interconnects the control chambers of the out-
flow valves (Figure 12-3).
When power is applied to the airplane elec-
trical system, the CPC performs a functional
check. Once the functional check is success-
fully completed, the system is in the auto-
matic mode. The left channel will normally
control the pressurization in the automatic
mode but will relinquish command to the right
channel if a fault is detected in the left chan-
nel. Selection of the channel to be active is not
a crew option; however, manual can be se-
lected on the currently active channel.
The CPC utilizes crew input from the control
panel along with airplane altitude and baro-
metric correction and true airspeed from the
air data computers, cabin pressure, left thrust
lever position (MCR), landing gear switch po-
sition and squat switches along with internal
program logic to perform its functions.
In the automatic mode, the controller uses ei-
ther the climb or descent schedule to maintain
the appropriate cabin altitude inflight. When
the airplane is level, the CPC holds the cabin
altitude at the climb schedule value. The air-
plane has to deviate by +
200 feet from the es-
tablished altitude before the system allows
changes in cabin pressure. When the airplane
descends 1,000 feet, the CPC initiates the de-
scent schedule.
The rate-of-climb and descent is non-se-
lectable in the automatic mode. The controller
12-5
FOR TRAINING PURPOSES ONLY
LEARJET 45 PILOT TRAINING MANUAL
FlightSafety
international
9,500 FT.
14,500 FT.
14,500 FT.
To Next Page
Loading...