Pilot’s Operating Handbook Section 7
EXTRA 500 Description of Airplane and Systems
7.20 Environmental (Bleed Air) Control System
Note For system overview refer to Figure 7-17
7.20.a General
Engine bleed air is used for cabin pressurization. A small
portion of the compressed air exiting the engine compressor is
extracted from the engine by means of two bleed ports. These
ports incorporate orifices to limit bleed air (and therefore
power) loss in case of rupture or severe leakage of the airplane’s
bleed air ducting. The main portion of the extracted bleed air is
used for cabin pressurization.
A shut off valve enables the pilot to shut off cabin bleed air.
This valve is operated by the switch
ENV AIR located on the left
side panel (see
Figure 7-16).
Environmental (cabin) bleed air should be switched off before
engine shut down to configure the aircraft for the next engine
start with bleed air shut off.
Environmental bleed air should also be shut off in some
emergency conditions as:
• contaminated air entering cabin,
• imminent cabin overpressure, or
• in case other measures failed to terminate a BLEED
OVERTEMP warning, indicated on the annunciator panel.
In case ENV AIR is switched off, ram air, taken from the oil
cooler air inlet is directed to the cabin. Max. ram air flow will
be achieved with the
PRESS switch on the CABIN section (see
Figure 7-16) set to the DUMP position.
Note Pressurized flight is not possible with the ENV AIR switch in
OFF position.
26. January 2011 7-57
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