Instrumentation

DRAFT NEW PAGE - Gil Alexander NEEDS A&P SIGN-OFF - and 337 filed for STC. Installation of Mitchell Instrument STC gauge package.

Items needed but not supplied...

1. #8 ring terminals with 1/4 inch hole (instructions say to just use existing wiring, but my plane - 77 Tiger - used 3/16 terminals on the power wiring to the old ammeter)

2. New hoses to senders - I used new AN-4 firesleeved hoses - 10.5 inches for fuel pressure and 18 inches for oil pressure - but 16 inch would probably be better - see later pics.

3. Clamps to mount the senders, 5/8 for the engine mount side and 1 9/16 for the senders. Instructions call for all clamps to be cushioned MS21919, however the oil pressure sender does not have a ground connection, and cushioned clamps do a good job of electrical isolation. Since my supply house did not have 1 9/19 plain clamps, I found that a 1 7/16 cushioned clamp with the rubber removed worked well. The AN3 bolt that is used to connect the small and large clamps can be used for a ground point.

3. Usual assortment of #20 aircraft wire and good quality ring terminals and splices.

4. You need to connect 3 or 4 wires into a single wire in four places, I found that soldering and a good quality heat shrink worked well. Check with your A&P on this and do what he/she prefers.

5. AN929-4D caps (2)- to seal off the old fittings that penetrated the firewall.

6. AN910-4D couplings (2) and AN816-4D (2) pipe thread to flare fitting to connect the sensors to the hoses.

Wiring the gauges

The guages need quite a bit of work wiring before any installation. Since each guage is a separate module, all of the common wiring (power, grounds, lighting) need to be connected together. This is how I did it....