Learjet 60 - Mach Trim; System Test Switch -Spoiler Reset Function; Trim Systems

Pilot's Manual
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SYSTEM
TEST SWITCH
-
SPOILER RESET FUNCTION
The rotary-type
system test switch, located
on
the center instrument
panel, is used to test the spoiler system .
During flight, the SPOILER RESET position is used to reset the spoiler/
spoilmon system
in the event of a
malfunction
. Should the monitor dis-
able spoiler/ spoileron mode (SPOILER MON light illuminated) and
the fault clears, the system may be enabled by momentarily placing the
system test switch in the SPOILER RESET position . If the system is re-
set the
SPOILER
MON
light
will
extinguish . If the
spoiler
jspoiieron
system cannot be reset, the
SPOILER MON
light will remain
illuminat-
ed and normal spoiler or spoilerons will not be available in flight .
During ground operations, the switch is used during the spoileron and
autospoiler test sequence to verify system operation . Placing
the sys-
tem test switch in the SPOILER RESET position and depressing the
PRESS TEST button in the center of the switch will simulate a
malfunction .
TRIM SYSTEMS
MACH TRIM
The Mach trim system
provides
automatic pitch trim in
response to
Mach changes
to increase longitudinal stability and counteract the cen-
ter-of-lift movement at speeds above approximately 0 .70 MI if the
autopilot is disengaged or inoperative . The system consists of
a
corma-
puter, a pitch trim followup,
the MACH TRIM annunciator light, and
associated aircraft wiring . The Mach trim computer receives
Mach data
from the air data computers . The Mach trim system utilizes the primary
motor of the horizontal-stabilizer pitch-trim actuator to affect trim
changes . The Mach trim
computer operates on 115 VAC supplied
through
the 1-amp MACH TRIM circuit breaker and 28 VDC
supplied
through
to 3-amp PRI
PITCH
TRIM circuit breaker on the pilot's cir-
cuit breaker panel, The Mach trim system is inoperative during E14ER
BUS mode
.
During flight, with the autopilot disengaged or inoperative, the Mach
trim system will automatically engage at approximately 0 .70 Nfi . As the
aircraft Mach number changes, the change is sensed by the air data
computers and transmitted
to the Mach trim
computer . If the
aircraft is
not retrimmed to compensate for the Mach change, the Mach A& com-
puter
will command
the appropriate pitch trim change (nose up for in-
creased Mach and nose down for decreased Mach) through the
horizontal-stabilizer
pitch-trim actuator . A followup on the horizontal
stabilizer will transmit a horizontal stabilizer position signal
to the
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PM-123
Change 4