PILOT’S OPERATING HANDBOOK
SECTION 7
DESCRIPTION
Edition 0 -- October 31, 2013
Rev. 1
Page 7.9.2
To bleed air from the engine
The Engine Bleed Air System is based on 2 engine bleed ports operation. The normal operation is performed on
P2.5 engine port as far as the pressure or temperature available at this port is able to comply with the needs. If one
of these conditions is not fulfilled, the system automatically switches to P3 engine bleed port. The switching back to
P2.5 supply is automatically performed as far as the conditions on P2.5 are restored to adapted values.
The sensor (IPPS) measures continuously the pressure at the P2.5 pressure port and sends the value to the
Global Air System Controller (GASC) which manages the ports switching on condition with the Shut Off Valve
(SOV). A Non Return Valve (NRV) secures the P2.5 pressure port when the P3 pressure port is opened.
To ensure a controlled airflow in the cabin
The bleed flow control operation, including bleed AUTO/bleed OFF/RST controls, is ensured by the FCSOV driven
by the GASC.
To adjust the temperature of the bleed air
The bleed air outlet temperature control is ensured by the By-Pass Valve (BPV) in association with the Main Heat
Exchanger (MHX).
The temperature measurement loop given by the Inlet Temperature Sensor (ITS) and the 2 Ventilated
Temperature Sensors (CKVTS, CBVTS) sends the value to the GASC which compares them with the set
temperature and manages the BPV position. The BPV derives a part of the bleed air through the MHX to cool it and
mix it to the remaining air.
The Engine Air Bleed System is supplied by ”BUS 2” bar and protected by the ”CAB BLEED” CB60 circuit breaker.
DUAL ZONES ENVIRONMENTAL CONTROL SYSTEM
The Environmental Control System is based on two independent air circuits. The heating circuit uses the controlled
temperature bleed air. The cooling circuit is based on a Vapor Cycle System (VCS).
The Environmental Control System is designed to ensure the following functions :
-
Cockpit / Cabin Heating function
-
Cockpit / Cabin Cooling function.
The Environmental Control System is supplied by ”BUS 2” bar and protected by the ”AIR COND” CB160 circuit
breaker. Four fans are supplied by ”BUS 4” bar and protected respectively by following circuit breakers : ”COND
FAN” CB114, ”CABIN FAN” CB113, ”COCKPIT FAN” CB112 and ”GND FAN” CB111.
The system includes an automatic load shedding feature which :
-
shuts off the Ground Fan (GF) and the Condenser Fan ”COND FAN” and opens compressor clutch when
”MAIN GEN”
CAS message is ON.
-
shuts off all the Vapor Cycle System (VCS) during engine start.
