Piper Cherokee Six Service Manual page 513

PIPER CHEROKEE SIX SERVICE MANUAL
9-38. MAGNETIC COMPASS.
9-39. GENERAL. 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 beswungwhenever instruments or radios are changed and at least once a year.
9-39a. 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, engine running, throttle set at cruise
position and aircraft in level flight attitude. Aircraft master switch, alternator switch and all
radio switches should be in the ON position. All other cockpit controlled electrical switches
should be in the OFF position.
a. 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.
b. Head aircraft on a magnetic North heading. Adjust N-S adjustment screw until
compass reads exactly North.
c. Head aircraft on a magnetic East heading and do the same as Step b, adjusting
E-W adjusting screw.
d. Head aircraft on a magnetic South heading and note resulting South error. Adjust
N-S adjusting screw until one-half of this error has been removed.
e. Head aircraft on magnetic West and do same as Step d, adjusting E-W adjustment
screw.
f. Head aircraft in successive magnetic 30
degree headings and record compass
readings on appropriate deviation card. Deviations must not exceed + 10 on any heading.
INSTRUMENTS
Revised: 9/18/78
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