Stabilizer
The horizontal stabilizer is positioned by a single electric trim motor controlled through
either the stab trim switches on the control wheel or autopilot trim. The stabilizer may also
be positioned by manually rotating the stabilizer trim wheel.
Stabilizer Trim
Stabilizer trim switches on each control wheel actuate the electric trim motor through the
main electric stabilizer trim circuit when the airplane is flown manually. With the autopilot
engaged, stabilizer trim is accomplished through the autopilot stabilizer trim circuit. The
main electric and autopilot stabilizer trim have two speed modes: high speed with flaps
extended and low speed with flaps retracted. If the autopilot is engaged, actuating either
pair of stabilizer trim switches automatically disengages the autopilot. The stabilizer trim
wheels rotate whenever electric stabilizer trim is actuated.
The STAB TRIM MAIN ELECT cutout switch and the STAB TRIM AUTOPILOT cutout
switch, located on the control stand, are provided to allow the autopilot or main electric trim
inputs to be disconnected from the stabilizer trim motor.
Control column actuated stabilizer trim cutout switches stop operation of the main electric
and autopilot trim when the control column movement opposes trim direction. When the
STAB TRIM override switch is positioned to OVERRIDE, electric trim can be used
regardless of control column position. Manual stabilizer control is accomplished through
cables which allow the pilot to position the stabilizer by rotating the stabilizer trim wheels.
The stabilizer is held in position by two independent brake systems. Manual rotation of the
trim wheels can be used to override autopilot or main electric trim. The effort required to
manually rotate the stabilizer trim wheels may be higher under certain flight conditions.
Grasping the stabilizer trim wheel will stop stabilizer motion.
