Air Management System

Question 1

Air Management Systems consists of what?

Answer 1

• Pneumatics
• Environmental control system
• Pressurization

Question 2

AMS get air from?

Answer 2

Engines, APU or external air source

Question 3

Pneumatics uses air for what?

Answer 3

• ECS
• Engine start
• Pressurization
• Anti-Ice (APU bleed not used for A/I)
• Water pressure

Question 4

What stages does bleed air come from engines?

Answer 4

6th (low) and 10th (high) stages of the compressor

Question 5

Do both packs need to be turned off when using external air for engine start?

Answer 5

Yes

Question 6

Where do the packs get air from?

Answer 6

Pack 1, engine 1

Pack 2, engine 2

Question 7

Bleed logic

Answer 7

Onside, opposite side, APU

Question 8

Recirc fans purpose?

Answer 8

Reduce load on packs by mixing already conditioned air with incoming cabin/cockpit air (52% fresh to 48% recirculated air)

Question 9

Emergency RAM air enters the left side of system through a valve if?

Answer 9

Inflight and both packs off/failed and below 25,000’

Question 10

Positive pressure relief valve (PPRV) opens when?

Answer 10

Cabin pressure reaches 8.6 psi

Question 11

Dump function

Answer 11

• Only works in auto mode
• Shuts OFF packs and recirculation fans
• Allows cabin to climb to max altitude of 12,400 feet @ 2000 fpm climb rate

Question 12

CABIN ALT HI warning when?

Answer 12

9700’

Question 13

How many AMS controllers are installed?

Answer 13

1 controller with 2 channels which control the respective onside system

Question 14

What happens of an AMS controller channel fails?

Answer 14

The remaining channel can control entire AMS

Question 15

What provides air for AMS?

Answer 15

Engine bleeds, APU bleed, external air source

Question 16

Can engine bleed flow back to APU?

Answer 16

No, a check valve prevents flow back

Question 17

What is normal pressure for any engine operation?

Answer 17

45 psi

Question 18

Purpose of pre-cooler?

Answer 18

Cools bleed air coming from engine to AMS

Question 19

What does overheat detection system observe?

Answer 19

• Engine bleeds and packs
• APU bleed
• Plumbing for the wing and engine anti-ice

Question 20

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

Answer 20

Yes, unless one fails, the other will work alone

Question 21

How many ECS packs are on the plane?

Answer 21

2,left and right (each engine provides bleed air to respective pack)

Question 22

Can a single pack provide adequate temperature control and pressurization?

Answer 22

Yes, up to FL310

Question 23

Can a single bleed source power both packs?

Answer 23

Yes, through a cross bleed valve

Question 24

When are the recirculation fans commanded off?

Answer 24

• Cockpit switch
• Smoke detected in the recirculation bay
• Dump button is pressed
• Respective pack commanded off

Question 25

What keeps the 3 avionics E-BAYS cool?

Answer 25

FWD and CTR E-BAY, 3 fans pull cabin air to bay AFT E-BAY, natural airflow from cabin to bay

Question 26

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

Answer 26

APU has priority if - Aircraft is on ground - Wheel speed less than 50 knots - Opposite engine bleed pressure is not enough for engine start

Question 27

When will the cross bleed valve automatically open?

Answer 27

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

Question 28

Negative pressure relief valve opens when?

Answer 28

Opens automatically when outside (ambient) pressure > cabin pressure

Question 29

Positive pressure relief valve opens?

Answer 29

Opens when cabin pressure reaches 8.6 psi

Question 30

What are some things that will close the packs?

Answer 30

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

Question 31

When are ECS packs recovered?

Answer 31

Thrust levers not at MAX, and - Airplane is 500 AFE with both engines operating - Airplane is > 9,700 MSL with one engine operating