User manual

Piper PA-31T Cheyenne X
Aerosoft GmbH 2007
90 91
90 91
air outlets. When the control is in the OUTSIDE AIR position, the air
is not needed for pressurization. Air is then routed below the cabin
floor and overboard. During ground operations, to prevent fumes from
other aircraft entering the cabin, the control may be placed in the
RECIRCULATED AIR position. In this position, no outside air enters the
system. Restrict continuous operation in the recirculated air position to
15 minutes.
Before takeoff, set cabin altitude 500 feet above the field pressure
altitude, using the cabin altitude controller (4). Cabin pressurization
will begin as the cabin passes through the altitude selected. Cabin
altitude will remain at the selected altitude until maximum cabin diffe-
rential (5.5 PSI) is reached, at which time the cabin altitude will begin
to climb, until at 29.000 feet (IIXL only: 31.000 feet) pressure altitude
the cabin pressure altitude will be 10.000 feet (Garret: 11.100 feet).
For flights below an airplane altitude of 13.000 feet (Garret: 12.000
feet), the cabin altitude control (4) should be left at the takeoff setting.
For flights above 13.000 feet (Garret: 12.000 feet) (at which point
maximum differential will be exceeded) set the cabin altitude controller
(4) to the cruise altitude +500 feet and adjust the cabin rate of climb
(1) as desired. It is recommended that this setting be made during
climb out after the controller has captured isobaric control.
To descend for landing be certain that the selected cabin altitude is
higher than the pressure altitude of the landing field. Shortly after
descent is initiated, set the cabin altitude controller (4) to 500 feet
above the pressure altitude of the landing field and adjust the rate
control (3) high enough to allow the cabin to descend to the landing
setting before the aircraft descends to that altitude. For normal
descent, the rate knob (3) should be at the twelve o’clock position. A
higher setting should be selected for rapid descent, so that the aircraft
altitude does not catch up with the cabin altitude.
To the immediate left of the cabin altitude selector and rate of change
controls are instruments to simplify setting the system and to monitor
system operation. The cabin altitude instrument (2) indicates the cabin
altitude in feet, and the cabin rate of change gauge (1) indicates the
rate at which cabin altitude is changing in feet per minute. A diffe-
rential pressure gauge, which is incorporated in the face of the cabin