Learjet 20 Series Pilot Training Manual page 324

Pitch Trim Monitor Switch—This switch is in-
stalled on the pedestal switch panel and is
used to test the autopilot disengage function
when an improper electrical signal is intro-
duced to the pitch function. The switch has
three positions—DOWN, OFF, and UP, and is
spring-loaded to the OFF position.
Roll Monitor Switch (when installed)—This
switch is installed on the pedestal switch panel
and is used to test the autopilot disengage func-
tion when an improper electrical signal is in-
troduced to the roll function. The switch has two
positions—hold to TEST and a spring-loaded
OFF position.
Autopilot Roll Monitors—The roll monitors
will disengage the autopilot if the bank angle
exceeds 40° or if the roll rate exceeds 20° per
second for more than approximately one-half
second. When either monitor disengages the
autopilot, the disengage tone will sound.
Autopilot Pitch Trim Monitor—The autopilot
maintains pitch trim using the airplane's emer-
gency pitch trim motor. Whenever the autopi-
lot is engaged and secondary trim runs in a
direction opposite the elevator servo force, the
monitor will disengage the autopilot and the dis-
engage tone will sound.
Autopilot Pitch Monitor (24 Series)—With the
autopilot engaged, the autopilot pitch moni-
tor will cause the elevator to streamline (null
servo force) whenever the g level reaches 0.45
g. The pitch axis does not disengage but will
maintain the elevator streamlined. Previously
engaged pitch modes will remain engaged.
When the airplane is again above the g limit,
the pitch axis will resume elevator inputs.
Au t o p i l o t / S t i c k N u d g e r / S t i c k P u l l e r
Interface—If the autopilot is engaged and the
stick nudger or puller actuates, any selected
pitch mode will disengage and the autopilot
will maintain a synchronous standby mode
until the stick nudger or puller releases. When
the stick nudger or puller releases, the autopi-
lot will maintain the existing pitch attitude.
Autopilot Effort Indicators—An autopilot ef-
fort monitor senses the autopilot output signals
for pitch, roll, and yaw. These are displayed on
LEARJET 20 SERIES PILOT TRAINING MANUAL
FOR TRAINING PURPOSES ONLY
the autopilot effort indicators (Figure 16-9)
labeled "EL" (pitch), "AIL" (roll), and "RUD"
(yaw). Deflection from indexed positions in-
dicates that force is being applied to the asso-
ciated autopilot servoactuator.
Figure 16-9. Autopilot Effort Indicators
FLIGHT CONTROLLER
OPERATION
Lights—The autopilot amber OFF light is il-
luminated anytime the autopilot has DC power
available and is not engaged. The autopilot
green ON light is illuminated only when the au-
topilot pitch and/or roll axes are engaged. When
the engage button or any mode button is de-
pressed, a light inside the button will illuminate
and extinguish when the button is disengaged.
Engage Button—The autopilot ENG button
engages the pitch and/or roll axes and main-
tains heading using the pilot's HSI (called the
HDG hold function) and maintains wings level.
Commands to the AFCS are initiated by the roll
turn knob and pitch command wheel. The au-
topilot can be disengaged by any of the follow-
ing buttons or switches, and a tone will sound
indicating disengagement.
• Either four-way trim switch (up or down)
(UP, DOWN, LWD, RWD with the arm-
ing button engaged on airplanes with
two-speed trim system)
• Either wheel master button
FlightSafety
international
16-7