Magnetic Compass Compensation; Bank Indicator - Thrush Aircraft S2R–T660 Maintenance Manual

panel, is internally lighted, and is equipped with compensating magnets that are adjustable from the front of
the case. Covers on the face of the compass allow access to adjust the compensating magnets. The
compass should be swung and compensated at regular intervals and at any time equipment installations are
made that could cause compass deviation.

MAGNETIC COMPASS COMPENSATION

Locate the aircraft in area suitable for the method of magnetic compass compensation to be used. Close
doors and place flaps in a retracted position. Set the throttle at cruise position with engine operating. Place all
electrical switches, alternator, radio and other equipment in a mode normally used in flight and proceed with
the following:
A. Set adjustment screws of compensating magnets to zero. Zero position is when the dot on the screw
is lined up with the dot on the compass frame.
B. Position aircraft in a magnetically north direction. Adjust north-south adjustment screw until compass
reads exactly north.
C. Position aircraft in a magnetically east direction. Adjust east-west adjustment screw until compass
reads exactly east.
D. Position aircraft in a magnetically south direction. Notice the resulting south error. Adjust north-south
adjustment screw so that one-half of the error has been removed.
E. Position aircraft in a magnetically west direction. Notice the resulting west error. Adjust east-west
adjustment screw so that one-half of the error has been removed.
F. Position aircraft in successive magnetically 30-degree directions and record all errors on the
deviation card furnished with the compass.

BANK INDICATOR

The bank indicator, installed in the center of the upper instrument panels is a curved, fluid-filled tube
containing a ball. The gravitational and centrifugal forces position the ball within the tube to indicate correct
lateral altitude for the degree of banking.
Effective: 12/17/03
THRUSH AIRCRAFT INC - T660 TURBO THRUSH
AIRCRAFT MAINTENANCE MANUAL
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