Air Management System

Question 1

Can a single pack provide adequate temperature control and pressurization?

Answer 1

Yes

(up to FL310)

Question 2

What is the normal pressure for any engine operation?

Answer 2

45 psi

Question 3

What is the primary use for APU bleed air?

Answer 3

• APU bleed air
• ECS on the ground
• Engine start on the ground
• Electrical source (< FL330)
• Assist with engine start (< FL210)
• Bleed source for pressurization and packs (< 15,000 ft)

Question 4

Where does the CPC get landing field elevation?

Answer 4

FMS

( can be manually selected )

Question 5

What happens when the Dump Button is depressed?

Answer 5

Opens the OutFlow Valve

Commands the Packs and Recirc Fans off

A White Bar illuminates on the button

Question 6

What keeps the 3 avionics E-bays cool?

Answer 6

FWD and CTR:

• 3 fans each pull from cabin to bay

AFT:

• Natural air flow from cabin to bay

Question 8

Can a single bleed source power both packs?

Answer 8

Yes

( through the crossbleed valve )

Question 9

In manual mode will the cabin depressurize on landing?

Answer 9

No

Question 10

What are some conditions that will close the ECS packs?

Answer 10

• Any engine start if APU is the bleed source
• Engine start on the ground
• Respective bleed system duct leak
• Bleed source not available for the pack
• Thrust lever set to max on T/O
• REF ECS set to off on MCDU (APU is off)

Question 11

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

Answer 11

• FMS before takeoff or CPCS calculates using ambient pressure
• LFE may be manually input

Question 12

What does the overheat detection system (ODS) observe?

Answer 12

Overhead and Leak Detection for:

Engine Bleeds

AC Ducts

APU Bleed Air Distribution

Anti-Ice Supply Ducting

Question 13

When will the crossbleed valve automatically open?

Answer 13

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

Question 14

Where is the bleed air tapped from the engines?

Answer 14

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

Question 15

What is the ABORT mode?

Answer 15

Cabin is scheduled back to the takeoff altitude if:

• Airplane stops climbing and begins a descent

AND

• Airplane has not climbed > 5000 AFE or > 10000 MSL

Question 16

What provides air for the AMS?

Answer 16

• Engine bleeds
• APU bleed
• External pneumatic source

Question 17

When are ECS packs recovered?

Question 18

Can engine bleed air flow back to the APU?

Answer 18

No

(check valve prevents flowback)

Question 19

How many AMS controllers are there?

Answer 19

One controller with 2 channels which

control their respective onside system

Question 20

What color is the LFE on the EICAS?

Answer 20

• Green FMS input
• Cyan manual input (an “M” will be in front of LFE)

Question 21

How many channels on the cabin pressure control (CPC)?

Answer 21

2

( one active and one in standby mode )

Question 22

What happens when the dump button is pressed?

Answer 22

• Commands both ECS packs off
• Opens OFV and raises cabin to 12400ft at 2000fpm

Question 23

When are the recirc fans commanded off?

Answer 23

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

Question 24

What is the bleed system priority in flight?

Answer 24

• Onside engine
• Offside engine
• APU

Question 25

How many ECS packs are on the airplane?

What provides air for the packs?

Answer 25

2 independent packs left and right

(each engine provides bleed air to its respective pack)

Question 26

When is the emergency ram air ventilation activated?

Answer 26

• Both packs commanded off or failed < FL250 (left side electronically controlled)
• Ram Air pressure greater than cabin pressure (right side)

Question 27

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

Answer 27

No. Though Dual Loop is Normal. But if a single loop fails the remaining monitors the system

Question 28

What is the ratio of fresh air to recycled air?

Answer 28

52% fresh

48% recycled

Question 29

What happens if smoke is detected in the recirculation bay?

Question 30

What is bleed air used for?

Answer 30

• ECS heating and cooling
• Engine start
• Engine and wing A/I
• Water pressurization

Question 31

Where is the external ground source panel located?

Answer 31

Lower fairing between the wings

Question 32

What cools the pre-cooler?

Question 33

What is the AMS used for?

Answer 33

• ECS ( Heating and Cooling)
• Engine start
• Pressurization
• Engine and wing A/I
• Water pressure
• Hot air leak detection

Question 34

Can the altitude be raised higher than 12400ft?

Answer 34

Yes

( Using manual mode, cabin altitude will rise due to a natural leak )

Question 35

What is the purpose of the precooler?

Answer 35

Cools the bleed air supplied to the AMS

Question 36

Which bleed source, Engine or APU, has priority?

Answer 36

The APU has priority IF:

• Aircraft is on ground
• Wheel speed <50 kts

( Offside engine bleed psiis not enough for engine start)

Question 37

What happens if a channel fails?

Answer 37

The remaining channel is able to control the entire AMS