Term
| Engine Bleed Air FAULT light |
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Definition
Bleed air overheat or overpressure
HP bleed valve or PRV open when commanded closed |
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Term
| Engine Bleed Air switches ON |
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Definition
Engine Bleed Air valve opens for engine start
Engine Bleed Air valve, PRV and HP Bleed valve open by system logic when bleed air pressure is available |
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Term
| With the Engine Bleed Air switch OFF is bleed air available for NAI? Thrust reversers? Any exceptions? |
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Definition
Yes, it is available
Exceptions:
PRV failed closed
PRV closed due to bleed overheat
Start valve not closed
Also, NAI not available if HP Bleed Valve has failed open |
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Term
| Which systems utilize bleed air? |
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Definition
Air conditioning, pressurization
Wing and engine anti-ice, aft cargo heat
Engine start, thrust reversers
Leading edge flaps
Cargo smoke detection
Hydraulic and potable water tank pressurization
Air-driven hydraulic demand pumps |
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Term
| Which valves open with bleed air pressure? |
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Definition
Engine Bleed valves
Nacelle Anti-ice
Packs |
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Term
| When are engine bleed High Pressure and Intermediate Pressure used? |
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Definition
HP: descent and low power settings
LP: high power settings |
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Term
| Describe the general function of the PRV |
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Definition
| Limits bleed air pressure to prevent damage to ducting and equipment |
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Term
| How are the Engine Bleed Air valves opened? |
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Definition
| Pressure actuated, they need engine bleed air to open |
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Term
| Which valves are controlled by the Engine Bleed Air switches? |
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Definition
Engine bleed air valve
PRV
HP bleed valve |
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Term
| What prevents reverse air flow into the engine compressor sections during start? |
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Definition
| The PRV is positively closed |
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Term
| What happens if the Engine Start Valve fails to close? |
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Definition
Bleed air is isolated from the engine starter
The PRV and engine bleed air valve remain closed |
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Term
| Which systems are unavailable if the Engine Start Valve fails to close? |
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Definition
Nacelle anti-ice
Thrust reverse |
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Term
| Which valves close in the engine if a bleed air overheat is detected? |
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Definition
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Term
| What conditions in the engine bleed air system would prevent nacelle anti-ice operation when the bleed air switch is ON? OFF? |
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Definition
ON:
PRV has failed closed
PRV has been closed due to a bleed air overheat
Start valve is not closed
OFF:
All of the above and if the HP Bleed valve is failed open |
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Term
| How would you isolate a bleed air duct section in the event of a bleed duct leak? |
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Definition
Close the respective isolation valve
Close the engine bleed air valves |
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Term
| The center duct provides air supply to which aircraft systems? |
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Definition
Cargo smoke detection
Potable water pressurization
LLCCAFR trim air
Trim air
Aft cargo heat |
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Term
| If the center duct is isolated, how is temperature controlled in all temperature zones? |
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Definition
All temperature zones operate in backup temperature control mode
Trim air is unavailable |
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Term
| Which systems are affected when the left or right duct section is isolated? |
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Definition
Leading edge flaps operate electrically in secondary mode
HYD demand pump 1 or 4 is selected OFF for approach
(prevents HYD PRESS DEMAND msg)
Max of one air conditioning pack
(to assure sufficient thrust from engines) |
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Term
| How do the leading flaps extend when one side has been isolated due to a bleed duct leak? What EICAS msg is displayed? |
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Definition
Revert to secondary mode and extend electrically
FLAPS PRIMARY (until LEF flaps extended) |
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