(PaulaJay1) wrote in
:

Flew to dinner today with an outside temp of 10F. Auto pilot worked
OK on the trip out (plane came out of a 45F hanger). Parked for
dinner for about 2 hours. The autopilot didn't work on the way back.
You could feel the clutch take hold but no corrective action to follow
the bug. Simple roll control didn't respond either. Well, about 20
minutes into the flight home, it started to work. OK all the way
home.

I have to disagree with Jay. If the roll control wouldn't do anything,
then it's not the DG or AI. It's either in the autopilot "computer"
(the part in the panel) or the motor (okay, a cable problem is possible,
but unlikely).

The clutch isn't much, a simple solenoid connected through the autopilot
left hand switch. Take every resistor and transistor and capacitor out
of the circuit the clutch would still work. But beyond that, lots of
thing could stop the "computer" from working. Just kill the reference
oscillator would do it. [Okay, if the excitation coil in BOTH the DG
and AI went out (or only one, if their is a NAV Coupler in between),
then that could do it.]

I'm guessing a cold solder joint or a capacitor gone temp. sensitive.

Next time you are playing around in those types of temperatures, take
the computer inside with you (it comes out fairly easily). See if the
failure repeats.

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James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
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