The main gear hydraulic actuator also serves as a
side brace when the gear is extended. It features
an integral downlock mechanism that can be
unlocked only by hydraulic pressure on the
retract side; therefore, no downlock pins are pro-
vided. Each main gear torque arm link actuates a
squat switch.
The main gear is hydraulically held in the
retracted position and is enclosed by an outboard
and an inboard door. The outboard door is
mechanically linked to, and travels with, the
gear. The inboard door is hydraulically actuated,
electrically sequenced by microswitches, and
held retracted by a spring-loaded, overcenter
uplatch that is released by a hydraulic actuator.
With a full fuel load and no passengers or
baggage aboard, 3 to 3 1/2 inches of bright
surface should be visible on the lower portion of
the main gear strut.
Main Gear Wheel and Tires
Each main gear wheel incorporates a fusible
plug that prevents tire blowout caused by exces-
sive heat resulting from hard braking. Tires must
be monitored closely when tread has worn to the
base of any groove at any location. Tires must be
changed any time cord is exposed.
Nose Gear
The nose gear consists of an air-hydraulic shock
strut incorporating a self-centering device, a
nosewheel steering actuator, and mechanically
operated doors (Figure 14-4).
14-4
FOR TRAINING PURPOSES ONLY
LEARJET 20 SERIES PILOT TRAINING MANUAL
FlightSafety
international
INBOARD DOOR
UPLOCK ROLLER
Figure 14-3.
Main Gear
Figure 14-4.
Nose Gear