Air Management System Flashcards
The Air Management System (AMS) consists of:
- pneumatic system
- environmental control system (ECS)
What does the AMS controller do?
provides primary control for various airplane subsystems such as
- bleed control
- environmental control
- hot air leak detection
- crew oxygen monitoring
- wing ice protection
- engine anti-ice
How many channels does the AMS controller have?
two; control the respective onside system; in case of failure one controller is capable of controlling entire system
PACK (1 or 2) button PUSH IN
allows automatic operation by the AMS; system logic opens pack 1 or 2 flow control valve
PACK (1 or 2) button PUSH OUT
manually closes the pack 1 or 2 flow control valve
RECIRC FAN button PUSH IN
allows automatic operation by the AMS; system logic turns on both recirc fans
RECIRC FAN button PUSH OUT
turns off both recirculation fans
XBLEED button PUSH IN
allows automatic operation by the AMS
XBLEED button PUSH OUT
manually closes the crossbleed
BLEED 1/2 button PUSH IN
allows automatic operation by the AMS;
BLEED 1/2 button PUSH OUT
manually closes engine blead; when a leak is detected, and amber light illuminates on the top half of the button
APU BLEED button PUSH IN
allows automatic operation by the AMS
APU BLEED button PUSH OUT
closes the APU bleed valve; when a leak is detected, an amber light illuminates on the top half of the button
DUMP button
provides rapid cabin depressurization by opening the outflow valve and commanding the packs and the recirculation fan off
Bleed air is used by:
- environmental control system (ECS)
- engine start
- engine and wing anti-ice
- water pressurization
How is bleed source automatically controlled
via opening/closing of the Low Pressure Check Valve and of the High Stage Bleed Valve located in the nacelle
How is engine bleed air temperature regulated
by a precooler which uses the engine fan air modulated by the Fan Air Valve (FAMV)
The Engine Bleed Valve is commanded open when the following conditions occur simultaneously:
- respective bleed switch set to AUTO
- respective engine bleed is available
- no fire is detected in the respective engine
- no bleed duct leak is detected
When does the bleed system automatically shut down
when a leak, overpressure or fail condition is identified
The APU Bleed Valve (ABV) is commanded open when the following conditions occur simultaneously:
- APU switch is set to AUTO
- APU bleed is available
- No APU and left bleed duct leak
- left engine bleed is unavailable
- anti-ice system not requested
The cross bleed is commanded open when the XBLEED button is pushed in (AUTO) and any of the following conditions are met:
- one side provides manifold pressure and there is not a bleed air source on the opposite side
- APU bleed button pushed out for main engine start
- engine #2 start in the air
- APU bleed OFF for engine #1 start in the air
- no bleed leak, unless starting the engine
When will the engine bleed #1 be commanded closed
if the cross bleed fails OPEN and the other bleed source is the #2 engine
Describe the Overheat Detection System
comprised of overheat sensors and electronic controls; six zones of dual loop overheat sensors; both loops must detect overheat or leak unless one has failed
The recirculation fans are commanded off when:
- the DUMP button is pressed
- smoke is detected in the recirc bay
- both packs are commanded OFF
- on ground cabin warm-up mode when the APU is the bleed source
- the cargo bay fire signal activates
How many EBAY fans?
FWD EBAY - three fans, draws air from the cockpit
Center EBAY - three fans, draw air from rear cabin return
AFT EBAY - zero fans, air from pax cabin is directed towards underfloor recirc bay
Explain the emergency ram air ventilation
flight deck pack emergency ram air valve is commanded OPEN only if both ECS cooling packs are commanded or fail OFF and altitude is less than 25,000 ft
The AMS Controller logic provides automatic control of:
engine bleed, APU bleed, ECS packs, anti-ice systems, pressurization and recirculation bay smoke detection
What does the CPCS do
Cabin Pressure Control System controls cabin pressurization
The CPCS system consists of:
- cabin pressure controller (CPC)
- one cabin outflow valve (OFV)
- one negative pressure relief valve (NPRV)
- one positive pressure relief valve (safety valve)
- static pressure port
Describe the Cabin Pressure Controller (CPC)
controls cabin pressure by sending a command to the outflow valve to modulate airflow through the valve to maintain aircraft pressurization; has two fully independent automatic channels that alternate following each flight
The Negative Pressure Relief Valve (NPRV) opens if:
differential pressure between cabin and surrounding environment exceed -0.5 psi
The Positive Pressure Relief Valve opens if:
differential pressure exceeds 8.6 psi
CABIN ALTITUDE HI warning
cabin altitude is equal to or higher than 9,700 ft.
AMS CTRL FAIL caution
both AMS controller channels have failed. AMS controller is not in control
BLEED 1 or 2 FAIL caution
a bleed failure has been detected. bleed is no longer available
BLEED 1 or 2 LEAK caution
an overheat condition has been detected at the associated bleed system or pack
BLEED 1 or 2 OVERPRESS caution
an overpressure condition has been detected at the associated bleed system or pack
BLEED APU LEAK caution
an overheat condition has been detected in the APU bleed or both APU overheat detection system loops have failed
CABIN DIFF PRESS FAIL caution
cabin differential pressure is higher than 8.5 psid or lower than -0.3 psid
CENTER EBAY FAN FAIL caution
center ebay fans have failed
CRG FWD VENT FAIL caution
forward cargo fan has failed ON or if the cargo shutoff valve is failed OPEN associated with smoke detected in the cargo compartment
FWD EBAY FANS FAIL caution
forward ebay fans have failed
PACK 1 or 2 FAIL caution
associated pack is no longer available
PACK 2 LEAK caution
an overheat condition has been detected at the bleed duct
PRESN AUTO FAIL caution
both pressurization controller channels have failed in their automatic mode
PRESN MAN FAIL caution
both pressurization controller channels have failed in their manual mode
RECIRC SMK DET FAIL caution
smoke detector has failed
RECIRC SMOKE caution
smoke has been detected in the recirculation bay
AMS CTRL FAULT advisory
one of the two AMS controller channels has failed
BLEED 1 or 2 OFF advisory
associated bleed is turned off
PACK 1 or 2 OFF advisory
associated pack is off inflight
PRESN AUTO FAULT advisory
loss of automatic mode redundancy, one CPCS controller channel has failed
RAM AIR FAULT advisory
forward emergency ram valve has failed closed
XBLEED FAIL advisory
either bleed isolation valve has failed closed and cross bleed is no longer available, or the bleed isolation valve failed open and engine is the source for the right side bleed (bleed 2)
XBLEED SW OFF advisory
bleed isolation button has been pushed out
