Piper Malibu PA-46-310P Pilot Operating Handbook page 283

SECTION 7
DESCR/OPERA TION
PIPER AIRCRAFT CORPORATION
PA-46-310P, MALIBU
NOTE
During extreme cold weather conditions,
maximum cabin heat for ground operation and
low altitude flight will be obtained when
operating with the CABIN PRESS control full
out.
7.27 BLEED AIR, CONDITIONING & PRESSURIZATION SYSTEM
Air for cabin pressure is obta~ned from the engine turbocharger
induction air system through two sonic venturi tubes. Bleed air is routed
through the bleed air heat exchanger for the temperature conditioning to
provide the desired cabin comfort level. Ram air (ambient) is routed across
the heat exchanger to cool the bl~ed air, and hot ambient air from the heat
muff is routed across the heat exchanger to heat the bleed air. Mixtures of
ambient and hot ambient may also be selected. ·
Cabin air is controlled by the CABIN PRESS control located on the
lower left side of the pilot's instrument panel. Bleed air for cabin air is
provided when the control is fully in. Ambient ventilating air is provided
~
when the control is fully out. This control operates three valves: the fire wall
shut off valve, the bleed air dump valve, and the ram air selector valve. When
fully in, the fire wall shut off valve is open. the bleed air dump valve is closed
and the ram air selector valve is positioned to route ambient air across the
bleed air heat exchanger. When the control is fully out (pull). the fire wall
shut off valve is closed, the bleed air dump valve is open anci the ram air
selector valve is posi.tioned to route ambient air into the conditioned air
ducts through the check valve and into the cabin.
Controls needed to operate the cabin pressurization system are located
on the lower left side of the pilot's instrument panel. They include the
CABIN PRESS and CABIN TEMP controls, cabin pressure and rate
controller, and CABIN DUMP switch.
For pressurized flight, set the cabin pressure controller at 1000 feet
above the airport pressure altitude, CABIN PRESS control full in and the
CABIN DUMP switch OFF. The rate of cabin change (ascent and descent)
is controlled with the rate knob (left lower corner of the cabin pressure
controller) and may be adjusted between approximately 200 and 2000 feet
per minute, as desired. Setting the rate knob arrow to the 9 o'clock position
provides a cabin rate of change of approximately 500 feet per minute. This
position gives a comfortable rate for normal operations.
REPORT: VB-1200
7-34
ISSUED: JANUARY 11, 1984