Navaid Devices AP-1, Руководство пользователя

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(3) The autopilot works well in Wing Leveler mode, but not in Track mode. Why?
The error signal developed as a result of the airplane being a little off course is quite
subtle compared to the relatively large signal caused by a banking airplane. Sometimes
the autopilot works in WING LEVELER even though there may be problems significant
enough to keep it from doing a proper job in TRACK mode.
There are a number of different ailments that can cause the above symptom. The
following is suggested as a systematic way of trouble-shooting:
A) Verify that you really have a problem.
Sometimes first time users think that the airplane is not tracking when everything is
working normally. Do not give up if the airplane does not immediately hold track.
Read the flight test procedure again, paying particular attention to that portion
dealing with trimming the autopilot. If the trim is not set properly, the aircraft will
not track properly.
Even though you are quite careful, sometimes a trim error large enough to affect
tracking exits at the time the autopilot is switched into TRACK MODE. Make sure
you followed the correct trim procedure, then let the airplane drifts out as much as 5
miles. If the airplane turns to run a course parallel to that called for by the GPS or
LORAN, or flies a different radial toward the VOR, just adjust the trim knob. Trim
toward the needle deflection.
B) Verify that a tracking signal is present at the input to the AP-1.
The receiver could be broken, or the signal wiring could be faulty (open, shorted to
ground, or reversed).
If you can switch to another receiver, try that. Chances are that two receivers are not
both broken at the same time.
If you are trying to track a GPS, a quick check is to switch to the VOR and roll the
OBS back and forth. If the wings follow the CDI needle, you have a signal and
should be able to track the VOR. If your wings roll against the needle, your signal
wires to the VOR (but not necessarily the GPS) are reversed.
If you use just one receiver, put a voltmeter across the tracking signal leads at the
AP-1 connector. You should be able to measure 150 millivolts (0.15 volts) between
the two wires (the voltage from either wire to ground is irrelevant) when the CDI
shows 5 dots deviation. The polarity of this voltage should reverse if the direction of
deviation is reversed.