On models 23 and 24, a single yaw damper sys-
tem provides yaw stability. Model 25 airplanes
have a dual yaw damper system.
A dual stall warning system provides an indica-
tion of impending stall by vibrating the control
column and, if no corrective action is taken,
induces a forward control column movement to
reduce the airplane angle of attack.
A Mach overspeed warning system warns of
overspeed and on all airplanes induces an aft
control column movement to raise the nose of
the airplane when M
MO
is exceeded. Model 23
airplanes have overspeed warning but do not
have a stick puller.
All flight control surfaces are shown in
Figure 15-1.
A flight controls gust lock (Figure 15-2) is pro-
vided to prevent wind gust damage to the prima-
ry flight control surfaces. When installed, the
lock holds full rudder and ailerons, and full-
down elevators.
LEARJET 20 SERIES PILOT TRAINING MANUAL
FlightSafety
international
15-2
FOR TRAINING PURPOSES ONLY
HORIZONTAL
STABILIZER
ELEVATOR
FLAP
AILERON TRIM TAB
AILERON BALANCE TAB
(BOTH WINGS)
AILERON
VERTICAL STABILIZER
RUDDER
RUDDER
TRIM TAB
SPOILER
Figure 15-1. Flight Control Surfaces
