PNEUMATICS
AIR CONDITIONING
AND PRESSURIZATION
AIRPLANE
OPERATIONS
MANUAL
2-14-10
Page
8
Code
01
REVISION 38
AOM-145/1114
PACK VALVE OPERATIONAL LOGIC
The Pack Valve receives an electrical input to open when the following
conditions occur simultaneously:
− Air Conditioning Pack Button is pressed to open the valve;
− Respective DC Bus is energized;
− Respective engine is not starting;
− No engine is starting using the APU as pneumatic source;
− No failure in the related pack is detected (overpressure,
overtemperature or duct leakage downstream of the Pack Valve);
and
− No discrete ECS (Environmental Control System) OFF signal is
sent from any related FADEC (A or B).
The FADEC`s discrete ECS OFF signals are produced according to
the following conditions:
1 - During Takeoff or Go Around:
ACTIVATION CONDITIONS FOR ECS OFF SIGNALS
PRESSURE ALTITUDE / TAT °C
ENGINE FADEC MODE
ALL ENGINES
OPERATIVE
(takeoff only)
ONEENGINE
INOPERATIVE
(4)
A or
A1/1
ALL T/O-1
Up to 1700 ft above
takeoff altitude and
TAT above -18°C
(-0.4°F)
Lower than
9700 ft (1)
A1 or A3 ALL T/O-1
Up to 1700 ft above
takeoff altitude (2)
Lower than
9700 ft (3)
A1/3 or
A1P
ALL
T/O-1,T/O
or T/O RSV
Up to 1700 ft above
takeoff altitude (2)
Lower than
9700 ft (3)
A1E
ALL
T/O-1, T/O,
E T/O, T/O
RSV or
E T/O RSV
Up to 1700 ft above
takeoff altitude (2)
Lower than
9700 ft (3)
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