Flaps - BOMBARDIER LEARJET 40 Pilot's Manual

FLAPS

The airplane's single-slotted Fowler flaps are electronically controlled
and operated by a hydraulic motor (flap power unit). Each flap panel,
one on each wing, has three safe-life flap tracks and is driven by two
screw jack actuators. A flexible drive shaft transfers power from the hy-
draulic motor to each flap actuator. The flap control lever is located on
the center pedestal and is recessed to prevent inadvertent operation.
The flap control lever has settings at 0° (up), 8°, 20° and 40° (down). To
select a new flap position, the flap control lever is moved directly to the
desired setting. Flap position is controlled by a microprocessor based
controller (Flap Control Unit). The Flap Control Unit receives position
command information and an arming signal from the flap control lever
in the cockpit. It then provides the electrical arming and control signal
to the arming solenoid valve located in the flap power unit and receives
a feed-back signal from sensors mounted on the outboard actuator of
each flap panel. When flaps are extended or retracted in flight, the con-
figuration trim system automatically applies the appropriate amount
of pitch trim to compensate for the pitching moment caused by flap re-
positioning.
The Flap Power Unit (FPU) is located under the center wing and con-
tains the hydraulic motor, a servo control valve, an arming solenoid
valve and a pressure switch. The servo valve responds to electrical sig-
nals from the flap control unit and meters hydraulic pressure to the ex-
tend or retract side of the bidirectional hydraulic motor. The arming
solenoid valve must be energized open by the flap control unit before
hydraulic pressure is available to the servo valve. The pressure switch,
located upstream of the servo valve, monitors system pressure between
the arming solenoid valve and the servo valve. If pressure is not avail-
able on flap selection, flaps will be inoperative, but if pressure is avail-
able without a selection command, the FPU will show a fault and the
flaps will operate in a degraded mode, i.e. the flaps may deploy at a
reduced speed when selected. These will cause the following CAS illu-
minations in order described above.
The following CAS illuminations are specific to the flap system:
CAS
FLAPS FAIL
FLAPS FAULT
PM-132A
Color
Amber The flap system has failed and the flaps are
inoperative.
Amber The flap system is operating in a degraded
mode.
Pilot's Manual
Description
5-7