliper can be found in the [http://www.parker.com/literature/Aircraft%20Wheel%20&%20Brake%20Division/AWB%20Static%20Files%20for%20Literature/AWBPC0001.pdf Cleveland Wheel and Brake Parts Catalog] for easy reference to part numbers and assembly details.

With the caliper off the mounting bracket, slide the inner brake pad and backing plate off the mounting pins and remove the piston. A common method is to wrap the caliper assembly in a rag and apply air pressure to the inlet fitting to drive the piston out of the bore. There is a small amount of fluid that remains in the caliper and eye protection is suggested to prevent a chemical irritation should the remaining fluid spray in the direction of your face.

After the piston is removed, a thorough cleaning of the caliper housing and piston is next. A solvent rinse (mineral spirits or an automotive style "brake cleaner") to degrease, followed by soap and water with a mild abrasive like Scotch-Brite to remove stubborn dirt and oxidation, completed by a fresh water rinse and air drying should be sufficient to allow a good inspection.

Evidence of pitting in the caliper bore is quite common on older components, especially those that have been operated in a corrosive environment. If the pitting is very light, and only at the outer edges of the bore, it may not cause a leak under normal circumstances. The o-ring that seals the piston to the caliper bore is set back from the edge of the piston, so the actual seal takes place deeper in the bore. However as the brake pads and the rotor wear, the piston can move further out and reach a point where the o-ring may leak.

The minimum thickness of the rotor and the minimum thickness of the brake pads are designed such that the piston will not travel too far out of the bore when the minimum thicknesses are reached, and the o-ring will still seal if the bore is in good shape. Allowing the brakes to deteriorate past the point of the recommended minimum thickness can cause the piston to move far enough that the o-ring pops out of the caliper bore, and all brake effectiveness is lost without warning.

After cleaning and inspecting the caliper and piston, I suggest an acid etch and alodine, just like the pre-treatment of structural aluminum in preparation for painting. A coat of zinc chromate or an epoxy primer on the external surfaces, followed by a color coat to protect against future corrosion would be a good idea. The caliper has a data plate on it that identifies the manufacturer (Cleveland), the model and other info like the date of production (month and year) in most cases. If the data plate is missing or unreadable, then the part is technically unairworthy. The good news is, that if you contact Cleveland support at the number in the on line manuals, and you ask '''nicely''' for replacement data plates, they will send them to you AT NO CHARGE. The current production data plates are laser printed on a plastic based label, and just peel off and attach to a clean, smooth surface.

After all the surface prep, primer and paint, the caliper is ready to assemble. Install a new O-ring. Its important to use the correct part number that is made of the right material, and not just some "hardware store" o-ring. The early planes use a 1.5" piston and the later models use a 1.75" piston. The Mil-Spec is an MS28775 in either [http://www.wicksaircraft.com/catalog/product_detail.php/pid=6320~subid=1689/index.html?PHPSESSID=544f063ebd63b7bfa3ced8221afb67b4 -222] or [http://www.wicksaircraft.com/catalog/product_detail.php/pid=6321~subid=1689/index.html -224]. It is important that the o-ring not be twisted in its groove. Lube it and the bore of the caliper with a generous amount of 5606 fluid, and insert the piston with a rotating motion. Once lined up correctly, it will slide into place with a quick motion and be ready to wipe off the excess fluid and install the assembly on the plane.

Refer to the section on [http://www.bondline.org/index.php/%3D%3D_Fixing_soft_brakes_caused_by_fluid_leaks_and_air_in_the_system_%3D%3D bleeding the brakes] for instructions on how to purge the air from the system.

== The Master Cylinders ==

'''Mechanical Difficulty:''' [[Image:wrench3.jpg]]

On most Grummans there are 4 Master Cylinders, a pair for each pilot. They are plumbed such that the pilot's side master cylinder output in hooked to the co-pilot's side master cylinder inlet, and the co-pilot's side master cylinder output is connected to the brake caliper by flex and hard lines.

This means that low fluid in the pilot's side master cylinder can cause a loss of brake effectiveness and a soft pedal, and the co-pilot's side brakes can continue to work.

Removing the brake master cylinders requires disconnecting the flex line from the output, and on the co-pilot's side, also disconnecting the flex line to the input. The master cylinder must be disconnected from its bracket on the floor, and from the brake pedal. The installation hardware can vary from year model to year model, with some having Clevis Pins, some Clevis Bolts, and some AN3 bolts. In all cases the greatest difficulty is in reaching the hardware. The master cylinders are on the firewall side of the rudder pedals, so its awkward to reach the hardware.

Some [http://www.purechoicemotorsports.com/index.cfm/page/ptype=product/product_id=68/category_id=87/home_id=-1/mode=prod/prd68.htm AN806-4D] flare plugs are handy to seal the flex lines as they are disconnected. Unless the fluid has all been drained from the brake system, several ounces of 5606 fluid will leak out when the lines are disconnected.

<TO BE CONTINUED>

AA5A

2013-01-14T17:33:12Z

Bob Steward: created Serial Number Splits at year models. Previously all started with "0001"

The AA5A was manufactured from 1976 to 1977 by Grumman American, and 1978 to 1979 by Gulfstream Aerospace. There were 900 AA5As produced, 640 by Grumman American and 260 by Gulfstream Aerospace. It was marketed as the Cheetah.

{| class="wikitable"
|+AA5A Serial Numbers
!Year
!First
!Last
|-
|1976||AA5A-0001||AA5A-0282
|-
|1977||AA5A-0283||AA5A-0522
|-
|1978||AA5A-0523||AA5A-0670
|-
|1979||AA5A-0671||AA5A-0900
|}

{| class="wikitable"
|+Bondline Contributors Who Own or Fly AA5As
!Name
!Year
!SN
!N Number
!Handle
|-
|[[user:ddking|Dennis King]]||1976||AA5A-0018||N9652U||none
|-
|[[user:John_Garman|John Garman]]||1976||AA5A-0095||N9595U||none
|-
|[[user:jbowman90|Jason Bowman]]||1976||AA5A-0149||[[user:jbowman90|N9749U]]||none
|-
|[[user:mboyd|Mike Boyd]]||1976||AA5A-0211||N9811U||none
|-
|[[user:ddking|Dennis King]]||1977||AA5A-0321||[[user:ddking|N9921U]]||none
|-
|[[user:Roger_Rucker|Roger Rucker]]||1978||AA5A-0557||[[user:Roger_Rucker|N26390]]||none
|-
|[[user:Hortonjf|John Horton]]||1978||AA5A-0612||N26465||none
|-
|[[user:Mike_Bowman|Mike Bowman]]||1979||AA5A-0884||N3772C||none
|-
|}

[[Category:Cheetah Topics]]

Disassembly

2012-11-26T01:34:38Z

Bob Steward: Added detailed instructions for removing HS and/or Elevators

A request on the GG for information on how to remove your plane from a non-airport landing site by disassembling it enough to fit it on a trailer or flat bed wrecker lead to this article and the check lists below.

[[Image:2-place_no_wings.jpg]][[Image:4placewingsremoved.jpg]]

== Removing the wings (4 place) ==

# Buy a bunch of Zip-Locks bags and a Sharpie to keep track of all your hardware as you remove it.
# Remove the wing tips.
# If you're going to be transporting the wings flat, remove the pitot tube and tie-down rings.
# Remove the aileron to control horn bolt at the center of the fuselage under the back seat (two separate through-bolts on the 4-place).
# Remove the bolts on the outer aileron bearing bracket and aft spar. Hold up the outer aileron to keep it from falling.
# Slide aileron assembly with counterweight and bearing bracket out. May have to rotate it slowly to break the friction on the inner control horn; go slowly.
# Lower flaps to access to the nut on the flap drive arm; remove nut and washer. Alternate method: leave arm attached and move flaps up and down as need to get access to the bolts in the following step. Your goal is to get access to the flap drive clamp bolts, an aluminum block that fits around the large torque tube, in the outboard corners of the "hell hole" under the back seat.
# Back off (''do not remove'') the two "set" bolts on each flap drive torque tube clamp and loosen the pinch bolt at the inboard end of the tube. '''The 2 bolts that pin the clamp to the torque tube need only be backed out 3-4 turns, and will sometimes take the threads out with them if backed completely out.''' As per the above instruction, you may need to move the flaps up and down a couple times to get access to all the bolts. Be patient.
# Pull the torque tube out of the clamp block and first (inner) bearing bracket on the wing.
# Remove outer flap/inner aileron bearing bracket (can be a pain to get to the bolt heads. Again, ''be patient'').
# Slide flap out, some care is needed to break loose the RTV at the inboard end. Repeat flap removal on the opposite side.
# Remove sump covers from under wing root.
# Disconnect pitot line on left wing sump area. The (probably clear) plastic hose that couples the two 1/4" aluminum tubes is probably hard, so just cut the plastic line and replace with a new part (it's cheap) later.
# Disconnect the electrical (pitot, strobes, nav lights, stall warning switch, etc.) in the sump area, both sides. If any wires do not have a connector in that area (for example, if someone added strobes), cuss at your A&P and snip the wire cleanly; you'll add a connector upon re-assembly. If more than one wire needs to be cut, cuss out your A&P some more and clearly mark each wire (colored tape, label maker, etc) so you'll know which is which on re-assembly.
# Drain the fuel from wing root sumps by removing the drain valve and using a large diameter funnel. 8-10" is about as small as you can use and not lose fuel on the ground due to any breeze and to the run-off from the edges of the sump, since the threaded boss is flush with the surface. '''Alternate de-fueling option:''' buy one of those simple "shaker siphons" (example:http://www.boatshowproducts.com/super-siphon-hose) and use that to siphon out the vast majority of the fuel prior to pulling the sump drain. Makes for a lot less mess.
# Do we need to state the obvious about '''using extreme care when de-fueling'''? The stuff is flammable, you know...
# Before you proceed further, here's a '''general AN-type fittings note!'''. You '''must not''' allow the bulkhead (or any) fitting in the wing (or lines) to rotate while you loosen the line nuts, so have the appropriate size wrench handy and HOLD that bulkhead nut against the rib and turn only the line nut. '''Do not''' rely on using leverage on lines or fittings to loosen these AN nuts, '''always''' use backup wrenches. These lines and fittings are not cheap!
# Loosen the fuel lines AT THE SUMP and remove the small vent line (some vent lines have a rubber connection between the wing and the sump line, some have a hard aluminum line with a flare at both ends).
# '''26-gallon "long range" tanks''': there are two round access covers just fore and aft of the sump cover area that give you access to the areas where these fuel lines go ('''not''' the ones outboard of the wing root seal; remove these two covers each side. Once removed you'll see two AN fuel line elbows, one each fore and aft, both sides; remove these elbows and the hard lines that go from these elbows to the fuel sump.
# '''19 gallon tanks''': DO NOT take the 19 gallon tank inspection panel screws out! The first bay on the standard tanks is WET! You will access these fittings as you are removing the wings; see notes below.
# Remove the wing panel to center spar bolts (2 each wing, exactly on the fore and aft centerline of the spar). Judicious use of 3/8-drive socket extensions and swivels may be required; six-point sockets are strongly recommended.
# Position one person at the inboard leading edge, one at the inboard trailing edge and one at the wing tip. The person at the wing tip will lift UP slightly to unbind the wing from the weight pulling down on the socket joint of the wing spar to center section. The two inboard people CAREFULLY rock the wing up and down 1/4"-1/2" at a time - not too much, just a little! - while the person at the tip pulls OUT.
# '''19 gallon tanks''': You will need to move the wing out from the wing root '''only''' an inch or so, to allow access to the AN fuel line fittings at the inboard rib on the 19-gallon tanks. Once it's out an inch remove this line.
# '''26-gallon "long range" tanks''': as long as you removed the fuel lines and elbows as described above, you can remove the wing without removing this lines that go to the tanks. However, take care not ensure you do not damage these extending lines as you are removing the wing, they are coming out of a small hole and can get caught.
# '''All airplanes''': remember you've got wires and hoses that may extend into the wing through holes in the wing root. Do not rotate the wing so much as to damage these.
# With fuel lines loose from wing, rock it as before, nose up and down while pulling outboard. The socket joint is just over 1 foot long, so go slow when you get beyond 8-10" away from the wing root. Pull wing panel off and set on a padded surface.
# Grab your favorite beverage and marvel at what you just accomplished. Then get back to work and get that airplane back in the sky!

There are some differences in removing the 2 place wings. Mostly because of the differences in the fuel system.

Placeholder here to convince some Grumman guru to write up instructions on how to remove the horizontal stabilizers (which you need to do if you're transporting the airplane on public roads on a trailer.)

[[Image:4placetrailer.jpg]]

== Removing the Horizontal Stabilizer and Elevators ==

There are 2 methods, both explained below. Remove the entire assembly with elevators installed, or remove elevators individually, then the Stabilizer by itself. Much of it is in common, differences will be noted, removal of the entire assembly is explained first.

# Remove tailcone plastic under rudder (8 sheet metal screws plus the position light wiring which unplugs at aft bulkhead)
# Remove forward facing HS "fillets" at inboard ends of HS and fuselage sides. (4 screws, one upper and one lower each side, slide forward off clips)
# Remove 8 AN4 (7/16" head) bolts on HS forward attachment (4 each side), exposed when fillets were removed.
# Remove ELT covers on both sides
# Remove cotter pins and clevis bolts from elevator control cables.
# Remove 2 clamp bolts (AN4 - 7/16" heads) on elevator control horns and collect spacers that held the control horns apart.
# Remove cotter pin, nut and bolt at the control horn pivot
# Remove the 2 AN3 (3/16" head) bolts that clamp the trim drive to the jackscrew (under the HS and Elevators, that threaded thingy that comes out of the aft bulkhead). Secure dangling arms so they don't get fouled by other work, and DO NOT disturb the relationship of the threaded trim drive to the barrel nut and trim arms that are now loose. This is a RIGGING component, and quite easy to screw up, if you don't secure it now, so that it can't move.

== For removal of elevators separately skip down to that section now ==

# Remove the control horn to elevator torque tube bolts (Close tolerance AN174 bolts -- 7/16" heads), and carefully wiggle the control horns outboard ~1/4" on each side.
# Using an extension (preferably 1/4" drive), back the upper and lower elevator stop bolts out of the aft bulkhead. They have Jam nuts on them to prevent rotation, which may require untorquing first, but usually the bolts can be unscrewed with the jam nuts left alone. For ease of re-assembly, disturb the jam nuts a little as possible and mark the bolts as "upper" and "lower", so that they can be spun back in to almost exact location, as these set the up and down limits of the elevators and are important rigging components.

Skip down to Removing HS if you are leaving the elevators installed.

== Removing the Elevators separately ==
Having accomplished the steps above, begin here:
# Remove safety wire and bolts that hold the trim "yoke" to the 2 elevators.
# Remove the cotter pins, nuts and clevis bolts that attach the yoke to the individual trim arms.
# Remove yoke and wrap safety wire through each hole where it was bolted to the elevators (forward end) to contain the spacer, etc.
# On each elevator locate the 2 outboard bearing supports (lift elevator up and look in the bottom forward edge for "pockets) with a bolt and some safety wire), and remove safety wire, bolts and washers. Note that elevator will FALL when last bolt is removed, so have a helper support the elevator with the trailing edge UP so you can work on the bolts.
# Slide elevator half straight aft, off of the bearing supports. Repeat last 2 steps for other side.
# Using an extension (preferably 1/4" drive), back the upper and lower elevator stop bolts out of the aft bulkhead. They have Jam nuts on them to prevent rotation, which may require untorquing first, but usually the bolts can be unscrewed with the jam nuts left alone. For ease of re-assembly, disturb the jam nuts a little as possible and mark the bolts as "upper" and "lower", so that they can be spun back in to almost exact location, as these set the up and down limits of the elevators and are important rigging components.
== Removing HS ==

# Reaching inside the ELT covers through the larger hole in the ELT "shelf", if ELT is installed under vertical fin, put a 7/16" wrench or, using a long extension and 7/16" socket, locate the 2 nuts that secure the stiffener rod from the aft bulkhead to the HS forward spar carry through, and hold them as the AN4 (7/16" head) bolts on the pilot's side of the elevator center pivot bearing bracket are removed. (This is the "Trick" to getting the HS off, that all novices can't find, and even a few experienced removers have forgotten when in a hurry. <cough>)
# Remove the 4 AN6 (9/16" head) bolts on the aft spar, remembering that as the last one is pulled, the HS and elevators will come free, and this is NOT a one person job. Support the HS/Elevators at both ends while the last bolt is removed, and slide it straight back, avoiding any side to side or tilting, that can bind the HS against the fuselage and scratch the paint.
# Set on padded surface. Consider taping elevator tips to HS is you left the elevators installed. This makes it easier to move, store and re-hang HS in the future.

User:Bob Steward

2012-06-15T23:57:11Z

Bob Steward: updated years of Grumman ownership

[[Image:Grumman.jpg]]

I found Grumman Street in the Summer of '05 on a visit to San Francisco to see Mark and Kelly Matthews get married, and to spend some time with SFO local Grumman owners [http://www.bondline.org/index.php/User:WikiSysop Steve Williams], Joe Campbell and Wim Kimmerer. For those wanting to visit Grumman Street themselves, [http://maps.google.com/maps?f=q&hl=en&q=Grumman+St.+Oakland+CA&ll=37.740161,-122.218276&spn=0.004327,0.011415 Google Maps] has the details.

Bob Steward is a Grumman owner for over 26 years (Jan 86), a private pilot with Seaplane and Glider ratings, an aircraft mechanic with an Inspection Authorization, [http://archive.aya.org/star/search/?q=Bob+Steward&n=50 a frequent contributor to the AYA Star] and an active [http://www.eaa.org EAA member] with several [http://home.mindspring.com/~n76lima/n624bd/ homebuilt projects].

AA1B

2012-06-15T23:47:50Z

Bob Steward: Updated AA-1B last serial number with info from Garner Rice.

The AA1B was manufactured from 1973 to 1976 by Grumman American. It was marketed as the Trainer and the TR-2.

{| class="wikitable"
|+AA1B Serial Numbers
!Year
!First
!Last
|-
|1973||AA1B-0001||AA1B-0237
|-
|1974||AA1B-0238||AA1B-0445
|-
|1975||AA1B-0446||AA1B-0550
|-
|1976||AA1B-0551||AA1B-0655
|}

{| class="wikitable"
|+Bondline Contributors Who Own or Fly AA1Bs
!Name
!Year
!SN
!N Number
!Handle
|-
|Your Name||Model Year||Serial Number||Tail Number||Your Plane's Nickname
|-
|Thomas & Christine Micke||1972||AA1B-0011||N6211L||Mighty Mouse [http://www.bondline.org/index.php/User:Tcmicke]
|-
|Steve Roberts||1973||AA1B-0164||N641HY||
|-
|Chris Carlson||1973||AA1B-0179||N9679L||Thumper
|-
|Linn Walters||1973||AA1B-0200||N9900L||
|-
|Atakan Sobay||1974||AA1B-0436||N8986L||
|-
|Roger Roy||1974||AA1B-0460||N9869L||
|-
|Ben Kamen||1974||AA1B-0471||N9871L||[http://www.bondline.org/index.php/User:bkamen N9871L]
|-
|David Steward||1976||AA1B-0568||N160DF||[http://www.bondline.org/index.php/User:Hondahaven Money Pit]
|-
|Deems Herring||1976||AA1B-0591||N1491R||
|-
|}

Installing AuCountry Jaguar Cowl on my AA5-B

2011-06-13T19:10:53Z

Bob Steward: Corrected item #3 reference to 3/32" rivets as " countersunk 3/26"

This page is to document the steps I am taking in the process of installation of Jaguar Cowl.

The cowling is available from AuCountry Aviation - www.aucountry.com. 

==Hardware==

The Cowling comes with the Installation Instructions which have a list of Tools and Harware reqirements, but I still had to spend many hours fuguring out exactly where to buy parts, how many and what exact sizes to order. 

The following web sites helped me to figure it out:

http://bobmay.astronomy.net/misc/drillchart.htm - helpes to figure out the numbered drill bit sizes in relation to fractional rivet sizes. 

http://www.hansonrivet.com/w06.htm - solid rivet installation guide. I haven't worked with solid rivets before. Notice suggested Clinch Allowance at the bottom of the chart. It helps to determine the proper rivet length. 

http://www.afscamloc.net/xua/downloads/4002%20Series.pdf - CamLoc selection and installation instructions. 

Here is my parts list(to complement, not replace the list in the Instructions): 
# Rivets to attach the upper cowl halves to the hinge - cherry-max countersunk head 1/8". 38 rivets - 19 on each side. Install manual asks for CR3212-4-2. According to Aircraft spruce <https://www.aircraftspruce.com/catalog/hapages/cherrymax.php> those have grip range 0.63 to .125. I measured hinge thickness + upper cowl thickness = 0.142". Maybe CR3212-4-3 is better? Ordered CR3212-4-2 anyway. Those require drill #30, Aircraft Spruce part 12-04217 and #30 countersink, Aircraft Spruce part 12-00880. The cage for countersinks is Spruce part 12-00940. 
# Nutplates to hold lower cowling halves together. 9 on the bottom + 3 on top. There are also 2 to hold upper cowling halves to lower cowling. Total 14. Install manual asks for MS21048-L-08. I believe Manual says 'countersunk' by mistake. I found those on www.cessnadirect.com. AircraftSpruce has MS21047L08. Aren't they the same? 
# Solid rivets to attach those nutplates, countersunk 3/32". The lower cowl joggle thickness measures between 0.07 and 0.09", the nutplate thickness is 0.035", so the total grip is between 0.105 and 0.125. The clench allowance for 3/32" is 0.094. So need Aircraft Spruce part AN426AD-3-3.5. Ordered 1/8 lb - a lot of rivets to practice on scrap aluminum. Require drill #40, Aircraft spruce part 12-04214 and #40 countersink part 12-00881. 
# Camloc part according to Install Instructions, except they leave out the Camloc receptacles, Aircraft Spruce part 214-16N. Those receptacles require 1/8" rivets. The receptacle plate depth is 0.091, the lower cowl joggle thickness is between 0.114 and 0.134, the 1/8" rivet clinch allowance is .094, so total rivet length between 0.3 and 0.32. Ordered Aircraft Spruce part AN426AD-4-5. Also need Camloc pliers, Spruce part 12-01475, although I used a cut split washer and Cleco pliers instead. According to installation instructions(link above) you need 12mm drill bit for the gromet and 16mm drill bit for the receptacle. 15/32 is .0037" less than 12 mm and 5/8 is .0049 less than 16mm. I will see if they work. 
# Rivet Squeezer, Aircraft Spruce part 12-01462, and two squeezer dies part 12-01466. 
# Clecos, Spruce part 12-01138. 12 to hold lower cowl halves together, 19 to hold the upper cowl halves to the hinge and 10 to hold the upper halves to lower cowl - 31 all together. Cleco pliers, Spruce part 12-10105. 
# Engine hoist, if you will need to adjust the engine alignment. I borrowed one. Torque wrench to torque the engine mounts to 40 ft-lb. I got one on Amazon: http://www.amazon.com/gp/product/B0028081GK (Gorilla Automotive TW605 Torque Wrench)
# Lever to remove the nose strut unless you are prepared to cut off the nose strut fairing boot. I borrowed one and later made my own because the borrowed one was too loose. See instructions here: http://www.bondline.org/wiki/Nose_Strut . Zinc chromate primer - to put the strut back. I orderd one from Fletchair and got a zinc phosphate primer instead. Hope it works the same way.
# Two 1 inch bolts with the same thread as propeller bolts - to hold the spinner backplate in place while fitting the cowl. From local hardware store.
# to be continued. 

==Pre-installation Engine Alignment==

I have just installed a Ly-Con overhauled engine with the new Lord engine mounts with one spacer on each mount. Before installing the Jaguar cowl I am checking the fit against the original cowl. The old bottom Lord mounts were leaking and the spinner was sagging agains the nose bowl. Now the spinner is hanging a little high and a little to the right - see pictures. 

<gallery>
File:Bottom.jpg|Bottm
File:Top.jpg|Top
File:Pilot side.jpg|Pilot side
File:Passenger side.jpg|Passenger side
</gallery>

Not sure how to go about engine alignment I asked for help on Team Grumman. Bob and Gary helped with advice but they didn't quite agree with each other. 
Bob: \"...The method we used before Gary sent out his cowl was to align the spinner with the factory cowling, leaving it perhaps 3/8" high with new mounts, as they sag with age, and in a few months they'd be allowing the spinner to align very closely with the nose bowl. Some argue that the engine will rise up when in flight and pulling against the mount, and it will overcome the sagging in the rubber mounts. This is damned hard to measure in flight. <G> ...\" Full text of Bob's e-mail at the end of the page 
Gary's experience is that engine mounts don't necessarily sag with time and that engine rises agains the cowl in flight. Here is Gary's e-mail: http://forums.matronics.com/viewtopic.php?t=81902 
 

I decided to take a middle road - leave the vertical alignment as is and center the Jaguar cowl vertically with the spinner back plate. 
A few days later I figured I don't need a $200 digital level to check the engine vertical angle. My iPhone has an accelerometer and a quick app search confirmed - there is a digital level app, and it's even free!
http://www.ihandysoft.com/level_free.html 
Here is the result:
<gallery>

File:Engine angle 1.jpg|Calibrating - no plane leveling needed, just press -calibrate-
File:Engine angle 2.jpg|Measuring engine angle
</gallery>
 
So my engine is pointing half a degree up. Should I start worrying? 
 

However I was more concerned with horizontal alignment. As Bob's e-mail at the bottom of this page suggests, there is no direct way to measure the horizontal alignment. The consensus seems to be that the original cowl is the best available reference point. I vaguely remembered that I sometimes I had to hold a little left rudder in cruise, so I added one spacer on the top right mount and one spacer on the bottom right mount. This over-corrected the alignment, but ony a tiny little bit. Maybe I should have used half-thickness spacers, but I don't have any right now. If I will end up holding the right rudder in cruise, I will replace full with half-thickness, but for now I will just align the Jaguar cowl a little tiny bit to the right of the spinner, in case I have to go to half-thickness spacers on the right. 

==First Fitting==
Install instructions don't mention this, but you have to remove the nose strut fairing boot. If you don't want to cut it off, you will have to remove the nose strut. 
Here is the first fitting. The cowl lined up nicely. Only 2 bolt holes are drilled and no trimming yet. The install manual calls for 3/16 drill for screw holes, I am using the 5/32. This gives me a tight fit and a little more room for error. 
To hold the cowling in place I cut a couple of wooden planks to size and jammed them under the bottom corners by the firewall - see pictures. 
In the process of trimming I had to remove and re-install the bottom halves several times. I found it easier to remove the halves clecoed together as one piece instead of removing 12 clecoes every time. I had no exhaust, no nose strut and before removing the cowl I would remove the spinner back plate which was held by two 1 inch bolts from hadware store and would screw one of those bolts back to make sure the flywheel would stay in place.
<gallery>
File:Side View 2.jpg|Side View
File:Top 2.jpg|Top
File:Bottom 2.jpg|Bottom
File:Passenger side 2.jpg|Passenger side
File:Pilot Side 2.jpg|Pilot Side

File:Top Right Corner 2.jpg|Top Right Corner

File:Top Left Corner 2.jpg|Top Left Corner
File:Bottom Right Corner 2.jpg|Bottom Right Corner
File:Bottom Left Corner 2.jpg|Bottom Left Corner
</gallery> 
The last picture - Bottom Left Corner - gave me a little worry at first - the cowl seemed alomst 1/2 inch wider then the fuselage. But this gap dissapeared after I put in the bottom side corner screws.

==Trimming and drilling screw holes==
As I mentioned, I am using the 5/32 drill bit for screw holes - works well for me. 
I ended up enlarging a couple of screw holes for a correct fit, but they are still covered completely by the button head screws so I am not worried. Just in case, I asked Gary for epoxy repair materials and instructions and here is his answer: http://forums.matronics.com/viewtopic.php?t=82085
 Installation instructions recommend using Dremel for trimming so I bought a Dremel. Not needed. I did all trimming with my dry wall sanding block and a pack of 100 dry wall sand paper. Fresh sand paper goes thru the fiberglass like a knife thru butter and you have less chance to screw up and cut too much. 
On the Pilot side I ended up trimming to Gary's trim line but on the Passenger side I hardly had to trim at all.
 
 

====Full Text of Bob's e-mail regarding the engine thrust angle alignment:====
START QUOTE 
\>Please take a look. I wonder if you could please help me regarding the spacers on engine mounts. I just bought a set of new Lord engine mounts. The old bottom ones were leaking and the spinner was sagging about 1/2 inch against the nose bowl rim. Now I have placed 1 spacer on each(as it was before) and torqued it per manual, 40 lb-feet. Before fitting the new cowl I tried the old one to check and found that engine is now hanging a little high against the nose bowl and a little to the right. 

The method we used before Gary sent out his cowl was to align the spinner with the factory cowling, leaving it perhaps 3/8" high with new mounts, as they sag with age, and in a few months they'd be allowing the spinner to align very closely with the nose bowl. Some argue that the engine will rise up when in flight and pulling against the mount, and it will overcome the sagging in the rubber mounts. This is damned hard to measure in flight. <G> Some photographic evidence may be the source of this contention. 

It is required to have 1 full thickness spacer between each lower mount and the engine case. It has to do with clearance of the large mount cups from the engine. This isn't an issue with the Cheetah/Traveler with its smaller cups. Any additional spacers on any of the 4 mount points are optional and "as required" to center the spinner. 

Lord makes, though they are hard to find, 1/2 thickness spacers, which can be used to jack the engine around as needed to center the spinner better than a full thickness one might. I've had them made from AN970-7 washers on occasion when my supply of the Lord half thickness spacers ran out. Any machine shop with a surface grinder can make you some. Etch and prime before installing. 

> My question is - should I try to add spacers to align the spinner to the old cowl before I fit the new cowl, and if you think I should, then why? In other words, why aligning to the old cowl would give me a better thrust angle then relying on the angle provided by the engine mount together with the set of new properly torqued Lord mounts? 

In theory the cowling was built on a jig at the factory and the firewall (Station 50) is the reference for all measurements on the plane, so the jigged cowl mated to the firewall by Grumman would give the proper relationship to the nose bowl opening. 

Gary says his measurements of the engines, when shimmed to align the nose bowl and spinner, are all over the place with respect to the Thrust Angle of the engine (reputed to be 3 degrees down). I've just used the maintenance manual method in the past, and trusted that the factory jigs were accurate. 
If you can determine an accurate reference point (canopy rails are used to level the fuselage fore-aft and laterally), you could begin to measure the actual Thrust Angle of your engine and play with aligning it differently than the Maintenance Manual method suggests. Caution is suggested here, as we are REQUIRED by FAR 43.13 to use the Maintenance Manual methods and tools. If Gary's instructions specifically instruct you to alter the engine Thrust Angle, you can claim that the STC then supercedes the 43.13 requirement. However Gary's anecdotal evidence of differences in various planes, and his discussion on TeamGrumman is not an FAA approved source of data. The factory had good reason to set the engine Thrust Angle down and to the side, and changing it will alter the flying characteristics, possibly in a way that is undesirable, and even unsafe. 

> I guess the left/right angle could be checked by measuring the distance from propeller tips to wings when prop is positioned horizontally. I guess one should try to make sure they are equal. Or not? 

Your assumption that the distance from the prop tips to the wing (tips) should be equal is incorrect. Align per the Maintenance Manual and then take the cowl off and measure back to the firewall from the prop, and you'll see that the engine is TURNED with respect to the firewall. Laying the nose bowl on the ground will quickly show you how offset it is, too. Note that the spinner opening flange is TILTED quite a bit, not only vertically, but to the side as well. 
--Bob Steward 
Birmingham, AL END QUOTE

User:Bob Steward

2011-03-07T19:14:38Z

Bob Steward: Updated number of years of Grumman ownership

[[Image:Grumman.jpg]]

I found Grumman Street in the Summer of '05 on a visit to San Francisco to see Mark and Kelly Matthews get married, and to spend some time with SFO local Grumman owners [http://www.bondline.org/index.php/User:WikiSysop Steve Williams], Joe Campbell and Wim Kimmerer. For those wanting to visit Grumman Street themselves, [http://maps.google.com/maps?f=q&hl=en&q=Grumman+St.+Oakland+CA&ll=37.740161,-122.218276&spn=0.004327,0.011415 Google Maps] has the details.

Bob Steward is a Grumman owner for over 25 years (Jan 86), a private pilot with Seaplane and Glider ratings, an aircraft mechanic with an Inspection Authorization, [http://archive.aya.org/star/search/?q=Bob+Steward&n=50 a frequent contributor to the AYA Star] and an active [http://www.eaa.org EAA member] with several [http://home.mindspring.com/~n76lima/n624bd/ homebuilt projects].

True Confessions

2010-11-24T16:12:18Z

Bob Steward: Rearranged order of the Confessions, so that new ones are added at the TOP of the list.

This page is dedicated to allowing pilots to tell their tale of getting away with something that could have cost them their plane, their license, or their life.

The postings are intended to be informative, and cautionary to others. The submitter may identify themselves, or post anonymously by allowing one of the moderators to place the text on the page, thus preventing others from looking in the "History" of the Wiki to see who made a particular modification.

Please take the stories in the spirit they are offered, that we might all learn from someone's mistake and thus avoid putting ourselves in that position in the future.

At the suggestion of one of the submitters, I've rearranged the Confessions so that the most recent one goes at the top.

----

'''Next True Confession Goes Here'''

----

'''An Elevating Experience'''

After a long weekend, I was returning to my home airport which had a bit of a crosswind. My landing a bit sloppy and I was sure I could do better. So
instead of turning to my tie-down area, and despite being tired, I decided to practice crosswind landings. I taxied back and as I started down the
runway, something very unusual happened.I lifted off way too early. My airspeed was low but I was climbing like an elevator. I pushed the nose
down hard to gain airspeed but continued to climb like crazy. I was sure I set the trim correctly, and verified the indicator was in the takeoff range.
However, a quick check out the window confirmed I just took off with Full Flaps. Once I had enough speed I retracted the flaps and landed fine, and
on the way back to my car I walked the long way around, avoiding the FBO area in case someone noticed.

----

'''Lost in Colorado'''

My private pilot instruction was interrupted by a job transfer from Georgia to Denver Colorado, so I needed more dual instruction to become familiar with a new aircraft and the new terrain. The school plane was an old Warrior that seemed neglected, as most students preferred the newer Cessnas. But I knew I would someday own a Grumman, so I preferred training in planes with the wings mounted correctly, (i.e. low wing).

Having worked my way back up to solo, it was time to do my first solo cross country in the area. This would be my first time venturing away from the Denver area, so I picked an airport just 51 miles away (KLIC). There weren't too many landmarks on my course, but I found a small river and a couple of towers that were in my path. A VOR station was right in the middle so I carefully calculated the TO/FROM vectors. In addition, I dutifully worked the winds, magnetic variations, etc. and set off for my first solo cross country in Colorado.

I was very pleased with by dead reckoning as the VOR indicator was right in the middle. However I failed to spot any of my landmarks. The river, it turned out, was a dry riverbed and the towers were too small to be distinguished from the landscape. Having passed my midway point, I waited for the VOR indicator to flip as I passed the station. It did not change at all! I checked and double checked the frequency but nothing. I had no landmarks, no VOR and my dead reckoning was off. I was lost! How was I going to find this tiny airport now?

Well, I cheated. One week before this flight, I bought a Garmin 296 and stuffed it in my flight bag, just in case. I really did not intend to use it at all, but I sure needed some help. It turned out I wasn't too far off course, but given the lack of landmarks in the area, I probably would have passed right by the destination airport. I later found out that the VOR receiver was inoperable, but the instructor forgot to notify me, and there was no INOP label on the VOR.

After that incident, I decided that I would always know the full condition of the aircraft I was flying, and one way to do that is to own the airplane. So just a few weeks later, I bought my first aircraft, a Grumman of course, with a functional VOR, and my trusty 296 mounted on the yoke.

----

'''Should have gone around, but didn't...'''

My story also concerns go-arounds - the one I should have made and did not. Soloed but not yet licensed, I'd spent the day practicing crosswind landings. Hopped over to a nearby field, hillier and different terrain than my home field. On descent to the runway, it's rough and wild. Too wild for my skill level. Just before touchdown, correcting for left crosswind, I notice the two windsocks, one at each end of the field, pointing in different directions. Right at touchdown, suddenly it's all from the right. My nose swings hard left as the wheels touch and just like that I'm off the runway, into a shallow field of small boulders separating the taxiway from the runway. A few wild bounces later, somehow without dragging a wing or flipping, the plane bounds out of the boulder field onto the taxiway. The only physical damage was one torn wheelpant. What really suffered was my confidence. After waiting for the winds to subside, I somehow took off and got it home, but resolved never to fly again. Thank God for my mature, experienced instructor. He told me some of his own true confessions, and dogged me to get back in the cockpit. I'm licensed now, and deeply grateful for the chance to keep learning. Many successful go arounds later, I have a healthy respect for crosswinds and for the wisdom of going around.

----

'''There is no shame in a go-around!'''

I had just entered the downwind with a bit of extra speed due to merging with a couple of people in the pattern doing touch and go's. On final, I still had
a little more speed than usual, but plenty of runway, so no worries. (Some of you already know what happened next). The mains touched down perfectly, and I
lowered the nose. Then "bounce", I'm in the air again, (rebound from the nose wheel). Oh no, the dreaded porpoise! My first thought was of my instructor
telling me there is no shame in going around. I thought I might have it under control (my bad), but then it bounced again. At this time, the emails I had
read on the Gang kicked in. In particular, I remembered reading one "experienced" contributor's email about putting the throttle to the wall in a
bad situation and how no face lost in a go around, but much face is lost in a botched landing. So I throttled-up and went around. My daughter was my
passenger and she was laughing at the bouncing, "can we do it again". This was much better than me crying over a bent aircraft.

True Confessions

2010-11-24T16:06:31Z

Bob Steward: Added another True Confession

This page is dedicated to allowing pilots to tell their tale of getting away with something that could have cost them their plane, their license, or their life.

The postings are intended to be informative, and cautionary to others. The submitter may identify themselves, or post anonymously by allowing one of the moderators to place the text on the page, thus preventing others from looking in the "History" of the Wiki to see who made a particular modification.

Please take the stories in the spirit they are offered, that we might all learn from someone's mistake and thus avoid putting ourselves in that position in the future.

----

'''There is no shame in a go-around!'''

I had just entered the downwind with a bit of extra speed due to merging with a couple of people in the pattern doing touch and go's. On final, I still had
a little more speed than usual, but plenty of runway, so no worries. (Some of you already know what happened next). The mains touched down perfectly, and I
lowered the nose. Then "bounce", I'm in the air again, (rebound from the nose wheel). Oh no, the dreaded porpoise! My first thought was of my instructor
telling me there is no shame in going around. I thought I might have it under control (my bad), but then it bounced again. At this time, the emails I had
read on the Gang kicked in. In particular, I remembered reading one "experienced" contributor's email about putting the throttle to the wall in a
bad situation and how no face lost in a go around, but much face is lost in a botched landing. So I throttled-up and went around. My daughter was my
passenger and she was laughing at the bouncing, "can we do it again". This was much better than me crying over a bent aircraft.

----
'''Should have gone around, but didn't...'''

My story also concerns go-arounds - the one I should have made and did not. Soloed but not yet licensed, I'd spent the day practicing crosswind landings. Hopped over to a nearby field, hillier and different terrain than my home field. On descent to the runway, it's rough and wild. Too wild for my skill level. Just before touchdown, correcting for left crosswind, I notice the two windsocks, one at each end of the field, pointing in different directions. Right at touchdown, suddenly it's all from the right. My nose swings hard left as the wheels touch and just like that I'm off the runway, into a shallow field of small boulders separating the taxiway from the runway. A few wild bounces later, somehow without dragging a wing or flipping, the plane bounds out of the boulder field onto the taxiway. The only physical damage was one torn wheelpant. What really suffered was my confidence. After waiting for the winds to subside, I somehow took off and got it home, but resolved never to fly again. Thank God for my mature, experienced instructor. He told me some of his own true confessions, and dogged me to get back in the cockpit. I'm licensed now, and deeply grateful for the chance to keep learning. Many successful go arounds later, I have a healthy respect for crosswinds and for the wisdom of going around.

----
'''Lost in Colorado'''

My private pilot instruction was interrupted by a job transfer from Georgia to Denver Colorado, so I needed more dual instruction to become familiar with a new aircraft and the new terrain. The school plane was an old Warrior that seemed neglected, as most students preferred the newer Cessnas. But I knew I would someday own a Grumman, so I preferred training in planes with the wings mounted correctly, (i.e. low wing).

Having worked my way back up to solo, it was time to do my first solo cross country in the area. This would be my first time venturing away from the Denver area, so I picked an airport just 51 miles away (KLIC). There weren't too many landmarks on my course, but I found a small river and a couple of towers that were in my path. A VOR station was right in the middle so I carefully calculated the TO/FROM vectors. In addition, I dutifully worked the winds, magnetic variations, etc. and set off for my first solo cross country in Colorado.

I was very pleased with by dead reckoning as the VOR indicator was right in the middle. However I failed to spot any of my landmarks. The river, it turned out, was a dry riverbed and the towers were too small to be distinguished from the landscape. Having passed my midway point, I waited for the VOR indicator to flip as I passed the station. It did not change at all! I checked and double checked the frequency but nothing. I had no landmarks, no VOR and my dead reckoning was off. I was lost! How was I going to find this tiny airport now?

Well, I cheated. One week before this flight, I bought a Garmin 296 and stuffed it in my flight bag, just in case. I really did not intend to use it at all, but I sure needed some help. It turned out I wasn't too far off course, but given the lack of landmarks in the area, I probably would have passed right by the destination airport. I later found out that the VOR receiver was inoperable, but the instructor forgot to notify me, and there was no INOP label on the VOR.

After that incident, I decided that I would always know the full condition of the aircraft I was flying, and one way to do that is to own the airplane. So just a few weeks later, I bought my first aircraft, a Grumman of course, with a functional VOR, and my trusty 296 mounted on the yoke.

----

'''An Elevating Experience'''

After a long weekend, I was returning to my home airport which had a bit of a crosswind. My landing a bit sloppy and I was sure I could do better. So
instead of turning to my tie-down area, and despite being tired, I decided to practice crosswind landings. I taxied back and as I started down the
runway, something very unusual happened.I lifted off way too early. My airspeed was low but I was climbing like an elevator. I pushed the nose
down hard to gain airspeed but continued to climb like crazy. I was sure I set the trim correctly, and verified the indicator was in the takeoff range.
However, a quick check out the window confirmed I just took off with Full Flaps. Once I had enough speed I retracted the flaps and landed fine, and
on the way back to my car I walked the long way around, avoiding the FBO area in case someone noticed.

----
'''Next True Confession Goes Here'''

True Confessions

2010-11-24T01:48:49Z

Bob Steward: Added another True Confession

This page is dedicated to allowing pilots to tell their tale of getting away with something that could have cost them their plane, their license, or their life.

The postings are intended to be informative, and cautionary to others. The submitter may identify themselves, or post anonymously by allowing one of the moderators to place the text on the page, thus preventing others from looking in the "History" of the Wiki to see who made a particular modification.

Please take the stories in the spirit they are offered, that we might all learn from someone's mistake and thus avoid putting ourselves in that position in the future.

----

'''There is no shame in a go-around!'''

I had just entered the downwind with a bit of extra speed due to merging with a couple of people in the pattern doing touch and go's. On final, I still had
a little more speed than usual, but plenty of runway, so no worries. (Some of you already know what happened next). The mains touched down perfectly, and I
lowered the nose. Then "bounce", I'm in the air again, (rebound from the nose wheel). Oh no, the dreaded porpoise! My first thought was of my instructor
telling me there is no shame in going around. I thought I might have it under control (my bad), but then it bounced again. At this time, the emails I had
read on the Gang kicked in. In particular, I remembered reading one "experienced" contributor's email about putting the throttle to the wall in a
bad situation and how no face lost in a go around, but much face is lost in a botched landing. So I throttled-up and went around. My daughter was my
passenger and she was laughing at the bouncing, "can we do it again". This was much better than me crying over a bent aircraft.

----
'''Should have gone around, but didn't...'''

My story also concerns go-arounds - the one I should have made and did not. Soloed but not yet licensed, I'd spent the day practicing crosswind landings. Hopped over to a nearby field, hillier and different terrain than my home field. On descent to the runway, it's rough and wild. Too wild for my skill level. Just before touchdown, correcting for left crosswind, I notice the two windsocks, one at each end of the field, pointing in different directions. Right at touchdown, suddenly it's all from the right. My nose swings hard left as the wheels touch and just like that I'm off the runway, into a shallow field of small boulders separating the taxiway from the runway. A few wild bounces later, somehow without dragging a wing or flipping, the plane bounds out of the boulder field onto the taxiway. The only physical damage was one torn wheelpant. What really suffered was my confidence. After waiting for the winds to subside, I somehow took off and got it home, but resolved never to fly again. Thank God for my mature, experienced instructor. He told me some of his own true confessions, and dogged me to get back in the cockpit. I'm licensed now, and deeply grateful for the chance to keep learning. Many successful go arounds later, I have a healthy respect for crosswinds and for the wisdom of going around.

----
'''Lost in Colorado'''

My private pilot instruction was interrupted by a job transfer from Georgia to Denver Colorado, so I needed more dual instruction to become familiar with a new aircraft and the new terrain. The school plane was an old Warrior that seemed neglected, as most students preferred the newer Cessnas. But I knew I would someday own a Grumman, so I preferred training in planes with the wings mounted correctly, (i.e. low wing).

Having worked my way back up to solo, it was time to do my first solo cross country in the area. This would be my first time venturing away from the Denver area, so I picked an airport just 51 miles away (KLIC). There weren't too many landmarks on my course, but I found a small river and a couple of towers that were in my path. A VOR station was right in the middle so I carefully calculated the TO/FROM vectors. In addition, I dutifully worked the winds, magnetic variations, etc. and set off for my first solo cross country in Colorado.

I was very pleased with by dead reckoning as the VOR indicator was right in the middle. However I failed to spot any of my landmarks. The river, it turned out, was a dry riverbed and the towers were too small to be distinguished from the landscape. Having passed my midway point, I waited for the VOR indicator to flip as I passed the station. It did not change at all! I checked and double checked the frequency but nothing. I had no landmarks, no VOR and my dead reckoning was off. I was lost! How was I going to find this tiny airport now?

Well, I cheated. One week before this flight, I bought a Garmin 296 and stuffed it in my flight bag, just in case. I really did not intend to use it at all, but I sure needed some help. It turned out I wasn't too far off course, but given the lack of landmarks in the area, I probably would have passed right by the destination airport. I later found out that the VOR receiver was inoperable, but the instructor forgot to notify me, and there was no INOP label on the VOR.

After that incident, I decided that I would always know the full condition of the aircraft I was flying, and one way to do that is to own the airplane. So just a few weeks later, I bought my first aircraft, a Grumman of course, with a functional VOR, and my trusty 296 mounted on the yoke.

----
'''Next True Confession Goes Here'''

True Confessions

2010-11-24T01:10:28Z

Bob Steward: Added another True Confession

Bondline

2010-11-18T16:15:22Z

Bob Steward: Added link to True Confessions under "tips" section.

=Bondline=
__NOTOC__
[[Image:P9130251.JPG|thumb|300 px|Orange Airplane]]

Bondline is a place for [http://en.wikipedia.org/wiki/Grumman Grumman] owners and pilots to share their knowledge.

[http://twitter.com/Bondline Follow Bondline] on [[Image:Twitterlogo.png|63x15px|text-bottom|Twitter]].

== Important Grumman Resources ==

* [http://www.aya.org/ Join AYA, the International Type Club for Grummans ''Now'']!
* Subscribe to the [http://www.ayaforum.org/ AYA Forum].
* Subscribe to the [http://www.grumman.net/ Grumman-Gang] email list. Note that many topics have been covered previously on the Grumman-Gang and can be found in the Grumman-Gang archives, available to subscribers.
* [http://www.fletchair.com FletchAir], the first source for [[FletchAir_Parts|PMA Grumman parts.]]
* [http://p.webring.com/hub?ring=grumman;sid=33;id=33;hub The Grumman Enthusiast's WebRing].

== Technical Information ==

* [[General]]
* [[Maintenance]]
* [[Operations]]
* [[337s]]

== Tips from Bondline Contributors ==

* [[FunFlyinLocations|Fun Fly-In Locations]]
* [[GrummanMechanics|Grumman-Savvy Mechanics]]
* [[True_Confessions|Grumman Owners "True Confessions"]]

True Confessions

2010-11-18T16:12:35Z

Bob Steward: Added "their license" to the opening sentence at the suggestion of John Edwards, because some Confessions might include airspace incursions, etc.

True Confessions

2010-11-17T15:38:24Z

Bob Steward: Added first True Confession and set formatting for future submissions

This page is dedicated to allowing pilots to tell their tale of getting away with something that could have cost them their plane or their life.

The postings are intended to be informative, and cautionary to others. The submitter may identify themselves, or post anonymously by allowing one of the moderators to place the text on the page, thus preventing others from looking in the "History" of the Wiki to see who made a particular modification.

Please take the stories in the spirit they are offered, that we might all learn from someone's mistake and thus avoid putting ourselves in that position in the future.

----

'''There is no shame in a go-around!'''

I had just entered the downwind with a bit of extra speed due to merging with a couple of people in the pattern doing touch and go's. On final, I still had
a little more speed than usual, but plenty of runway, so no worries. (Some of you already know what happened next). The mains touched down perfectly, and I
lowered the nose. Then "bounce", I'm in the air again, (rebound from the nose wheel). Oh no, the dreaded porpoise! My first thought was of my instructor
telling me there is no shame in going around. I thought I might have it under control (my bad), but then it bounced again. At this time, the emails I had
read on the Gang kicked in. In particular, I remembered reading one "experienced" contributor's email about putting the throttle to the wall in a
bad situation and how no face lost in a go around, but much face is lost in a botched landing. So I throttled-up and went around. My daughter was my
passenger and she was laughing at the bouncing, "can we do it again". This was much better than me crying over a bent aircraft.

----

'''Next True Confession Goes Here'''

True Confessions

2010-11-17T15:33:12Z

Bob Steward: Create new

Brake Master and Slave Cylinders

2010-10-23T18:12:04Z

Bob Steward: updated dead link to Cleveland Catalog

__TOC__

== Introduction ==

Properly maintaining the brake system on Grumman American aircraft is extremely important because the brakes are the only way to steer the plane on the ground at low speeds where the rudder is ineffective.

The hydraulic brakes use a [http://www.aircraftspruce.com/catalog/lgpages/aeroshell_bflu.php Mil Spec fluid MIL-H-5606G], commonly referred to as "5606". This is a red petroleum-based fluid, as opposed to the Glycol based automotive fluids, and the system is not compatible with any other fluid.

If hydraulic fluid leaks have been found at the brake caliper on either main wheel, the likely causes are worn o-ring, pitted wheel cylinder or cracked wheel cylinder casting at the inlet or bleeder fitting.

The [http://www.parker.com//literature/Literature%20Files/ag/Aerospace%20Literature/maincov.pdf Cleveland Wheel and Brake Maintenance Manual] is available on-line. The [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=794f31fd6027b03033374ec96690b9fe&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.10&idno=14 FARs require] the use of the manufacturer's current maintenance instructions, and the Grumman maintenance manual gives very little detail about the wheel and brake system.

== The Wheel Slave Cylinder ==

'''Mechanical Difficulty:''' [[Image:Wrench2.jpg]]

To remove the caliper the 1/4" bolts that hold the outer brake pad retaining plate in place must be removed. The inlet line should then be removed by untorquing the [http://www.aircraftspruce.com/catalog/hapages/an818.php AN 818-4D] line nut. The line nut should require no more than 1/8 turn with a wrench before being free enough to spin off with your fingers. If the threads require a wrench to loosen them further, careful inspection of the line nut and inlet fitting threads is in order.

As soon as the line nut is loosened, 5606 fluid will begin leaking out. A small catch pan is a good idea to prevent a spill and an unsafe condition with a slippery floor. A well prepared mechanic will have an [http://www.performanceplumbing.com/AN_Adapters_2.html AN 806-4D] plug ready to seal the line and prevent losing all the fluid in that side of the brake system!

With the brake line removed the caliper can be pulled inboard and removed from the mounting bracket. Exploded views of the caliper can be found in the [http://www.parker.com/literature/Aircraft%20Wheel%20&%20Brake%20Division/AWB%20Static%20Files%20for%20Literature/AWBPC0001.pdf Cleveland Wheel and Brake Parts Catalog] for easy reference to part numbers and assembly details.

With the caliper off the mounting bracket, slide the inner brake pad and backing plate off the mounting pins and remove the piston. A common method is to wrap the caliper assembly in a rag and apply air pressure to the inlet fitting to drive the piston out of the bore. There is a small amount of fluid that remains in the caliper and eye protection is suggested to prevent a chemical irritation should the remaining fluid spray in the direction of your face.

After the piston is removed, a thorough cleaning of the caliper housing and piston is next. A solvent rinse (mineral spirits or an automotive style "brake cleaner") to degrease, followed by soap and water with a mild abrasive like Scotch-Brite to remove stubborn dirt and oxidation, completed by a fresh water rinse and air drying should be sufficient to allow a good inspection.

Evidence of pitting in the caliper bore is quite common on older components, especially those that have been operated in a corrosive environment. If the pitting is very light, and only at the outer edges of the bore, it may not cause a leak under normal circumstances. The o-ring that seals the piston to the caliper bore is set back from the edge of the piston, so the actual seal takes place deeper in the bore. However as the brake pads and the rotor wear, the piston can move further out and reach a point where the o-ring may leak.

The minimum thickness of the rotor and the minimum thickness of the brake pads are designed such that the piston will not travel too far out of the bore when the minimum thicknesses are reached, and the o-ring will still seal if the bore is in good shape. Allowing the brakes to deteriorate past the point of the recommended minimum thickness can cause the piston to move far enough that the o-ring pops out of the caliper bore, and all brake effectiveness is lost without warning.

After cleaning and inspecting the caliper and piston, I suggest an acid etch and alodine, just like the pre-treatment of structural aluminum in preparation for painting. A coat of zinc chromate or an epoxy primer on the external surfaces, followed by a color coat to protect against future corrosion would be a good idea. The caliper has a data plate on it that identifies the manufacturer (Cleveland), the model and other info like the date of production (month and year) in most cases. If the data plate is missing or unreadable, then the part is technically unairworthy. The good news is, that if you contact Cleveland support at the number in the on line manuals, and you ask '''nicely''' for replacement data plates, they will send them to you AT NO CHARGE. The current production data plates are laser printed on a plastic based label, and just peel off and attach to a clean, smooth surface.

After all the surface prep, primer and paint, the caliper is ready to assemble. Install a new O-ring. Its important to use the correct part number that is made of the right material, and not just some "hardware store" o-ring. The early planes use a 1.5" piston and the later models use a 2" piston. The Mil-Spec is an MS28775 in either [http://www.wicksaircraft.com/catalog/product_detail.php/pid=6320~subid=1689/index.html?PHPSESSID=544f063ebd63b7bfa3ced8221afb67b4 -222] or [http://www.wicksaircraft.com/catalog/product_detail.php/pid=6321~subid=1689/index.html -224]. It is important that the o-ring not be twisted in its groove. Lube it and the bore of the caliper with a generous amount of 5606 fluid, and insert the piston with a rotating motion. Once lined up correctly, it will slide into place with a quick motion and be ready to wipe off the excess fluid and install the assembly on the plane.

Refer to the section on [http://www.bondline.org/index.php/%3D%3D_Fixing_soft_brakes_caused_by_fluid_leaks_and_air_in_the_system_%3D%3D bleeding the brakes] for instructions on how to purge the air from the system.

== The Master Cylinders ==

'''Mechanical Difficulty:''' [[Image:wrench3.jpg]]

On most Grummans there are 4 Master Cylinders, a pair for each pilot. They are plumbed such that the pilot's side master cylinder output in hooked to the co-pilot's side master cylinder inlet, and the co-pilot's side master cylinder output is connected to the brake caliper by flex and hard lines.

This means that low fluid in the pilot's side master cylinder can cause a loss of brake effectiveness and a soft pedal, and the co-pilot's side brakes can continue to work.

Removing the brake master cylinders requires disconnecting the flex line from the output, and on the co-pilot's side, also disconnecting the flex line to the input. The master cylinder must be disconnected from its bracket on the floor, and from the brake pedal. The installation hardware can vary from year model to year model, with some having Clevis Pins, some Clevis Bolts, and some AN3 bolts. In all cases the greatest difficulty is in reaching the hardware. The master cylinders are on the firewall side of the rudder pedals, so its awkward to reach the hardware.

Some [http://www.performanceplumbing.com/AN_Adapters_2.html AN806-4D] flare plugs are handy to seal the flex lines as they are disconnected. Unless the fluid has all been drained from the brake system, several ounces of 5606 fluid will leak out when the lines are disconnected.

<TO BE CONTINUED>

Brake Master and Slave Cylinders

2010-10-23T18:10:34Z

Bob Steward: Reverted edits by Bob Steward (Talk) to last revision by Jbowman90

__TOC__

== Introduction ==

Properly maintaining the brake system on Grumman American aircraft is extremely important because the brakes are the only way to steer the plane on the ground at low speeds where the rudder is ineffective.

The hydraulic brakes use a [http://www.aircraftspruce.com/catalog/lgpages/aeroshell_bflu.php Mil Spec fluid MIL-H-5606G], commonly referred to as "5606". This is a red petroleum-based fluid, as opposed to the Glycol based automotive fluids, and the system is not compatible with any other fluid.

If hydraulic fluid leaks have been found at the brake caliper on either main wheel, the likely causes are worn o-ring, pitted wheel cylinder or cracked wheel cylinder casting at the inlet or bleeder fitting.

The [http://www.parker.com//literature/Literature%20Files/ag/Aerospace%20Literature/maincov.pdf Cleveland Wheel and Brake Maintenance Manual] is available on-line. The [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=794f31fd6027b03033374ec96690b9fe&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.10&idno=14 FARs require] the use of the manufacturer's current maintenance instructions, and the Grumman maintenance manual gives very little detail about the wheel and brake system.

== The Wheel Slave Cylinder ==

'''Mechanical Difficulty:''' [[Image:Wrench2.jpg]]

To remove the caliper the 1/4" bolts that hold the outer brake pad retaining plate in place must be removed. The inlet line should then be removed by untorquing the [http://www.aircraftspruce.com/catalog/hapages/an818.php AN 818-4D] line nut. The line nut should require no more than 1/8 turn with a wrench before being free enough to spin off with your fingers. If the threads require a wrench to loosen them further, careful inspection of the line nut and inlet fitting threads is in order.

As soon as the line nut is loosened, 5606 fluid will begin leaking out. A small catch pan is a good idea to prevent a spill and an unsafe condition with a slippery floor. A well prepared mechanic will have an [http://www.performanceplumbing.com/AN_Adapters_2.html AN 806-4D] plug ready to seal the line and prevent losing all the fluid in that side of the brake system!

With the brake line removed the caliper can be pulled inboard and removed from the mounting bracket. Exploded views of the caliper can be found in the [http://www.parker.com/ag/wbd/cleveland/pdf/Wbcov.pdf Cleveland Wheel and Brake Parts Catalog] for easy reference to part numbers and assembly details.

With the caliper off the mounting bracket, slide the inner brake pad and backing plate off the mounting pins and remove the piston. A common method is to wrap the caliper assembly in a rag and apply air pressure to the inlet fitting to drive the piston out of the bore. There is a small amount of fluid that remains in the caliper and eye protection is suggested to prevent a chemical irritation should the remaining fluid spray in the direction of your face.

After the piston is removed, a thorough cleaning of the caliper housing and piston is next. A solvent rinse (mineral spirits or an automotive style "brake cleaner") to degrease, followed by soap and water with a mild abrasive like Scotch-Brite to remove stubborn dirt and oxidation, completed by a fresh water rinse and air drying should be sufficient to allow a good inspection.

Evidence of pitting in the caliper bore is quite common on older components, especially those that have been operated in a corrosive environment. If the pitting is very light, and only at the outer edges of the bore, it may not cause a leak under normal circumstances. The o-ring that seals the piston to the caliper bore is set back from the edge of the piston, so the actual seal takes place deeper in the bore. However as the brake pads and the rotor wear, the piston can move further out and reach a point where the o-ring may leak.

The minimum thickness of the rotor and the minimum thickness of the brake pads are designed such that the piston will not travel too far out of the bore when the minimum thicknesses are reached, and the o-ring will still seal if the bore is in good shape. Allowing the brakes to deteriorate past the point of the recommended minimum thickness can cause the piston to move far enough that the o-ring pops out of the caliper bore, and all brake effectiveness is lost without warning.

After cleaning and inspecting the caliper and piston, I suggest an acid etch and alodine, just like the pre-treatment of structural aluminum in preparation for painting. A coat of zinc chromate or an epoxy primer on the external surfaces, followed by a color coat to protect against future corrosion would be a good idea. The caliper has a data plate on it that identifies the manufacturer (Cleveland), the model and other info like the date of production (month and year) in most cases. If the data plate is missing or unreadable, then the part is technically unairworthy. The good news is, that if you contact Cleveland support at the number in the on line manuals, and you ask '''nicely''' for replacement data plates, they will send them to you AT NO CHARGE. The current production data plates are laser printed on a plastic based label, and just peel off and attach to a clean, smooth surface.

After all the surface prep, primer and paint, the caliper is ready to assemble. Install a new O-ring. Its important to use the correct part number that is made of the right material, and not just some "hardware store" o-ring. The early planes use a 1.5" piston and the later models use a 2" piston. The Mil-Spec is an MS28775 in either [http://www.wicksaircraft.com/catalog/product_detail.php/pid=6320~subid=1689/index.html?PHPSESSID=544f063ebd63b7bfa3ced8221afb67b4 -222] or [http://www.wicksaircraft.com/catalog/product_detail.php/pid=6321~subid=1689/index.html -224]. It is important that the o-ring not be twisted in its groove. Lube it and the bore of the caliper with a generous amount of 5606 fluid, and insert the piston with a rotating motion. Once lined up correctly, it will slide into place with a quick motion and be ready to wipe off the excess fluid and install the assembly on the plane.

Refer to the section on [http://www.bondline.org/index.php/%3D%3D_Fixing_soft_brakes_caused_by_fluid_leaks_and_air_in_the_system_%3D%3D bleeding the brakes] for instructions on how to purge the air from the system.

== The Master Cylinders ==

'''Mechanical Difficulty:''' [[Image:wrench3.jpg]]

On most Grummans there are 4 Master Cylinders, a pair for each pilot. They are plumbed such that the pilot's side master cylinder output in hooked to the co-pilot's side master cylinder inlet, and the co-pilot's side master cylinder output is connected to the brake caliper by flex and hard lines.

This means that low fluid in the pilot's side master cylinder can cause a loss of brake effectiveness and a soft pedal, and the co-pilot's side brakes can continue to work.

Removing the brake master cylinders requires disconnecting the flex line from the output, and on the co-pilot's side, also disconnecting the flex line to the input. The master cylinder must be disconnected from its bracket on the floor, and from the brake pedal. The installation hardware can vary from year model to year model, with some having Clevis Pins, some Clevis Bolts, and some AN3 bolts. In all cases the greatest difficulty is in reaching the hardware. The master cylinders are on the firewall side of the rudder pedals, so its awkward to reach the hardware.

Some [http://www.performanceplumbing.com/AN_Adapters_2.html AN806-4D] flare plugs are handy to seal the flex lines as they are disconnected. Unless the fluid has all been drained from the brake system, several ounces of 5606 fluid will leak out when the lines are disconnected.

<TO BE CONTINUED>

Brake Master and Slave Cylinders

2010-10-23T18:05:05Z

Bob Steward: updated dead link to Cleveland Catalog

__TOC__

== Introduction ==

Properly maintaining the brake system on Grumman American aircraft is extremely important because the brakes are the only way to steer the plane on the ground at low speeds where the rudder is ineffective.

The hydraulic brakes use a [http://www.aircraftspruce.com/catalog/lgpages/aeroshell_bflu.php Mil Spec fluid MIL-H-5606G], commonly referred to as "5606". This is a red petroleum-based fluid, as opposed to the Glycol based automotive fluids, and the system is not compatible with any other fluid.

If hydraulic fluid leaks have been found at the brake caliper on either main wheel, the likely causes are worn o-ring, pitted wheel cylinder or cracked wheel cylinder casting at the inlet or bleeder fitting.

The [http://www.parker.com/literature/Aircraft%20Wheel%20&%20Brake%20Division/AWB%20Static%20Files%20for%20Literature/AWBPC0001.pdf Cleveland Wheel and Brake Maintenance Manual] is available on-line. The [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=e103de20d264f520777ac27466de40b2&rgn=div8&view=text&node=14:1.0.1.3.21.0.363.10&idno=14 FARs require] the use of the manufacturer's current maintenance instructions, and the Grumman maintenance manual gives very little detail about the wheel and brake system.

== The Wheel Slave Cylinder ==

'''Mechanical Difficulty:''' [[Image:Wrench2.jpg]]

To remove the caliper the 1/4" bolts that hold the outer brake pad retaining plate in place must be removed. The inlet line should then be removed by untorquing the [http://www.aircraftspruce.com/catalog/hapages/an818.php AN 818-4D] line nut. The line nut should require no more than 1/8 turn with a wrench before being free enough to spin off with your fingers. If the threads require a wrench to loosen them further, careful inspection of the line nut and inlet fitting threads is in order.

As soon as the line nut is loosened, 5606 fluid will begin leaking out. A small catch pan is a good idea to prevent a spill and an unsafe condition with a slippery floor. A well prepared mechanic will have an [http://www.performanceplumbing.com/AN_Adapters_2.html AN 806-4D] plug ready to seal the line and prevent losing all the fluid in that side of the brake system!

With the brake line removed the caliper can be pulled inboard and removed from the mounting bracket. Exploded views of the caliper can be found in the [http://www.parker.com//literature/Literature%20Files/ag/Aerospace%20Literature/Wbcov.pdf Cleveland Wheel and Brake Parts Catalog] for easy reference to part numbers and assembly details.

With the caliper off the mounting bracket, slide the inner brake pad and backing plate off the mounting pins and remove the piston. A common method is to wrap the caliper assembly in a rag and apply air pressure to the inlet fitting to drive the piston out of the bore. There is a small amount of fluid that remains in the caliper and eye protection is suggested to prevent a chemical irritation should the remaining fluid spray in the direction of your face.

After the piston is removed, a thorough cleaning of the caliper housing and piston is next. A solvent rinse (mineral spirits or an automotive style "brake cleaner") to degrease, followed by soap and water with a mild abrasive like Scotch-Brite to remove stubborn dirt and oxidation, completed by a fresh water rinse and air drying should be sufficient to allow a good inspection.

Evidence of pitting in the caliper bore is quite common on older components, especially those that have been operated in a corrosive environment. If the pitting is very light, and only at the outer edges of the bore, it may not cause a leak under normal circumstances. The o-ring that seals the piston to the caliper bore is set back from the edge of the piston, so the actual seal takes place deeper in the bore. However as the brake pads and the rotor wear, the piston can move further out and reach a point where the o-ring may leak.

The minimum thickness of the rotor and the minimum thickness of the brake pads are designed such that the piston will not travel too far out of the bore when the minimum thicknesses are reached, and the o-ring will still seal if the bore is in good shape. Allowing the brakes to deteriorate past the point of the recommended minimum thickness can cause the piston to move far enough that the o-ring pops out of the caliper bore, and all brake effectiveness is lost without warning.

After cleaning and inspecting the caliper and piston, I suggest an acid etch and alodine, just like the pre-treatment of structural aluminum in preparation for painting. A coat of zinc chromate or an epoxy primer on the external surfaces, followed by a color coat to protect against future corrosion would be a good idea. The caliper has a data plate on it that identifies the manufacturer (Cleveland), the model and other info like the date of production (month and year) in most cases. If the data plate is missing or unreadable, then the part is technically unairworthy. The good news is, that if you contact Cleveland support at the number in the on line manuals, and you ask '''nicely''' for replacement data plates, they will send them to you AT NO CHARGE. The current production data plates are laser printed on a plastic based label, and just peel off and attach to a clean, smooth surface.

After all the surface prep, primer and paint, the caliper is ready to assemble. Install a new O-ring. Its important to use the correct part number that is made of the right material, and not just some "hardware store" o-ring. The early planes use a 1.5" piston and the later models use a 2" piston. The Mil-Spec is an MS28775 in either [http://www.wicksaircraft.com/catalog/product_detail.php/pid=6320~subid=1689/index.html?PHPSESSID=544f063ebd63b7bfa3ced8221afb67b4 -222] or [http://www.wicksaircraft.com/catalog/product_detail.php/pid=6321~subid=1689/index.html -224]. It is important that the o-ring not be twisted in its groove. Lube it and the bore of the caliper with a generous amount of 5606 fluid, and insert the piston with a rotating motion. Once lined up correctly, it will slide into place with a quick motion and be ready to wipe off the excess fluid and install the assembly on the plane.

Refer to the section on [http://www.bondline.org/index.php/%3D%3D_Fixing_soft_brakes_caused_by_fluid_leaks_and_air_in_the_system_%3D%3D bleeding the brakes] for instructions on how to purge the air from the system.

== The Master Cylinders ==

'''Mechanical Difficulty:''' [[Image:wrench3.jpg]]

On most Grummans there are 4 Master Cylinders, a pair for each pilot. They are plumbed such that the pilot's side master cylinder output in hooked to the co-pilot's side master cylinder inlet, and the co-pilot's side master cylinder output is connected to the brake caliper by flex and hard lines.

This means that low fluid in the pilot's side master cylinder can cause a loss of brake effectiveness and a soft pedal, and the co-pilot's side brakes can continue to work.

Removing the brake master cylinders requires disconnecting the flex line from the output, and on the co-pilot's side, also disconnecting the flex line to the input. The master cylinder must be disconnected from its bracket on the floor, and from the brake pedal. The installation hardware can vary from year model to year model, with some having Clevis Pins, some Clevis Bolts, and some AN3 bolts. In all cases the greatest difficulty is in reaching the hardware. The master cylinders are on the firewall side of the rudder pedals, so its awkward to reach the hardware.

Some [http://www.performanceplumbing.com/AN_Adapters_2.html AN806-4D] flare plugs are handy to seal the flex lines as they are disconnected. Unless the fluid has all been drained from the brake system, several ounces of 5606 fluid will leak out when the lines are disconnected.

Once the line(s) and attach hardware are disconnected, the passenger side master cylinders can be removed. The pilot's side, on the early models may also have a mechanical parking brake attached. Some have a ring like a keyring that can be removed from the actuator arm, and some have had safety wire substituted for the link between the chain and the actuator arm. Disconnect the parking brake chains, and remove the pilot's side master cylinders.

The early master cylinders had notches in the rod that engage the parking brake actuator. These notches weaken the rod, and often lead to bends that cause the brake to not actuate fully or possibly to stick. There are no new replacement parts for the Gerdes cylinders, and the answer is to replace them with Cleveland master cylinders, or make replacements as "owner produced parts" as allowed by the FARs. A suggestion for material to use in making a new rod for the master cylinder is a long AN bolt of the correct diameter.

To disassembly the master cylinders, there is a clevis with a jam nut at the top of the rod, and an internal snap-ring that holds the top on the cylinder. It it not always necessary to remove the clevis, and if it is going to be removed, it is important to measure the distance from the clevis to the master cylinder, or to count the turns on the threads as it is being removed, so that it can be assembled to the same length when re-installing.

After the snap-ring is out, the rod may be pulled out, bringing with it the "guts" of the master cylinder.

Be prepared for some fluid to leak, even when the cylinder has been drained. Eye protection is encouraged, as anyone that has gotten a drop of 5606 in their eye will tell you it is a strong irritant.

After the rod and piston assembly are removed from the bore of the cylinder, clean the cylinder housing and bore with a solvent suitable for removing petroleum based residue. Some mineral spirits, "brake clean", etc. works nicely.

With the bore clean, look for vertical scratches or scoring. Such marks can allow the fluid to by-pass the piston and o-rings, causing a loss of brake pressure. The scoring may also damage the o-ring, such that a new o-ring will only temporarily solve the problem, until it too is damaged.

Rigging Checks and adjustments

2010-06-17T13:58:54Z

Bob Steward: Changed protection level for "Rigging Checks and adjustments" ([edit=autoconfirmed] (expires 13:58, 24 June 2010 (UTC)) [move=autoconfirmed] (expires 13:58, 24 June 2010 (UTC)))

== Introduction ==

'''Mechanical Difficulty:''' [[image:wrench.jpg]]

'''This is a job which an owner/pilot can do without any additional supervision or sign off, because you are only CHECKING the control travel, not making adjustments to the primary flight controls.'''

Checking the rigging on a Grumman is a very simple job if you have the factory templates shown in the Maintenance Manual. They are available for rent from [http://www.fletchair.com/catalog/section12.pdf FletchAir] on a weekly basis.

Many rigging checks can be made without the factory templates, with slightly more effort. Each year at the [http://www.aya.org/aya.aspx?pgID=1070 AYA Convention], the rigging templates and the Rigging Check volunteers are available to help owners check for discrepancies in their rigging of their planes.

The goal of rigging checks (and adjustments as needed) is to bring the plane into compliance with its Type Certificate Data Sheet specs, and to improve the handling and performance of the plane. In the hundreds of planes checked at the AYA conventions since 1998-- the first Cody Convention when I spearheaded the effort to start the rigging checks, I have yet to see ONE PLANE that had correct rigging on all surfaces. All that I have personally checked had at least 2 measurements out of spec. Too little or too much control displacement, but always at least 2 out of spec!

Significant performance changes can be obtained by removing the errors and getting the plane correctly rigged. At conventions its been sort of a tradition to help correct the plane that "wins" the worst rigged plane award. There have been elevators without enough UP travel that caused the pilot to always have to land at 90 mph in order to be able to flare, planes with bent outboard aileron bearing brackets that had made it impossible to fly "hands off" since the plane was purchased by its current owner, and an amazing array of other rigging errors that induced all sorts of strange handling characteristics that the owners just put up with. Then there were those rigged so poorly that they had significant performance deficits. Some people have spent many thousands of dollars for "speed mods", and found more performance in FREE rigging adjustments than in all their combined speed mod improvements.

== Rigging Adjustments ==

'''Mechanical Difficulty:''' [[image:wrench2.jpg]]

'''Any adjustments to the flight controls requires appropriate certificates and a log book sign off. You will need an Airframe mechanic to supervise and sign off the following work. '''

After rigging checks determine that there are control travels outside the specified limits, the next step is to attempt to correct the errors. An experienced A&P should be able to use the factory templates, the maintenance manual, and perhaps this page of instructions to correctly rig any Grumman.

=== Elevator and Rudder ===

The adjustments are under the plastic tail cone. They consist of 4 stop bolts with jam nuts on them to prevent unwanted movement of the stops. Loosen the jam nut on the stop in question (7/16" offset box end wrench is the best tool I've found), and then turn the stop bolt IN for more travel and OUT for less. Re-check with template or protractor to confirm the adjustment, and when correct, re-snug the jam nut. Most of the Type Certificate Data Sheet specs give a range of travel that is acceptable. Adjusting to the maximum travel will give the most control authority, and may provide the last bit of control that you need some day.

'''Tip:''' The lower rudder bearing is frequently worn or extruded from cold flow as a result of the constant tension of the rudder cables. To test for this, slowly push the rudder to the stop, such that the control horn JUST touches the stop. Now look closely at the lower bearing and support bracket, and gently push the rudder more firmly against the stop. You will almost certainly see some movement of the rudder torque tube in the bearing. If so, then the rudder will move beyond the initial limits set by the stop as the pivot point moves and changes the geometry of the hinge and stop. A new bearing insert will tighten the clearance up significantly.

=== Elevator Trim ===

The trim tab can not be "adjusted" for total travel, but it can be adjusted to center the travel such that the UP and DN limits are correct. The most common cause of elevator trim miss-rigging is lack of maintenance. The trim wheel in the console between the front seats drives the indicator, and it also drives a pair of bevel gears that convert the motion of the wheel into rotation of the trim drive, a long aluminum tube just above the floor in the tail cone. Failure to clean the old dried grease and grit from the gears, from the bearings that support the trim drive tube, and from the threads and actuator nut in the plastic tail cone can lead to excess torque required to move the trim. This can cause the bevel gears to slip, and cause the trim position indicator to no longer be sync'd with the actual position of the trim. The fix is to clean all the trim drive parts and re-lubricate them, and then set the indicator to match the elevator trim by disengaging the bevel gears and re-meshing them. Its also important to check the backlash in the gears and adjust the depth of their engagement, so that the trim won't easily return to its mis-adjusted state.

=== Flaps ===

The first step is to inspect for the correct AMOUNT of total travel. If the flap motor and drive assembly is moving the flaps too much or too little travel, then its probably a limit switch problem, either adjustment or failure. If the correct amount of travel in total degrees of movement is correct, then the flap drive mechanism can be adjusted via the Heim joints on each side to place the flap in the correct position at the UP stop. The [http://www.aircraftspruce.com/catalog/thumbnails/heim.jpg Heim joints], one pair for each side, are located below and just outboard of the back seat cushion. The seat bottom must be flipped over and the canvas cover removed to be able to see the adjustments. Begin by loosening the jam nut on the threaded area between the joints. Then remove the bolt in the top or bottom Heim joint and allow the joint to disconnect from the flap arms. Rotate the Heim joints relative to one another. Closer together raises the flaps and further apart extends them. Insert the bolt to hold the joint to the flap drive arm and check position of the flap. Repeat until the flap is positioned correctly per the template or protractor. Secure the joint by installing the nut removed earlier and properly snug the jam nut on the threads between the joints. Repeat for the opposite side.

'''Tip''' Many planes have excessive play in the flaps. This seems especially prevalent on the AA-5 series, which have a more complex flap drive and more places to allow wear and increase the play. This would also be a good time to verify that the aileron torque tube is accurately centered within the flap torque tube. This keeps the pins on the special flap drive bolts from possibly wearing a groove in the aileron torque tube.

=== Ailerons ===

Rigging the ailerons are subject to several possible faults. The cables can be incorrectly tensioned, the adjustment of the front cables to the control yoke can be mis-adjusted relative to the aft "turn around" cable that connects the 2 cables from the yokes, the aileron outboard bracket can be bent or damaged, and the outboard aileron bracket can be positioned incorrectly on the aft spar. Any of these can cause large errors in the angular position of the ailerons, and also synchronization problems side to side.

Cable tensioning requires a [http://www.aircraftspruce.com/catalog/topages/cablemeter.php cable tensiometer], which ought to have its calibration checked, if you are unsure of its testing and certification status. The basic operation is to clamp the tensiometer onto the cable in question and read the tension on the scale appropriate for the diameter of the cable. Adjustments are made by removing the safety wire or locking clip that holds the turnbuckle such that it can not let the cables unscrew from its ends. The first thing one needs to know about turnbuckles is that they have RH threads on one end, and LH threads on the other, such that if one holds the cable ends, and rotate the turnbuckle, you will either loosen or tighten the cable tension. It is important that you not turn one cable to change the tension.

The [http://www.aircraftspruce.com/catalog/appages/cliplocking.php safety clips] or the [http://www.aircraftspruce.com/catalog/appages/safetywire.php safety wire] are NOT to be reused, so be sure to have some on hand before you start. Additionally you will need to be familiar with the [[correct way to safety wire a turnbuckle]], you might be surprised at the number of A&Ps that can't do it right without looking at the book. The advantage of the [http://www.wicksaircraft.com/catalog/product_cat.php/subid=3606/index.html MS21256] style safety clips is that they are quick and easy to install correctly. (Note that both the -1 and the longer -2 size clips are needed on Grummans, depending on which cable system is being worked on.} They clips can be installed one-handed in a tight spot where trying to wrap safety wire would be very difficult. I've seen a mix of turnbuckles installed on the fleet. Some have the groove in the threads for the safety clips, and some don't, so safety wire may be the only option in some cases.

== Repairs When Adjustments Won't Correct the Rigging ==

[[Image:Wrench3.jpg]]'''-''' [[Image:Wrench4.jpg]]

Sometimes there is damage to the plane, or in rarer cases, planes that left the factory without the means to achieve the correct control travel. In these cases, more extreme measures are needed. The good news is that the approved data to make these repairs has already been published in most every case.

'''Tip'''

Because these procedures involve work that is very Grumman specific, and in most all cases new holes being drilled, these may be jobs that should involve one of the more experienced Grumman mechanics and some scheduling and travel, rather than giving the local Cessna dealer the job.

=== Drooping Aileron Counterweight ===

Incorrect drilling by the factory, or in the case of a new aileron being installed in the field, incorrect drilling by the installer. Unique to the AA-5x series. Grumman published a factory repair.
You can tell that your plane has this problem if you hold each aileron centered by putting your thumb and finger on the trailing edge of the wing tip and holding the aileron such that it has equal thickness above and below the wing tip, and then reaching under the wing tip to feel if the aileron counterweight is 1/4"-3/8" inside the wing tip. If its flush with the lower surface, then its a little out of position, and if its actually below the lower surface, then its far enough out of position that its affecting the up and down limits of travel, and should be re-drilled per the factory instructions.

=== Aileron throw incorrect ===

See Drooping aileron counterweight as one possible cause. Another is a bent or mis-positioned outboard aileron bearing bracket. The proper repair for a bent aileron outboard bearing bracket is a NEW BRACKET from [http://www.fletchair.com FletchAir]. To determine if the bracket is bent, remove it and check on a flat surface to see if the center line of the bearing hole is the same, no matter which side you view it from. Check the bracket with a square to see that it does not lean to either side. To detect a mis-positioned outboard bearing bracket, measure the centerline of the bearing bracket from both surfaces of the wing (after confirming the bracket is straight, per the above instructions), and if not, examine the aft spar and the mounting holes for evidence that the bracket was drilled off center top to bottom. To repair a mis-positioned outboard bearing bracket, a doubler of at least the thickness of the aft spar is fabricated to fill the space on the front side of the aft spar (note proper radius to match the stamped curve in the rib), and it is double-flush riveted, such that the new holes to be drilled in the aft spar will not interfere with the rivets. The bearing bracket is clamped into place and the new holes are drilled through the spar and the doubler. Slightly longer AN3 bolts will be needed to account for the spar doubler.

=== Split Elevator ===

When each half of the elevator is at a different angle. Check for this by aligning one elevator tip with the horizontal stabilizer, and then measuring the opposite tip to see if its mis-aligned with the stabilizer. Even slight differences in the zero position of the two tips can induce a rolling moment that must be corrected by adjusting the aileron trim tabs. This causes drag from the elevators and from the ailerons, and can add up to several knots of speed lost on the top end. The factory designed repair is the align the tips and ream the bolt hole(s) with a "G" letter reamer and install an NAS 6604 "X" oversize bolt to fill the larger hole. This mates the elevator half to the control horn and can cause fit up issues should the elevator ever need to be replaced. Because the oversize bolt is only ~0.015" oversize, there is only a small amount of adjustment in elevator alignment available. It is suggested that one side be re-drilled, moving the elevator halves as close to aligned as the bolt diameter increase will allow, and then, if needed, the other side be drilled to center it to the first side, thus doubling the total error that can be corrected. After reaming the holes it will be necessary check and adjust the elevator stops for proper travel.

=== Excess Play in Flaps ===

There are a number of causes, all wear related. The difficulty is in locating the real cause.

It can be the bearings on the flap drive tubes, the bracket that holds the flap drive tube on the inside of the honeycomb, the flap motor bracket cracking under the motor where it can not be seen unless the motor is removed, the bearings at the ends of the jack shaft that transfers the movement to the other side, or in the links that connect the jack shaft to the arms on the flap drive tubes. A little play in 3 or 4 locations can be several degrees by the time its all added up at the flap trailing edge. If your flaps have play, its probably a good plan to start on the list above and check/repair each item until you have eliminated the play.

=== Split Flaps ===

Although probably not showing up as a rigging problem right now, ANY history of split flap extension requires careful investigation, because the problem did not "heal" itself, and lies dormant waiting for a bad moment to re-appear. The flaps are driven by an aluminum arm that clamps the flap drive tube and is pinned by a pair of special bolts. The tip of the bolt has the threads removed, such that a round pin is created, and this pin fits into a hole in the flap drive tube. Improper assembly causes the flap drive tube to not be properly aligned when the pinning bolts are tightened, and this causes the bolt to deform the tube rather than to lock it in place. This leaves only the friction of the clamp to hold the flap in alignment, and sets the stage for split flaps. The repair is to remove the flap drive tube and either do some blacksmithing to raise the dimpled metal and restore the holes to flush with the rest of the tube, or to swap sides with the tubes and use the other set of factory drilled holes to install the pinning bolts correctly.

File:2009-26-12.pdf

2010-01-08T19:08:44Z

Bob Steward: Updated AD on ECI cylinders. Expanded serial number range to be tested. 4 Feb 2009 effective date

Updated AD on ECI cylinders. Expanded serial number range to be tested. 4 Feb 2009 effective date

Repair of Debonding

2009-11-18T20:09:22Z

Bob Steward: Changed SK-125 verbiage at the request of Garner Rice. Garner assures Bondline that this document IS in the Public Domain.

Aside from problems with the infamous purple glue, used in late '74 through early '76 models, that resulted in [http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/15ABBB4154F287DA86256A38005E36C8?OpenDocument AD 76-17-03], there can be random debonding on the rest of the fleet. Often this is the result of corrosion.

[[Image:Corrosion_under_bonds.jpg]] [[Image:corrosion2.jpg]]

The staggered holes in the bonded area were drilled to allow the skin and ribs to be clecoed together in the same alignment that they were bonded, before the extent of the corrosion was determined. This created a "matched hole tooling" effect, much like [http://vansaircraft.com/public/kit-std.htm Van's RV series] uses on their airframes to reduce the amount of jigging that must be done to assemble the planes.

The factory provided data to be used in doing repairs of all types of debonding with the publication of Service Kit 125A. The short version is that nearly any debonding can be repaired with this data. That is good news for owners and mechanics as we attempt to preserve the aging fleet and repair various damage that is unrelated to the spontaneous debonding. The factory data doesn't speak to HOW or WHY the debonding occurred, so that means that if we intentionally debond the parts to replace a corroded or dented part, we are still allowed to use the SK-125A methods to install the replacement parts.

SK-125A calls out an "inhibited poly-sulfide sealant", which is the same Mil-Spec as high adhesion fuel tank sealant, and [http://www.pegasusautoracing.com/bigpicture.asp?RecId=3466 NAS1097] reduced head rivets to replace the original factory bond. Cleaning of the surfaces to be re-bonded is also explained, and care must be taken not to introduce contaminants that might initiate future corrosion.

[[Image:Debonded elevator 001 (Small).jpg|200px|thumb|left|Elevator Debonding]]

[[Image:Debonded elevator 3 (Small).jpg|200px|thumb|right]]

==Grumman American Service Kit No. 125A==

Thanks to the support and generosity of FletchAir Parts, and Garner Rice in particular, a copy of SK-125A is available. This data was released by Grumman American before the copyright law changed in 1987, which had required an explicit "©" copyright symbol to denote that there was copyright on a document. The data is hosted here as a service to the community, and is presumed to be in the Public Domain.

[[Media:SK-125A Grumman .pdf|SK125A]].

Bondline:Current events

2009-10-26T16:18:05Z

Bob Steward: Removed out of date fly-in

'''Southern Region Fly-in:'''

'''What:''' [http://www.bondline.org/wiki/Halloween_Flyin_Party Hal Beauchesne's Halloween Happening Fly-In and Costume Party]

'''When:''' Oct. 31, 2009

'''Where:''' [http://www.airnav.com/airport/KEDN Enterprise, AL (KEDN) Enterprise Municipal]

'''Who:''' Hal Beauchesne (Bo-shane) 334-347-7360 (home) 334-301-9641 (cell) <halb@roadrunner.com> for details

'''Four Corners Region Aviation Event:'''

'''What:''' Tucson Treasure Hunt

'''When:''' Nov 7, 2009

'''Where:''' [http://www.airnav.com/airport/KTUS Tucson, AZ (KTUS) Tucson International Airport]

'''Who:''' http://www.ninety-nines.org/events/index.cfm?id=23 for details

'''Southern Region Fly-in:'''

'''What:''' Wings-N- Wheels car show and fly in

'''When:''' Nov. 7, 2009 The event starts around 9am and goes to 3-4pm

'''Where:''' [http://www.airnav.com/airport/KDRI Deridder, LA (KDRI) Beauregard Regional]

'''Who:''' Steve Tyer 214-883-0099 <stevetyer@gmail.com> for details

Maintenance: General

2009-10-15T18:26:12Z

Bob Steward: Added suggestion to check Cleveland for manual updates

==Required Information and Documentation==

To do any maintenance, the [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=687122739e072b94c661c119b25602d0&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.10&idno=14 FARs require] that you have the manufacturer's current maintenance instructions. These would include the airframe maintenance manual, the illustrated parts catalog, and other service publications such as service bulletins, service letters, etc. However the airframe manufacturer didn't make all the parts that are on the plane. The engine manufacturer has their own set of manuals, as do many accessory manufacturers. Having the manual for the magneto or the brakes and wheels is just as important when working on those accessories as is having the engine or airframe manuals.

That is a lot of manuals to locate, but fortunately, some suppliers are now offering their manuals on CD or even on the Internet. One such forward thinking company is [http://www.parker.com Parker-Hannifin], the makers of Cleveland Wheels and Brakes. They offer manuals in print, on CD, and on the web for their [[Media:AWBPC0001.pdf|Parts Catalog]] (16MB PDF) and their [[Media:AWBCMM0001.pdf|Maintenance Manual]] (16MB PDF). Note that the Cleveland manuals above are as retrieved in October 2009. It would be prudent to check with Cleveland for updates before considering these to be "Current Maintenance Instructions" as called out in FAR 43.13.

Unfortunately, Lycoming only has a small selection of their documents on-line. They can be viewed [http://www.lycoming.textron.com/main.jsp?bodyPage=support/publications/maintenance.html here].

==Logbooks and Recording==
The minimum requirements for logging work done on an aircraft or accessory is detailed in [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=687122739e072b94c661c119b25602d0&rgn=div8&view=text&node=14:1.0.1.3.20.0.363.6&idno=14 FAR 43.9]. A log entry must include a brief description of the work performed, the date the work was completed, the name of the person that performed the work -- if different than the one making the log entry, the name, certificate number and type of the person making the entry and of course the signature, which the FAA says constitutes the approval for return to service.

The description of the work "should be in sufficient detail to permit a person unfamiliar with the work to understand what was done, and the methods and procedures used in doing it". A reference to standard methods, procedures and technical data may be made to keep from making each record too long if extensive work is performed.

The FAA has a detailed Advisory Circular on maintaining records - [http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/cfb1221d9b8038b9862569c40075c77f/$FILE/AC43-9C.pdf AC 43-9C].

Although we all think in terms of those little books that say "Aircraft Log Book" on the cover, the FAA does not actually require that we keep the records of the maintenance in a "log book". They can be a stack of loose sheets in a file folder, or even an electronic record -- like many of the airlines and the military use to track their maintenance. Caution is needed here though, per AC 43-9C, electronics records still have to meet the FAR requirements, including signatures, so a hard copy with a signature still seems to be needed.

With light planes its just easier to use the traditional log book, so that is how most owners of light planes manage their records. For our Grummans, time in service and details of the propeller, engine and airframe all need to be logged, while they could be in one logbook (again, per the AC 43-9C), as a practical matter, it's easier to have three separate log books.

The FAA wants a log book for each "Class 1 Appliance". Class 1 Appliances are those components that have a Type Certificate, such as the Airframe, the Engine, and the Prop(s) or rotor system. In the past it was common to include the prop in the Airframe logs, but more recent thinking in Washington suggests we have a separate prop log. So if someone hasn't already purchased a prop log and begun tracking the prop separately, now would be a good time to obtain one and add it to your maintenance records at the next inspection.

File talk:SIL+MS-1.pdf

2009-10-04T06:56:20Z

Bob Steward: Added Mirror comment

This file carries no specific Copyright statement, but is presumably copyrighted. However it has been available as a free download from the Precision Airmotive, for the widest possible distribution. Therefore, like other information from various manufacturers that support the airworthiness of our aircraft, it should be available to all owner/pilots. Bondline makes no claim of ownership, nor is it suggested that the right to make derivative works extends to this file, like most all content on Bondline which is released under the '''Attribution-NonCommercial-ShareAlike 2.5''' license. It is placed here for convenience purposes as a "mirror" of the original Precision Airmotive posting to the internet and it is not owned by Bondline.

File talk:SIL+MS-1.pdf

2009-10-04T06:40:11Z

Bob Steward: Notice that this service instruction letter is not released under Attribution-NonCommercial-ShareAlike 2.5 license

File:SIL+MS-1.pdf

2009-10-04T06:32:40Z

Bob Steward: Precision Airmotive Service Instruction Letter MS-1, lubrication of accelerator pump rods on the HA-6 carburetor.

Precision Airmotive Service Instruction Letter MS-1, lubrication of accelerator pump rods on the HA-6 carburetor.

Bondline:Current events

2009-09-23T13:13:57Z

Bob Steward: Corrected Hal's fly-in from Southeastern Region to Southern Region

'''Four Corners Region Aviation Event:'''

'''What:''' Copperstate Fly-In

'''When:''' Oct. 22-24, 2009

'''Where:''' [http://www.airnav.com/airport/KCGZ Casa Grande, AZ (KCGZ) Casa Grande Municipal]

'''Who:''' http://www.copperstate.org/csj/ for details

'''Southern Region Fly-in:'''

'''What:''' [http://www.bondline.org/wiki/Halloween_Flyin_Party Hal Beauchesne's Halloween Happening Fly-In and Costume Party]

'''When:''' Oct. 31, 2009

'''Where:''' [http://www.airnav.com/airport/KEDN Enterprise, AL (KEDN) Enterprise Municipal]

'''Who:''' Hal Beauchesne (Bo-shane) 334-347-7360 (home) 334-301-9641 (cell) <halb@roadrunner.com> for details

'''Four Corners Region Aviation Event:'''

'''What:''' Tucson Treasure Hunt

'''When:''' Nov 7, 2009

'''Where:''' [http://www.airnav.com/airport/KTUS Tucson, AZ (KTUS) Tucson International Airport]

'''Who:''' http://www.ninety-nines.org/events/index.cfm?id=23 for details

'''Southern Region Fly-in:'''

'''What:''' Wings-N- Wheels car show and fly in

'''When:''' Nov. 7, 2009 The event starts around 9am and goes to 3-4pm

'''Where:''' [http://www.airnav.com/airport/KDRI Deridder, LA (KDRI) Beauregard Regional]

'''Who:''' Steve Tyer 214-883-0099 <stevetyer@gmail.com> for details

Bondline:Current events

2009-09-23T13:12:41Z

Bob Steward: Removed out of date fly-in

'''Four Corners Region Aviation Event:'''

'''What:''' Copperstate Fly-In

'''When:''' Oct. 22-24, 2009

'''Where:''' [http://www.airnav.com/airport/KCGZ Casa Grande, AZ (KCGZ) Casa Grande Municipal]

'''Who:''' http://www.copperstate.org/csj/ for details

'''Southeastern Region Fly-in:'''

'''What:''' [http://www.bondline.org/wiki/Halloween_Flyin_Party Hal Beauchesne's Halloween Happening Fly-In and Costume Party]

'''When:''' Oct. 31, 2009

'''Where:''' [http://www.airnav.com/airport/KEDN Enterprise, AL (KEDN) Enterprise Municipal]

'''Who:''' Hal Beauchesne (Bo-shane) 334-347-7360 (home) 334-301-9641 (cell) <halb@roadrunner.com> for details

'''Four Corners Region Aviation Event:'''

'''What:''' Tucson Treasure Hunt

'''When:''' Nov 7, 2009

'''Where:''' [http://www.airnav.com/airport/KTUS Tucson, AZ (KTUS) Tucson International Airport]

'''Who:''' http://www.ninety-nines.org/events/index.cfm?id=23 for details

'''Southern Region Fly-in:'''

'''What:''' Wings-N- Wheels car show and fly in

'''When:''' Nov. 7, 2009 The event starts around 9am and goes to 3-4pm

'''Where:''' [http://www.airnav.com/airport/KDRI Deridder, LA (KDRI) Beauregard Regional]

'''Who:''' Steve Tyer 214-883-0099 <stevetyer@gmail.com> for details

Engine Baffles

2009-09-21T03:30:45Z

Bob Steward: Added photo and description of pilot side baffle mod for Sky-Tec starter

The engine baffles are critical to proper operation of the engine. They provide the sides for the box that holds the cooling air, and they also direct the air around the cylinder fins to minimize hot spots.

Its very common to see the metal portion of the baffles cracked and fretted from vibration, and to see the rubber seals hardened from heat and age, missing sections and replaced with the wrong types of material. The orange silicone rubber is the most popular replacement material, and its not really suitable for the job.

The rubber baffle seal needs to be thin and flexible, and it should have some fiber reinforcement to prevent tearing. The orange silicone rubber is too thick (1/8"), has no reinforcement, and tears easily.

When installing a lightweight starter such as the Sky-Tec, the front metal baffles on the 75 Traveler and all Cheetahs and Tigers must be trimmed to clear the different contour of the starter motor and solenoid.

Here are some examples of the trimming:

[[Image:Center-trim.jpg]]

[[Image:LH-Skytec.jpg]]

This is a seal I added to decrease the air leakage around the starter.

[[Image:Skytec-seal.jpg]]

This is seal for the pilot's side of the starter, that allows one to clear out the baffle to a larger rectangle, and then rivet on a cover plate that can be trimmed to match the starter contour without multiple removals of the baffling. This is very similar to the design used by later American General and the Tiger LLC plane's baffles. It is also workable to install the add-on plate with sheet metal screws, rather than permanently attach it with rivets.

[[Image:Skytec-seal_pilot-side.jpg]]

[Gil Alexander] The seal is a little harder to form on the outboard side of the starter due to the starter leads. One example of sealing is here. The baffle material is extended as much as possible over the top of the starter to get into the gaps created above the starter.

[[Image:Sky-tec-gaps.jpg]]

Also check all of the baffle attach points. This AA5B broken bracket was hard to see, but was obviously not doing it's job. It is attached to the baffles by the oil cooler and held by the upper left engine mount bolt. A previous repair was less than effective. New brackets are available at Fletchair.

[[Image:Broken-baffle-bracket.JPG]]

==Cheetah Baffles - Part of my Hunt for High Oil Temperatures==
I have a Cheetah that suffered from higher oil temperatures than I'm comfortable with (CHT's look OK) during the warmest summer months. Everything has been done to this engine to make it run warm (High Compression mod, LASAR system) so this is not a big surprise. But hearing that people fly these machines in Arizona in the summer and the fact that I'm a bit of a perfectionist...I wanted to see if there is anything I could do to lower the temps.

In the course of chasing down the issue, (besides checking the oil cooler, vernatherm valve, and other system components) the old and ratty baffle seals were replaced under the supervision of one of the most Grumman knowledgeable shops around. After the seals were replaced, the following summer my temperatures were actually worse than the previous year. And thus began my education in the proper fit of baffle seals...

===Finding Problems===
I started by simply taking a flashlight and looking into the cooling air intakes in the nose bowl. I found several places where the seals did not sit flush against the cowl. In one location the seal bowed enough to create a quarter sized hole. This occurred because in the replacement of the seals, the multiple separate pieces of seal material were replaced with a few single longer strips of seal material that would buckle when pressed against the cowl where they were supposed to seal. Where the seals along the back and sides overlapped, they were attached together in such a way as to pull them away from the cowl. So, I removed these attachments and determined where to cut slits in the seal material so it would sit flush.

I then started looking around the nose bowl seals and found a number of locations where the seal fit was as poor as the seals against the cowl doors. I had to pull the cowl and hold the nose bowl in position as best I could (by holding it relative to the spinner/prop just as it looked when the cowl was attached) and inspect the seal fit. I used a marker to mark the locations where the seal did not fit well and made a number of additional slits in the ribbons of seal material. Often these slits were made where the contours of the cowl or nose bowl change. The seal near the landing light needed to be trimmed to fit the contour of the landing light recess in the nose bowl. There was also a location near the alternator where a longer strip of seal material was needed to close a hole caused by the additional distance between the baffle and the nose bowl in that area.

After 20 or more new slits in the baffle seal material and a new piece near the alternator, I put things back together and used a combination of drop lights and flashlights to check how well the seals were seating. Everything looked good, so I reassembled the cowl, checked the baffles one more time, and waited for the warm summer days to return for the tests.

===Test Flight===
Well, summer returned and I went on a test flight. The temps were lower...but only back to the point they were prior to replacing the seals. So, I continued my search. Off came the cowl and nose bowl and I found the seal around the starter (a location Bob mentioned above) was not that tight in spots and completely missing along the top of the starter (between the starter and the engine case) in what would equate to about a 1" x 3" hole. So, I constructed and installed a seal to close the hole. I also replaced the seal around the pipe that provides air to the muffler shroud as I determined the seal material there was the original and in bad shape. I then put everything back together and and performed a couple test flights. Things were looking better, but when the high temps of July and August hit, the oil temps wee still a bit high.

===Gathering Data===
[[Image:Manometer.JPG|thumb|100px|right|Manometer]]Stumped, I decided to try collecting some figures on the cooling. I constructed a simple water manometer to determine the pressure differential between the high pressure and low pressure side of the baffles. After some searching around the internet, I found that for effective cooling you need a pressure difference of at least 6" of water. We ran the tubing ends of the manometer from the cockpit out the canopy and in thru the oil door with one tube on each side of the baffle in the cowl. In flight we were able to determine that in cruise around 120 mph IAS the pressure difference was right around 6" of water. In a 100 mph IAS climb, the pressure dropped to around 5". So, the numbers indicated that I still had some issues as I was just barely coming into an acceptable cooling pressure range in cruise.

===The latest (and hopefully last) find===
So, my A&P (who had been overseeing my work all along) and I tried to find any other possible problems. After a bunch of snooping around with flashlights and inspection mirrors, my A&P was able to find another hole hiding in the seals. This hole was located just above the airbox and was caused by the fact that the standard width of the seal material sold in rolls is not wide enough to close a gap in that area. So, I obtained a larger piece of seal material (around 4.5" wide, if memory serves), off came the cowl and nose bowl again, and replaced the pieces that were too short.

===Pictures of the Results===
Below are several pictures of my baffle seals after the changes. Most of the slits you see were added as part of my attempts to improve the fit/seal. Sorry, I didn't take any before pictures, maybe I'll remember next time.
[[Image:UpperLeftSeals11u.JPG|thumb|200px|left]]
[[Image:UpperRightSeals11u.JPG|thumb|200px|none]]
[[Image:LowerSeals11u.JPG|thumb|200px|left]]
[[Image:LowerRightSeals11u.JPG|thumb|200px|none]]

===Conclusion (sort of)===
Of course, by the time we found and fixed this last issue, the hot summer temperatures had given way to cooler ones of fall. The oil temperatures have looked good since the last fix, but I guess I won't know for sure if the problem is resolved until summer returns again. I'll probably try the manometer again to see what it says...when my mechanic and I get a chance. I'll keep you posted. In the meantime, I hope this information helps if you have a Cheetah experiencing similar issues.

One last note. I was supplied the silicone type baffle seal material by the shop where the seals were initially replaced. I've found that this material isn't necessarily the best for seals as it is rather thick and does not "set" (retain a curved form) so you have to wrestle with it and be careful of the fit anytime you need to close the cowl or install the nose bowl.

==Cooling Outlet Ducts in Lower Cowl==
[[Image:Tiger-sagging-outlet-duct.jpg|thumb|200px|left]]
After the air has passed over the cylinders, it still needs to leave the cowl area. The pre-78 fibreglas ducts are somewhat heat sensitive, and will deform over time, reducing the area of the air outlet, as seen in this photo from Gil Alexander.

File:Skytec-seal pilot-side.jpg

2009-09-21T03:25:13Z

Bob Steward: A photo of an alteration to the pilot side baffle to install a Sky-Tec LS series starter on a Cheetah or Tiger.

A photo of an alteration to the pilot side baffle to install a Sky-Tec LS series starter on a Cheetah or Tiger.

Bondline:Current events

2009-09-17T12:53:17Z

Bob Steward: Added Hal's Halloween Fly-in

'''Southeastern Region Fly-in:'''

'''What:''' Winder Fly-in @ Spitfire Grill

'''When:''' Sep. 19, 2009

'''Where:''' [http://www.airnav.com/airport/KWDR Winder, GA (KWDR) Northeast Georgia Regional]

'''Who:''' Don Weiman 706-658-0095 <Don@Weiman.US> for details

'''Four Corners Region Aviation Event:'''

'''What:''' Copperstate Fly-In

'''When:''' Oct. 22-24, 2009

'''Where:''' [http://www.airnav.com/airport/KCGZ Casa Grande, AZ (KCGZ) Casa Grande Municipal]

'''Who:''' http://www.copperstate.org/csj/ for details

'''Southeastern Region Fly-in:'''

'''What:''' [http://www.bondline.org/wiki/Halloween_Flyin_Party Hal Beauchesne's Halloween Happening Fly-In and Costume Party]

'''When:''' Oct. 31, 2009

'''Where:''' [http://www.airnav.com/airport/KEDN Enterprise, AL (KEDN) Enterprise Municipal]

'''Who:''' Hal Beauchesne (Bo-shane) 334-347-7360 (home) 334-301-9641 (cell) <halb@roadrunner.com> for details

'''Four Corners Region Aviation Event:'''

'''What:''' Tucson Treasure Hunt

'''When:''' Nov 7, 2009

'''Where:''' [http://www.airnav.com/airport/KTUS Tucson, AZ (KTUS) Tucson International Airport]

'''Who:''' http://www.ninety-nines.org/events/index.cfm?id=23 for details

'''Southern Region Fly-in:'''

'''What:''' Wings-N- Wheels car show and fly in

'''When:''' Nov. 7, 2009 The event starts around 9am and goes to 3-4pm

'''Where:''' [http://www.airnav.com/airport/KDRI Deridder, LA (KDRI) Beauregard Regional]

'''Who:''' Steve Tyer 214-883-0099 <stevetyer@gmail.com> for details

Halloween Flyin Party

2009-09-17T12:44:41Z

Bob Steward: Create Halloween Fly-in page

HAL'S HALLOWEEN HAPPENING!!

Join us for a AYA Fly-in Saturday October 31, 2009 at (EDN) Enterprise, AL.

A BBQ lunch will be served 11:00 am until 12:30 pm, lunch will be provided by Hal Beauchesne for the first 40 people, with door prizes for the fly-in awarded after lunch.

Transportation to and from the Army Aviation Museum, Ft. Rucker for a tour will be provided. We return to the Airport by 4:00 pm with transportation to the Hotel and to a Dinner and Halloween party Saturday night at 6:00 pm at a private residence. Prizes will be awarded for the costume contest. The lunch, dinner and party and transportation are free.

Accommodations: Holiday Inn Express, Enterprise (334-347-2211 ask for AYA Fly-In rate $70.00 per night)

Please RSVP by e-mail or phone.
Point of contact Hal Beauchesne (bo-shane) 334-347-7360 (home) 334-301-9641 (cell)or Vickie Beauchesne 334-348-2660 (work)
Preferred email halb@roadrunner.com

Early arrivals Friday afternoon will be met and provided transportation and invited to join us for dinner.

Hal & Vickie Beauchesne
Tiger N920GT

Bondline:Current events

2009-09-10T01:44:25Z

Bob Steward: Added Casa Grande Municipal

'''Southeastern Region Fly-in:'''

'''What:''' Winder Fly-in @ Spitfire Grill

'''When:''' Sep. 19, 2009

'''Where:''' [http://www.airnav.com/airport/KWDR Winder, GA (KWDR) Northeast Georgia Regional]

'''Who:''' Don Weiman 706-658-0095 <Don@Weiman.US> for details

'''Four Corners Region Aviation Event:'''

'''What:''' Copperstate Fly-In

'''When:''' Oct. 22-24, 2009

'''Where:''' [http://www.airnav.com/airport/KCGZ Casa Grande, AZ (KCGZ) Casa Grande Municipal]

'''Who:''' http://www.copperstate.org/csj/ for details

'''Four Corners Region Aviation Event:'''

'''What:''' Tucson Treasure Hunt

'''When:''' Nov 7, 2009

'''Where:''' [http://www.airnav.com/airport/KTUS Tucson, AZ (KTUS) Tucson International Airport]

'''Who:''' http://www.ninety-nines.org/events/index.cfm?id=23 for details

'''Southern Region Fly-in:'''

'''What:''' Wings-N- Wheels car show and fly in

'''When:''' Nov. 7, 2009 The event starts around 9am and goes to 3-4pm

'''Where:''' [http://www.airnav.com/airport/KDRI Deridder, LA (KDRI) Beauregard Regional]

'''Who:''' Steve Tyer 214-883-0099 <stevetyer@gmail.com> for details

Bondline:Current events

2009-09-09T19:17:48Z

Bob Steward: Updated contact info on Winder Fly-in

'''Southeastern Region Fly-in:'''

'''What:''' Winder Fly-in @ Spitfire Grill

'''When:''' Sep. 19, 2009

'''Where:''' [http://www.airnav.com/airport/KWDR Winder, GA (KWDR) Northeast Georgia Regional]

'''Who:''' Don Weiman 706-658-0095 <Don@Weiman.US> for details

'''Four Corners Region Aviation Event:'''

'''What:''' Copperstate Fly-In

'''When:''' Oct. 22-24, 2009

'''Where:''' [http://www.airnav.com/airport/KCGZ Casa Grande, AZ (KCGZ)]

'''Who:''' http://www.copperstate.org/csj/ for details

'''Four Corners Region Aviation Event:'''

'''What:''' Tucson Treasure Hunt

'''When:''' Nov 7, 2009

'''Where:''' [http://www.airnav.com/airport/KTUS Tucson, AZ (KTUS) Tucson International Airport]

'''Who:''' http://www.ninety-nines.org/events/index.cfm?id=23 for details

'''Southern Region Fly-in:'''

'''What:''' Wings-N- Wheels car show and fly in

'''When:''' Nov. 7, 2009 The event starts around 9am and goes to 3-4pm

'''Where:''' [http://www.airnav.com/airport/KDRI Deridder, LA (KDRI) Beauregard Regional]

'''Who:''' Steve Tyer 214-883-0099 <stevetyer@gmail.com> for details

Bondline:Current events

2009-09-09T13:48:27Z

Bob Steward: Added phone number