Quarter Windows

Replacing Quarter Windows

Maintenance Difficulty:

The quarter windows are very similar on the AA-1x and the AA-5x series. The AA-1x windows and the AA-5 windows before the '74 model year (those without a baggage door) are cut from flat acrylic sheet. AA-5 and AA-5x from '74 year model through the current production AG-5B Tigers have windows that have been heat formed to a compound curve.

To replace the quarter windows, remove the interior trim surrounding the window. There are a series of very small sheet metal screws (#4) that hold the plastic trim on. There are a few more screws at the forward edge of the turtle deck that clamp the forward edge of the plastic trim, these must be removed, too.

With the plastic trim off, now would be a good time to inspect it for cracks and chips, and perhaps repair it using the methods in the maintenance manual. More info on interior plastic repairs is available on Bondline.

Under the plastic trim are several small formed aluminum brackets that clamp the window in place. Remove the screws that hold the clamps in place and pop them loose from the plexiglass with a putty knife if needed. Sometimes the sealant that the window is bedded in can cause the clamp strips to adhere.

Remove the window. Probably some prying with a thin bladed putty knife will be needed to free it from the fuselage. After the window is out remove all traces of the sealant putty on the fuselage window frame. This will likely be quite hard from age, and require some careful work to break it free. Some will come off in strips or chunks and other sections will have to be scraped off. Use care not to score the aluminum structure and sand the inside lip smooth after all putty is removed. A coat of a quality brand of rattle can red oxide primer will restore the look and some of the corrosion protection of the OEM primer used on the planes from mid 76 on.

While the primer is drying sand the edge of the new window completely smooth with no lower than 400 grit sand paper. The goal is to remove the tool marks on the edge to leave a stress free surface. Plexiglass expands and contracts much more than aluminum when subjected to "normal" temperatures on the ramp and in flight. This continual changing in size causes any discontinuity in the edge to become a stress concentration, and leads to small cracks and crazing in the corners, long before the window should need to be replaced. Examine the old windows on most light planes and you'll see those cracks forming in the corners.

Once the edge of the window has an even "fogged" look to it with no scratches or tool marks left, clean away all the sanding dust (a vacuum is helpful) and avoid any rubbing motion that will scratch the window with the dust and abrasive particles. Apply the self-adhesive felt or the foam tape to the edge. A 1" wide piece applied exactly on the center of the edge will fold over about 7/16" on both sides and can be rubbed to a smooth wrinkle free surface. Place the window up into the frame by inserting the TOP edge in first and then lifting the bottom edge up and sliding it into position. The window must bend to match the curve of the fuselage. The AA-1x and early AA-5 windows will tend to spring back flat and be harder to position than the later AA-5x windows that were formed to a curvature. They will require some bending to install, also, but will not tend to spring back flat because they are already close to the correct contour.