Air Management System Questions Flashcards by Brendon McNamara

What does the AMS use bleed air for?

ECS (heating & cooling)
Engine start
Pressurization
Engine and wing anti-ice
Water pressure
Hot air leak detection

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How many AMS controllers are installed?

One controller with 2 channels which control the respective onside system

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What happens if a channel fails?

The remaining channel is able to control the entire AMS

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What provides air for the AMS?

Engine bleeds
APU bleed
External Pneumatic Source

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What is bleed air used for?

ECS (heating & cooling)
Engine start
Engine and wing anti-icing
Water pressurization

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What is external pneumatic air used for?

ECS on the ground
Engine start on the ground

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Where is the external ground source panel located?

Lower fairing between the wings

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What is the primary use for APU bleed air?

ECS on the ground
Engine starting on the ground
Electrical source ( < FL330)
Assist with engine start (< FL210)
Bleed source for pressurization, heating, and cooling (< 15,000 ft. MSL)

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Can engine bleed air flow-back to the APU?

No. A check valve prevents flow-back

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Where is bleed air tapped from the engines?

6th and 10th stage compressors (EBV and HSV respectively)
System alternates between valves to regulate an adequate and safe pressure

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What is normal pressure for any engine operation?

45 psi

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What is the purpose of the pre-cooler?

Cools the bleed air coming from the engine to the AMS

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What cools the pre-cooler?

Ground N1 fan
Flight N1 fan or ram air

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What does the Overheat Detection System (ODS) observe?

Engine bleeds and packs
APU bleed
Plumbing for the wing and engine anti-icing system

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Do both loops have to function in order to detect on overheat condition?

Yes, but if one fails the other will work alone to detect the overheat

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How many ECS packs are on the airplane? What provides air for the packs?

2 independent packs (Pack 1 and Pack 2)
Each engine provides bleed air to its respective pack

Can a single pack provide adequate temperature control and pressurization?

Yes, up to FL310

Can a single bleed source power both packs?

Yes, through the crossbleed valve

What is the ratio of fresh air to recirculated air?

52% fresh air to 48% recirculated air

When are the recirculation fans commanded off?

Cockpit switch
Smoke detected in the recirc bay
DUMP button is pressed
Respective pack is commanded off

What keeps the 3 avionic E-BAYs cool?

FWD & CTR E-BAY 3 fans each pull air from cabin to bay
AFT E-BAY Natural air-flow from cabin to bay

When is the Emergency Ram Air Ventilation activated?

Both packs commanded or failed OFF below 25,000 ft. MSL (via left side and electronically controlled)
Ram air pressure greater than cabin pressure (via right side)

How many channels on the Cabin Pressure Control (CPC)?

2 channels, one active and one in standby mode

Where does the CPC get Landing Field Elevation (LFE)?

FMS or can be manually selected

What happens when the dump button is pressed?

* Commands both ECS packs OFF * Opens OFV and raises the cabin to 12,400 ft. at a rate of 2,000 fpm

Can the cabin altitude be raised higher than 12,400 ft.?

* Yes, by using manual mode * Cabin altitude will rise due to natural leak

In manual mode will the cabin depressurize on landing?

* No

What is the bleed system priority in flight?

* Onside engine * Opposite side engine * APU (if available)

If engine and APU bleed air are available simultaneously, which has priority?

* APU has priority if  Aircraft is on the ground  Wheel speed < 50 knots  Opposite engine bleed pressure is not enough for engine start

When will the crossbleed valve automatically open?

* Only one side bleed source is available * Engine 2 start in the air * Engine 1 start in the air if APU is not available

What are some things that will close the ECS packs?

* Any engine start if APU is the bleed source * Engine start on the ground * Respective bleed system duct leak * Bleed air source not available for the pack * TL set to MAX on takeoff * REF A/I set to ALL on takeoff * REF ECS set to OFF on MCDU (APU is OFF)

When are ECS packs recovered?

* TL not at MAX, and  Airplane is 500 AFE with both engines operating  Airplane is > 9,700 MSL with one engine operating

What happens if smoke is detected in the recirculation bay?

* Both recirculation fans deactivate * Cargo recirculation fan deactivates * Cargo outflow valve closes

Where does the CPCS get cruise flight level & landing elevation from?

* FMS before takeoff or CPCS calculates using ambient pressure * LFE may be manually inputted

What color is the LFE on the EICAS?

* Green FMS input * Cyan Manual input (an ‘M’ will be in front of LFE)

What is the ABORT mode?

* Cabin is scheduled back to the takeoff altitude if  Airplane stops climbing and begins a descent, and  Airplane has not climbed > 5,000 AFE or > 10,000 MSL