Air Systems Flashcards
Bleed air can be supplied by what sources?
Engines, APU, Ground Pneumatics .
How are the Engine Bleed Air Valves actuated?
Pressure actuated, remain closed until there is sufficient pressure to cause forward flow.
How is the APU Bleed Air Valve actuated?
Automatic Electric Control, electrically actuated
What is the meaning of a momentary VALVE light on the Pneumatic Panel?
Valve is in transit.
What is the meaning of an illuminated Isolation “VALVE” light?
The valve disagrees with the commanded position.
Describe the function of the ON (flow bar in view) position of the Engine Bleed Air switch.
The engine bleed air valve opens when engine bleed air is available. Valve may close during engine start with APU, Ground Pneumatics air connected or during periods of low engine bleed air demand (packs off).
What is the meaning of an illuminated Engine Bleed Air “OFF” light?
Engine Bleed Air Valve is closed.
System fault, switch is OFF, engine is not running or bleed air pressure has not been sufficient to open the valve
Describe the function of the “OFF” position of the Engine Bleed Air Switch.
Valve is manually closed.
What is the meaning of an illuminated “HI STAGE” light?
The engine bleed system pressure is excessive, the engine high pressure bleed air valve is automatically locked closed.
What is the meaning of the “BLEED” and Engine Bleed “OFF” lights illuminating simultaneously?
Engine bleed air temperature is excessive and the engine bleed valve has closed.
What is the meaning of an illuminated “DUCT LEAK” light? Does anything happen automatically?
A high temperature bleed air leak is detected. Nothing happens automatically because the isolation valve is normally closed.
What is the function of the “STBY - N” position of the Pack Control Selector?
Normal - Regulates pack outlet temperature to a constant, moderate temperature.
What is the function of the “STBY - W” position of the Pack Control Selector?
Warm - Full warm pack operation.
What is the meaning of an illuminated “PACK OFF” light?
The Pack Valve is closed.
What is the meaning of an illuminated pack “INOP” light?
The Pack is overheated.
Fault in the automatic control system.
What is the meaning of an illuminated Pack “INOP” and “PACK OFF” light?
There has been an internal pack overheat and the pack has shut down automatically.