ZENAIR CH2000 SERVICE MANUAL
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DIRECTIONAL GYRO INDICATOR - Fig. 22
GENERAL
The directional gyro is a flight instrument incorporating an air driven gyro stabilized in the
vertical plane. The gyro is rotated at high speed by lowering the pressure in the airtight
case and simultaneously allowing atmospheric air pressure to enter the instrument against
the gyro buckets. Due to gyroscopic inertia, the spin axis continues to point in the same
direction even though the aircraft yaws to the right or left. This relative motion between
the gyro and the instrument case is shown on the instrument dial which is similar to a
compass card. The dial, when set to agree with the airplane magnetic compass provides a
positive indication free from swing and turning error.
TROUBLESHOOTING See following table:
DIRECTIONAL GYRO INDICATOR
Trouble
Cause
Remedy
Excess drift in either
direction.
Excessive vibration with
amplitude more than 0.006
inch.
Insufficient vacuum.
If vacuum below 3.75 inch
Hg, check for the following:
a. Regulator improperly
adjusted.
Check shock mounts.
a. Adjust - see Fig. 22.
b. Incorrect gauge reading.
c. pump failure
d. Vacuum line kinked or
leaking.
Defective instrument.
b. Recalibrate.
c. Repair or replace.
d. Check and repair.
Check for collapsed inner
wall of hose.
Replace instrument.
Dial spins continuously.
Defective mechanism.
Replace.
9.10
3 Apr 95