sage and red GEAR CWP annunciator will re-
main illuminated and the voice message will
continue as long as the condition exists.
The gear warning/caution system is tested by
selecting the GEAR position on the airplane
system test switch and depressing the push-to-
test button. See Table 14-2 for a list of gear
warnings test indications.
MAIN GEAR COMPONENTS
General
Each trailing-link main gear consists of a con-
ventional air-hydraulic shock strut, dual
wheels, scissor links, weight-on-wheels switch
(squat switch), gear actuator, inboard and out-
board doors, and an inboard door actuator.
(Figure 14-4).
The main gear hydraulic actuator also serves
as a side brace when the gear is extended. A
mechanical key lock type downlock, inside
each gear actuator, holds the gear in place
after hydraulic pressure has been relieved or
lost. Once in place, the downlock can only be
unlocked by applying hydraulic pressure to the
retract side of the actuator (Figure 14-11, page
14-11).
As each main gear strut extends after takeoff
the squat switches open, transitioning ground
mode signals into air mode signals. Since strut
extension depends on the air charge in the
strut, proper strut inflation is an important
consideration. The shock struts are serviced
to a specified pressure with the airplane on
jacks. When the airplane weight is on the
struts, the amount of strut extension varies
with the airplane load.
The main gear are normally held in the ex-
tended position using positive hydraulic pres-
s u r e . W h e n r e t r a c t e d , t h e m a i n g e a r a r e
enclosed by the inboard and outboard doors.
The outboard doors are mechanically con-
nected to, and move with the gear struts. The
inboard doors are electrically controlled and
hydraulically actuated (Figure 14-5). When the
gear are fully retracted and the inboard gear
doors are closed, the doors are held closed by
mechanical uplatches. The uplatches are nor-
mally released by hydraulic pressure, but may
be released by cable in the event of a hydraulic
system failure.
When the main gear are retracted, they are
initially held up by hydraulic system pres-
sure. After the inboard gear doors close and
lock, hydraulic pressure is removed from the
retract side of the main gear actuators and the
14-7
FOR TRAINING PURPOSES ONLY
L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
FlightSafety
international
L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
FlightSafety
international
Figure 14-4. Main Gear Components
Figure 14-5. Inboard Door