Learjet 60 - Page 90

Pilot's Manual

Learjet 60
Landing gear
extension cycle : When
the LANDING GEAR switch is
placed in the DN
position the following sequence
of events will occur :
1 .

28 VDC
will be applied to the "open"
solenoid of the door selec-
tor valve and
hydraulic pressure will be
applied to both inboard
main gear door
uplock actuators and door
actuators .
2 .
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When the
main gear doors open,
door
open
switches will com-
plete a circuit from
the LANDING GEAR
switch to the "down"
solenoid
of the gear selector
valve . Hydraulic pressure
will be
applied
to the main and
nose gear actuators and the gear
will ex-
tend
.
3 .
When the main
gear are full down, gear down switches
will
complete a circuit
from the LANDING GEAR
switch to the
"close" solenoid
of the door selector
valve
.
Hydraulic pressure
will be applied
to the inboard main gear
door actuators to raise
the gear
doors . Additionally, a gear
down safety switch will
complete a
circuit to the "down" solenoid of
the gear selector
valve to
maintain continuous hydraulic
pressure in the gear ac-
tuators .
3-8
4 .
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The gear doors are latched by uplatch
actuator spring tension .
PM-123
Original