Learjet 60 - System Test Switch - Stall Warning Function

Learjet 60

Pilot's Manual
ANGLE-OF-ATTACK INDICATORS
The angle-of-attack indicators, located on the pilot's and copilot's in-
strument panels, translate signals from the stall warning computer-am-
plifier into a visual indication of angle-of-attack . These indicators
present
normalized
angle-of-attack information
for
all flap settings on
a scale from 1 .0 (max lift) to 0 (zero lift) . The left stall warning system
utilizes the pilot's angle-of-attack indicator and the right stall warning
system utilizes the copilot's angle-of-attack indicator . Each indicator
face is divided
into three segments as
follows
: green -safe,
yellow -caution/shaker, and red -warning .
In addition to angle-of-attack indicators, low speed cues are displayed
on the left side of
the
PFDs
. They indicate
impending stall
speed (speed
at which the `stick shaker triggers), and a 1 .3Vs approach cue . These
cues are only visual cues that reflect AOA data and' are not intended to
replace the actual stall warning system .
STALL WARNING LIGHTS
The
red L and R STALL warning lights, located in the glareshield an-
nunciator panel,
are installed to indicate
impending stall
or a system
malfunction . During flight operations, the lights will illuminate and
flash when the shaker is actuated
.
The lights are pulsed at the same fre-
quency and duration as the shakers ; therefore, the flash frequency will
increase as the angle-of-attack increases from initial shaker actuation .
At or just prior to the angle-of-attack pointer entering the red segment,
the flash frequency is sufficient
to cause
the lights
to
appear
steady .
SYSTEM TEST SWITCH - STALL WARNING FUNCTION
The rotary-type
system test switch, located on the center instrument
panel,
is
used to test the left and right stall warning systems
.
Each
sys-
tem is individually tested through the L STALL and R STALL positions
of the system test switch . The test is initiated by rotating the system test
switch
to
L
or
R STALL
(as applicable) and then depressing the switch
PRESS TEST button . When the test sequence is initiated, the corre-
sponding angle-of-attack indicator pointer will begin to sweep from
the
green segment toward the red segment . As the pointer passes the
green-yellow margin,
the stick-shaker
will
actuate, Master
WARN
lights will illuminate, and the applicable STALL light will begin to
flash . Shaker actuation is made evident by high frequency vibration of
the control
column .
PM-123
Change 4
5- 21