TM 1-1510-218-CL
P-4
ELECTRIC ELEVATOR TRIM, AUTOPILOT
FLIGHT DIRECTOR OPERATION C D1
1. Pilot and copilot 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 only manual trim.
2. DISC TRIM switch – Press to second detent and
verify that electric trim disconnects and that
ELEC TRIM light extinguishes.
3. Flight Director (FD) and Radio Magnetic Indicator
(RMI) warning flags masked – Check.
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. Select HDG mode – Check.
5. Horizontal Situation Indicator (HSI) heading
marker under lubber line and vertical needle
centered – Set.
6. Engage autopilot and check controls stiff –
Check.
7. Move HSI heading marker 10° left and right and
verify that FD and control wheels respond in the
appropriate direction – Check.
