Air Management System Flashcards
Air Management Systems consists of what?
- Pneumatics
- Environmental control system
- Pressurization
AMS get air from?
Engines, APU or external air source
Pneumatics uses air for what?
- ECS
- Engine start
- Pressurization
- Anti-Ice (APU bleed not used for A/I)
- Water pressure
What stages does bleed air come from engines?
6th (low) and 10th (high) stages of the compressor
Do both packs need to be turned off when using external air for engine start?
Yes
Where do the packs get air from?
Pack 1, engine 1
Pack 2, engine 2
Bleed logic
Onside, opposite side, APU
Recirc fans purpose?
Reduce load on packs by mixing already conditioned air with incoming cabin/cockpit air (52% fresh to 48% recirculated air)
Emergency RAM air enters the left side of system through a valve if?
Inflight and both packs off/failed and below 25,000’
Positive pressure relief valve (PPRV) opens when?
Cabin pressure reaches 8.6 psi
Dump function
- 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
CABIN ALT HI warning when?
9700’
How many AMS controllers are installed?
1 controller with 2 channels which control the respective onside system
What happens of an AMS controller channel fails?
The remaining channel can control entire AMS
What provides air for AMS?
Engine bleeds, APU bleed, external air source
Can engine bleed flow back to APU?
No, a check valve prevents flow back
What is normal pressure for any engine operation?
45 psi
Purpose of pre-cooler?
Cools bleed air coming from engine to AMS
What does overheat detection system observe?
- Engine bleeds and packs
- APU bleed
- Plumbing for the wing and engine anti-ice
Do both loops have to function in order to detect an overheat condition?
Yes, unless one fails, the other will work alone
How many ECS packs are on the plane?
2,left and right (each engine provides bleed air to 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 a cross bleed valve
When are the recirculation fans commanded off?
- Cockpit switch
- Smoke detected in the recirculation bay
- Dump button is pressed
- Respective pack commanded off
What keeps the 3 avionics E-BAYS cool?
FWD and CTR E-BAY, 3 fans pull cabin air to bay
AFT E-BAY, natural airflow from cabin to bay
If engine and APU bleed air are available simultaneously, which has priority?
APU has priority if
- Aircraft is on ground
- Wheel speed less than 50 knots
- Opposite engine bleed pressure is not enough for engine start
When will the cross bleed valve automatically open?
Only one side bleed source available
Engine 2 start in air
Engine 1 start in the air if APU not available
Negative pressure relief valve opens when?
Opens automatically when outside (ambient) pressure > cabin pressure
Positive pressure relief valve opens?
Opens when cabin pressure reaches 8.6 psi
What are some things that will close the packs?
- 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)
When are ECS packs recovered?
Thrust levers not at MAX, and
- Airplane is 500 AFE with both engines operating
- Airplane is > 9,700 MSL with one engine operating
