CASTLEBERRY
Instruments & Avionics
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Document: 0052-1007-0002
Page 6 of 6
Revision A
8. This knob is used for quick erect. Operation of the “Pull For Quick Erect” or also labeled “CAGE’ or
“CAGING” knob is done by a steady pulling outward on the knob with a couple pounds of force until the
gyro presentation has stopped moving and in a level indication of both pitch and roll attitude and then
gently releasing the knob to return to its spring loaded position. It is normal for the gyro inertia to create or
not to create a tumbling effect during this operation depending upon its position at the time the knob was
pulled. This operation is called caging and is typically only performed upon initial start up of the gyro and
usually not required again until the next time the unit is powered up. Unusual flight conditions that may
result in the desire to cage the gyro would be if the aircraft has been in an uncoordinated turn for an
extended time duration the centrifugal forces acting on the erection system may cause leveling errors that
show up in the displayed attitude after the aircraft levels out. The gyro may be restored back to level
quickly by caging while the aircraft is known to be in a level position or allow the gyro to self correct at its
rate of approximately 3 degrees per minute until fully corrected.
The gyro must be allowed at least 30 seconds after application of power to get enough RPM to begin the
erection function. Full RPM is achieved after two to three minutes from application of power. The gyro
may be caged anytime after 30 seconds, however due to lower gyro inertia during start up the force required
to cage will be less in the 30 second to 1 minute time frame after applying power. If the gyro RPM has not
yet reached normal operational speed when gyro is caged it can be normal for the gyro to drift a few
degrees away from level and then to erect back to level as operational RPM is achieved.
Even though the gyro looks level after caging, it is really only level at this time if the aircraft was perfectly
level when the caging was done. Immediately after caging, the gyro will begin to settle towards true level.
By being somewhat close to level when caging the gyro, it should settle to true level in a short period of
time producing the “Fast Erect” function.
Caution:
Caging the gyro by pulling the “Pull For Fast Erect” knob while in flight when the aircraft is not
level will cause the gyro to be incorrect until it can settle back to true level.
