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operates between a maximum of 600 fpm
climb, to 375 fpm descent rate.
A continuous self-test is performed by the
CPC. Malfunctions will be annunciated on
the CAS. If differential pressure is out of the
normal range, the CPC will flash the out-of-
limits values on the LCD and display the “CAB
DELTA P” CAS message.
If a fault is detected in either channel of the
CPC, a white “L or R CABIN PRESS FAIL”
message will be displayed on the CAS. If the
fault is in the primary (left) channel, the sec-
ondary (right) channel will assume control
and be active in the automatic mode. If the fault
is in the secondary channel, the primary chan-
nel will remain in control but the CPCS dis-
play will blank.
If both channels of the controller fail, an amber
“LR CAB PRESS FAIL” message is displayed
on the CAS, the LCD blanks and displays for
c a b i n p r e s s u r i z a t i o n p a r a m e t e r s o n t h e
EICAS/MFD become amber dashes. With both
channels failed, neither the automatic nor
manual mode of pressurization control is avail-
able and the outflow valves close until the
maximum Delta P of 9.7 psid is reached. The
airplane will land pressurized unless pres-
surization can be turned off before landing.
If DAU 1A channel has failed, a “LR CAB
PRESS FAIL” amber CAS will annunciate
even though the cabin pressurization system
has not failed. This CAS message will extin-
guish when DAU 1B channel is selected.
Selection of DAU B reversion will result in an
erroneous “FDR FAIL” white CAS message.
In addition to providing for pressurization
control and indications, the CPC also pro-
vides discrete outputs for pressurization re-
lated CAS messages, activation of emergency
pressurization (9,500/14,500 feet), activation
of the cabin altitude voice message (10,000
feet), and deployment of the passenger oxy-
gen system (14,500 feet). These output signals
are independently generated by the left and
right channels of the CPC.
PRESSURIZATION
CONTROLLER POWER
SOURCE
The two channels of the CPC have indepen-
dent electrical power sources. The left chan-
nel receives 28 VDC from the Left Main Bus
through the L PRESS circuit breaker in the
Environmental group on the pilot’s circuit
breaker panel. The right channel of the con-
troller receives 28 VDC from the Emergency
Battery Bus through the R PRESS circuit
breaker located in the Environmental group on
the co-pilot’s circuit breaker panel.
The left channel normally provides the pres-
surization control functions, but either chan-
nel can provide all automatic or manual
pressurization control functions with power
failure to the other channel.
If dual generator failure occurs, the L Main Bus
is automatically shed and the right channel,
powered by the Emer Batt Bus, will assume
pressurization control. Failure of a single
channel of the pressurization controller will
cause a white “L or R CABIN PRESS FAIL”
CAS message to be displayed.
If the power fails to the right channel of the
CPC or the R PRESS circuit breaker opens, the
CPC display goes blank. It will be necessary
t o u s e t h e S U M RY / E C S d i s p l a y o n t h e
EICAS/MFD to monitor cabin pressurization
in this case.
If the Emer Batt Bus is the only remaining
bus powered due to electrical failure (both
generators and main batteries failed), the sec-
ondary channel of the CPC will be powered.
It will be in the manual mode since neither
ADC is powered in this case, but “ON” will
not be illuminated in the MANUAL PRESS
S/I. It will be possible to control the cabin
pressure in manual mode operation, but it may
be necessary to use a flashlight to view the CPC
display since it will not be lighted in this case.
12-6
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
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