air management system

Question 1

what does the air management system consist of?

Answer 1

pneumatic system
environmental control system

Question 2

what does the AMS use bleed air for?

Answer 2

ECS (heating and cooling)
Engine start
pressurization
engine and wing anti-ice
water pressure
hot air leak detection (?)

Question 3

how many AMS controllers are installed?

Answer 3

One controller with 2 channels which control the respective onside system.
in case of channel failure - the remaining channel is able to control the entire pneumatic, air conditioning and anti-ice system

Question 4

what provides bleed air for the AMS?

Answer 4

engine bleeds
APU bleed
External pneumatic source

Question 5

what is external pneumatic air used for?

Answer 5

ECS on the ground
Engine start on the ground

Question 6

Where is the external ground source panel located?

Answer 6

lower fairing between the wings

Question 7

what is the primary use for APU bleed air?

Answer 7

ECS on the ground
Engine starting on the ground
Electrical source (< FL330)
Assist with engine start (< FL 210)
bleed source for pressurization, heating and cooling (<15,000 ft MSL)

Question 8

can engine bleed air flow-back to the APU?

Answer 8

No. a check valve prevents flow-back

Question 9

where is bleed air tapped from the engines?

Answer 9

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

Question 10

what is normal pressure for any engine operation

Answer 10

45 PSI

Question 11

what is the purpose of the pre-cooler

Answer 11

cools the bleed air coming from the engine to the AMS

Question 12

what cools the pre-cooler?

Answer 12

Ground N1 fan
Flight N1 fan or RAM air

Question 13

what does the overheat detection system (ODS) observe?

Answer 13

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

Question 14

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

Answer 14

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

Question 15

how many ECS packs are on the airplane? what provides air for the packs?

Answer 15

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

Question 16

can a single pack provide adequate temperature control and pressurization?

Answer 16

yes up to FL 310

Question 17

can a single bleed source power both packs

Answer 17

yes thru the cross bleed valve

Question 18

what is the ratio of fresh air to recirculated air?

Answer 18

52% fresh to 48% recirculated air

Question 19

when are the recirculation fans commanded off?

Answer 19

cockpit switch
smoke detected in the recirc bay
DUMP button is pressed
respective pack is commanded off

Question 20

what keeps the 3 avionics E-BAY cool?

Answer 20

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

Question 21

When is the Emergency Ram Air Ventilation activated?

Answer 21

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)

Question 22

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

Answer 22

2 channels, one active and one in standby mode

Question 23

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

Answer 23

FMS or can be manually selected

Question 24

what happens when the dump button is pressed?

Answer 24

commands both ECS packs and recirc fans OFF
Opens OFV and raises the cabin to 12,400’ at a rate of 2,000 FPM

Question 25

Can the cabin altitude be raise higher than 12,400'?

Answer 25

yes by using manual mode cabin altitude will rise due to natural leak

Question 26

in manual mode, will the cabin depressurize on landing?

Answer 26

no

Question 27

what is the bleed system priority in flight

Answer 27

onside engine opposite side engine APU (if available)

Question 28

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

Answer 28

APU has priority if aircraft is on the ground wheel speed <50 kts opposite engien bleed pressure if not enough for engine start

Question 29

when will the cross bleed valve automatically open?

Answer 29

only one side bleed source is available engine 2 start in the air engine 1 start in the air if APU is not available

Question 30

what are some things that will close the ECS packs?

Answer 30

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)

Question 31

When are ECS packs recovered?

Answer 31

TL not as MAX, and airplane is 500 AFE with both engines operating Airplane is >9,700 MSL with one engine operating

Question 32

what happens if smoke is detected in the recirculation bay?

Answer 32

both recirc fans deactivate cargo recirc fan deactivates cargo outflow valve closes

Question 33

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

Answer 33

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

Question 34

what color is the LFE on the EICAS?

Answer 34

green FMS input cyan manual input (an M will be in front of LFE)

Question 35

what is the ABORT mode?

Answer 35

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

Question 36

When is the Engine bleed valve (EBV) commanded open?

Answer 36

- respective bleed switch it set to AUTO -respective engine bleed is available - no fire is detected in the respective engine - no bleed duct leak is detected - During single AMS pack operation with both bleed valves available, the engine bleed valve associated to the inoperative pack is commanded to close and the crossbleed valve is commanded to open. The EICAS message BLEED 1 (2) OFF is not displayed in this condition.

Question 37

when is the APU bleed valve commanded open?

Answer 37

APU switch set to AUTO APU bleed available No APU and bleed duct leak left engine bleed is unavailable anti-ice system not requested (or anti-ice system requested ON and anti-ice system is failed)

Question 38

what does the overheat detection system consist of and provide?

Answer 38

overheat sensors and electronic control which provides rapid and reliable overheat and leak detection for the engine bleed, air conditioning ducts, APU bleed air distribution and anti-ice supply ducting

Question 39

what is the purpose of the emergency ram air ventilation and when is it open? (pack 1)

Answer 39

in case of pack shut down or for smoke removal. open only if both ECS cooling packs are commanded OFF or failed OFF and plane altitude is less than 25,000'

Question 40

pack 2 - emergency ram air ventilation has a check valve that is open when?

Answer 40

when the pressure in the ram air circuit is great than the cabin pressure. open during smoke removal

Question 41

what does the cabin pressure control system consist of? what modes does it have?

Answer 41

automatic and manual modes cabin pressure controller (CPC) one cabin outflow valve (OFV) one negative pressure relief valve (NPRV) one positive pressure relief valve (PPRV) static pressure port

Question 42

when does the NPRV open?

Answer 42

when differential pressure between the cabin and surrounding environment exceeds -.5 PSI

Question 43

when does the PPRV open?

Answer 43

when the differential pressure between the cabin and surrounding environment exceeds 8.6 PSI

Question 44

what are the two nominal differential pressures set by the CPCS? what altitudes set what pressures?

Answer 44

37000 and below, the nominal pressure is 7.8PSI 37,000 and above, the nominal pressure is 8.4 PSI