Learjet 60 - EMER DEPRESS Switch; LDG ALT Selector; Pressurization Indicator

Pilot's Manual
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Learjet 60
remain in their last
attained position stabilizing the cabin altitude . In-
corporated into the
MAN ALT control valve is a MAN RATE control
.
The MAN RATE control
is an adjustable needle valve which restricts
the passage between the
MAN ALT valve and the outflow valves . The
rate at which the outflow valves
react to the MAN ALT control is ad-
justed by varying this
restriction .
EMER DEPRESS SWITCH
The
EMER DEPRESS switch
is an alternate-action switch
located on
the copilot's switch panel
. A guard is installed over the
switch to pre-
vent inadvertent
actuation . The switch is used to
depressurize the
cabin and increase cabin
airflow for smoke and fume
evacuation . The
EMER DEPRESS
function is available in both automatic
and manual
modes . When
EMER DEPRESS is selected, the outflow
valves receive
a signal to move
toward the full open position .
The cabin altitude will
ascend to the
aircraft altitude or 13,700 (±500) feet
(cabin altitude lim-
iter),
whichever is less . When EMER
DEPRESS mode is selected, the
EMER DEPRESS annunciator
(part of the EMER DEPRESS switch)
will be illuminated . To
de-select this mode, depress and release the
EMER DEPRESS
switch .
LDG ALT SELECTOR
The LDG ALT
selector is located on the copilot's switch
panel . The se-
lector consists of
a circular instrument graduated from
-1000 to 14,000
feet in 500-foot
increments and a setting knob used
by the crew to se-
lect the
landing field elevation . As the setting knob
is moved, the nee-
dle on the
instrument moves to show the selected landing altitude .
The selected landing
field elevation signal is supplied to the
pressuri-
zation
controller for use in determining the appropriate
cabin climb
and descent profile . The elevation of the destination
airport is selected
on
the
LDG
ALT selector prior to takeoff and checked again prior to
descent .
The LDGALT selector has no effect in manual mode .
PRESSURIZATION
INDICATOR
The pressurization indicator consists of a circular CABIN ALT instru-
ment graduated from -1000 to 20,000 feet, a circular CABIN RATE in-
strument graduated from 2000 feet per minute
down to 2000 feet per
minute up, and a digital readout to display differential pressure . All
three components of the indicator require electrical power . If power
6-28
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PM-123
Original