must be within the takeoff bands for takeoff.
When the airplane is on the ground, digital dis-
plays of trim will have a white box around
them if the trim is not within the takeoff band
and a white “TAKE OFF TRIM” message is
posted on the CAS (Table 15-1).
If power is advanced to MCR or above for
takeoff and the trim is not within the takeoff
band on all three trim indicators, the “CON-
FIGURATION” voice warning will sound, and
the “TAKEOFF TRIM” CAS message turns
red. The digital trim indication for the out-of-
trim axis turns red and is highlighted with a red
box. If the FLT system schematic is selected
for display, the affected digital trim indica-
tion turns red and is enclosed with a red box
and the pointer on the analog scale turns red.
The pitch trim position is determined by sen-
sors in both pitch trim actuator motor assem-
blies. If the trim position indicated through the
DAUs to the IC-600s is in disagreement, the
IC-600 will generate an white “PIT TRIM
MSCMP” CAS message. If this message is
being displayed while the airplane is on the
ground and the thrust levers are moved to
MCR or higher, the takeoff “CONFIGURA-
TION” voice message will sound and the CAS
message will be red.
Pitch, aileron, and rudder trim indications are
available on page 2 of the backup engine/sys-
tem pages on the RMU (Figure 15-15).
FLAPS
General
The flaps are electrically controlled and hy-
draulically actuated. There are two flap seg-
ments, one on each wing (Figure 15-17). Each
flap is supported by three tracks, positioned
by cantilever rollers attached to the rear spar
mounting structure. Extension and retraction
of the flaps is achieved by two jackscrew ac-
tuators per flap section. Flap motion is a com-
bination of aft movement to increase lift and
downward tilting to increase drag.
Uncommanded retraction due to airloads, vi-
bration, etc., is prevented by the irreversibil-
ity of each actuator.
The system used to position the flaps is a mi-
croprocessor based controller (Flap Control
Unit). The controller receives position com-
mand information and an arming signal from
the flap selector lever in the cockpit. It then
provides the electrical arm and control signals
to the arming solenoid valve and the servo
valve located in the flap power unit and re-
ceives feed-back signals from sensors mounted
on the outboard actuator of each flap panel
(Figure 15-17).
The flap power unit is located under the cen-
ter wing and contains the flap drive motor, a
servo control valve, an arming solenoid valve
and a pressure switch. The servo valve re-
sponds to electrical signals from the flap con-
trol unit and meters hydraulic pressure to the
extend or retract side of the bi-directional flap
drive motor. The arming solenoid valve must
be energized open by the flap control unit be-
fore hydraulic pressure is available to the
servo valve. The pressure switch signals the
flap control unit if pressure decreases to 1,200
psi. The flap control unit will close the arm-
ing solenoid valve in this case.
Flexible drive shafts, routed along the wing
rear spar, transmit the rotary motion of the
flap drive motor to the input shaft of each
ballscrew actuator (Figure 15-17). Two Rotary
Variable Differential Transformers (RVDTs)
mounted on the outboard side of each out-
board flap actuator provide position infor-
mation to the flap control unit and the flap
position indicating unit (Figure 15-17)
15-21
FOR TRAINING PURPOSES ONLY
LEARJET 45 PILOT TRAINING MANUAL
FlightSafety
international
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