TM 55-1510-222-MTF
PROCEDURE
TROUBLESHOOTING
REFERENCE
BEFORE TAXIING (CONT)
Operation of the electric trim system should
occur only by movement of pairs of switch-
es. Any movement of the elevator trim
wheel while depressing only one switch ele-
ment denotes a system malfunction. The
electric elevator trim control switch must
then be turned OFF and flight conducted by
operating the elevator trim wheel manually.
Do not use autopilot.
(1) Check pilot and copilot in-
dividual trim switch ele-
ments for no movement of
trim, then check proper op-
eration of both elements.
(2) Check pilot switches over-
ride copilot switches while
trimming in opposite direc-
tions, and trim moves in
direction commanded by
pilot.
c. Check pilot and copilot trim
disconnects autopilot while ac-
tivating trim.
d. Elevator trim switch - OFF
then ON (ELECT TRIM OFF
annunciator extinguishes).
8. Avionics - Check and set as re-
quired.
9. INS - NAV mode, if on.
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