Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 496 / 881

CHART 3403. TROUBLESHOOTING (AIRSPEED TUBES AND INDICATOR)
ATTITUDE AND DIRECTION.
MAGNETIC COMPASS.
The magnetic compass is a self-contained instrument. This instrument has an individual light which is
connected to the instrument lighting circuit. The compass correction card is located in the card holder mounted on
the instrument. The compass should be swung whenever instruments or radios are changed and at least once a
year.
ADJUSTMENT OF COMPASS.
Before attempting to compensate compass, every effort should be made to place the aircraft in simulated flight
conditions; check to see that the doors are closed, flaps in retracted position, engines running, throttles set at
cruise position and aircraft in level flight attitude. Aircraft master switch, alternators, radios (except for
combustion heater) should be on. All other cockpit controlled electrical switches should be in the off position.
1. Set adjustment screws of compensator on zero. Zero position of adjusting screws is when the dot of the
screw is lined up with the dot of the frame.
2. Head aircraft on a magnetic North heading. Adjust N-S adjustment screw until compass reads exactly North.
3. Head aircraft on a magnetic East heading and do the same as Step 2, adjusting E-W adjusting screw.
4. Head aircraft on magnetic South heading and note resulting South error. Adjust N-S adjusting screw until
one-half of this error has been compensated. No compensation adjustment shall be made with the
combustion heater operating.
5. Head aircraft on magnetic West and do same as Step 4, adjusting E-W adjustment screw.
6. Head aircraft in successive magnetic 30 degree headings and record compass readings on appropriate
deviation card. Deviations must not 10° on any heading. An additional deviation card will have to
be made out for the combustion heater. This second deviation card shall be accomplished under the above
conditions, except the combustion heater shall be operating.
Trouble Cause Remedy
Airspeed changes as aircraft Water in static line. Remove lines from static
is banked. instruments and blow out
lines from cockpit to pitot-
static head.
— Note —
When any connections in the static system are opened for check, system must be
rechecked per Part FAR 23.1325.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
3 4 - 2 1 - 0 1
Page 34-06
Revised: May 15, 1989
2I24
PIPER AIRCRAFT