PNEUMATICS
AIR CONDITIONING
AND PRESSURIZATION
AIRPLANE
OPERATIONS
MANUAL
2-14-05
Page
4
Code
01
REVISION 32
The functional logic opens automatically the CBV and both HSVs and
closes the left air conditioning pack below 24600 ft, whenever the anti-
icing system is operating, on airplanes Pre-Mod. SB 145-36-0028.
On airplanes equipped with a pressure regulating and shutoff EBVs
(Post-Mod. SB 145-36-0028), the functional logic also opens both
HSVs and closes one pack below 24600 ft, but does not open the CBV
if the anti-icing system is operating.
Air Conditioning ON Ice Protection ON
Airplanes Pre-Mod.
SB 145-36-0028
Cross-bleed Closed Cross-bleed Open
Airplanes Post-Mod.
SB 145-36-0028 or
equipped with an
equivalent modification
factory incorporated.
Cross-bleed Closed
Bleed air from the APU, that is used primarily as an auxiliary pneumatic
source, is provided in the left side of the pneumatic system to supply
the air conditioning and engine starting either on ground or inflight.
An APU Bleed Valve (ABV), which is electrically controlled through the
APU Bleed Button and pneumatically-actuated, provides APU bleed
control.
The pneumatic system functional logic automatically closes the ABV
whenever any engine is supplying bleed air to the left pneumatic side.
An APU Check Valve is installed downstream of the APU bleed valve.
A ground pneumatic source connection, including a check valve, is
installed on the right side of the pneumatic system. Its main purpose is
to supply pressurized air to start the engines.
Leak detectors (thermal switches) are installed along all the pneumatic
lines. Should a duct leakage occur, these detectors activate a warning
message in the EICAS.
Should an intense hot air leakage occur three Massive Leakage
Detectors (thermal switches – formerly located at the pre-cooler and
currently located in the rear electronic compartment area) will close the
EBV of the affected side, as well as the CBV, ABV and HSV.
For Airplanes Post-Mod. SB 145-36-0030, all detectors, Massive Leak
Detectors and Leak Detectors also can close the EBV, CBV, HSV and
ABV if a duct leakage occur. All detectors activate a warning message
in the EICAS in case duct leakage.
Bleed temperatures upstream and downstream of the pre-cooler are
monitored through temperature sensors. Temperature downstream of
the pre-cooler is presented on a vertical bar indication on the MFD.
To Next Page
Loading...
