TM 55-1510-220-CL
ELECTRIC ELEVATOR TRIM AND AUTOPILOT/FLIGHT
DIRECTOR OPERATION
1.
Pilot's and copilot's PITCH TRIM switches - Press to
NOSE UP and NOSE DN positions, singularly and in
pairs. Check that trim wheel moves in proper direction
and operates only when trim switches are pressed in
pairs. Any deviation requires that electric elevator trim
be turned off and flight conducted using manual trim.
2.
DISC TRIM switch - Press to second detent and verify
that
electric
trim
disconnects
and
ELEV
TRIM
annunciator light (in pedestal) extinguishes.
3.
Flight director (FDI) and Radio Magnetic Indicator (RMI)
warning flags - Check masked.
NOTE
Since the pressure of airflow that normally
opposes movement of control surfaces is absent
during preflight check, it is possible to get a hard
over control surface deflection if an autopilot
command is allowed to remain active for any
appreciable length of time. Move turn knob and
pitch
thumbwheel
only
enough
to
check
operation, then return them to the center
position.
4.
Autopilot mode selector panel - Select HDG mode.
5.
Horizontal Situation Indicator (HSI) - Set heading
marker under lubber line.
6.
Autopilot - Engage Check that controls are stiff and that
AP ENG, HDG, and AIL HI TORQUE annunciator lights
illuminate.
P-5
