Gulfstream G200 User manual

TRIM SYSTEM
HORIZONTAL STABILIZER TRIM SYSTEMS
General
The variable incidence horizontal stabilizer serves for longitudinal
(pitch) aircraft trim. Two independent electrical trim systems ensure the
ability to trim the aircraft if one system fails.
The stabilizer travel is +2.5° to -9.5° which covers the entire flight and
cg envelopes trim requirements.
Normal System
Trim switches, located on top outboard side of pilot and copilot control
wheels, control normal operation. When either trim switch is moved UP
or DOWN, actuator's primary motor energizes to retract or extend the
actuator to desired position. Limit switches are incorporated in the
actuator to restrict stabilizer travel.
Pitch trim tone (from EICAS) sounds whenever normal system
operates. Autopilot trim is also achieved through the normal system.
Mach Trim
Mach trim is operative when autopilot is disengaged. Mach trim is
activated when ADC mach data indicates that longitudinal trim is
necessary (0.79 Mi).
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Override System
When the primary drive control fails to operate, pressing PITCH TRIM
REL. button, located on the control wheel, provides the following
functions:
• Disconnects power from trim unit primary channel.
• Powers up to the secondary channel.
• Powers up the override switch.
• Disconnects the autopilot
When PITCH TRIM REL. button is pressed, the RESET pushbutton
illuminates and then by pressing the HORIZ TRIM switch in NOSE UP
or NOSE DN position, the secondary drive control of trim actuator is
energized, causing the horizontal stabilizer to move in desired
direction. Autopilot is inoperative when override system is operating.
When RESET pushbutton is pressed, the secondary drive control
deenergizes (light - out). Power is restored to the primary drive system.
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LATERAL TRIM SYSTEM
Lateral trim is achieved by the ailerons. An electrical trim actuator
mounted near the artificial feel system operates the ailerons through
the normal control system. The aileron travel, when operated by the
trim system, is 1/3 of full aileron travel.
Aileron trim is controlled by a switch located on the pedestal alongside
the rudder trim switch.
DIRECTIONAL TRIM SYSTEM
Directional (rudder) trim is accomplished by moving a trim tab on the
rudder. This tab is operated by two mechanically interconnected
electrical actuators, each protected by separate circuit breaker.
The rudder trim control switch is located on the pedestal alongside the
aileron trim switch.
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TRIM SYSTEMS CONTROLS AND INDICATORS
Pitch Trim Switches (2) - Located on each outboard prong of pilot and
copilot control wheels. The switches have three positions:
Center - Stops horizontal stabilizer trim operation.
NOSE DOWN - Momentary position to trim nose down. Spring
loaded to center.
NOSE UP - Momentary position to trim nose up. Spring loaded to
center.
NOTE
Pilot pitch trim switch has priority over copilot
switch.
PITCH TRIM REL. Button - Located on pilot control wheel inboard
prong. Pressing the button deactivates normal system
and arms OVRRD system; RESET OVRRD button light
comes on.
HORIZ TRIM OVRRD Switch - Controls the override trim system in the
same manner the normal pitch trim switches control the
normal system.
RESET OVRRD Button - When pressed, the override system is
de-energized and normal system is armed. It lights up
when PITCH TRIM REL. button is pressed.
AILERON Trim Switch - Has three position as follows:
Center - Stops aileron trim operation.
RW DN - Momentary position. Moves control wheel to right (right
roll).
LW DN - Momentary position. Moves control wheel to left (left roll).
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RUDDER Trim Switch - Has three positions as follows:
Center - Stops rudder trim operation.
NOSE R - Momentary position. Trims rudder to right.
NOSE L - Momentary position. Trims rudder to left.
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