Air management system Flashcards
What is the purpose of the Air Management System?
Regulates and distributes air, maintains safe cabin altitude.
What are the components of the Air Management System?
Pneumatics, Environmental Control System (ECS), Pressurization.
What sources provide air for Pneumatics?
Engines, APU, External air source.
What are the uses of Pneumatics?
ECS, Engine Start, Pressurization, Anti-Ice, Water Pressure.
From which stages do engines provide bleed air?
6th (Low) and 10th (High) stages of the compressor.
What is the function of the pre-cooler in the pylon?
Cools incoming air.
What is engine bleed air used for?
ECS, Anti-ice, Water pressure, Pressurization, Engine start.
What is APU bleed used for?
ECS, Water pressure, Pressurization, Engine start.
What is the purpose of the air conditioning cart?
The air conditioning cart can be used to cool the aircraft’s cabin.
What can be used to start an aircraft’s engine?
A High Pressure Air Start cart or air bottle can be used to start an aircraft’s engine.
What must be done to prevent air contamination when starting with an external air source?
Both packs need to be turned OFF when starting with an external air source.
What does the Environmental Control System (ECS) consist of?
The ECS consists of two packs, one located in each wing to fuselage fairing.
Which engine provides air for pack 1?
Engine 1 provides air for pack 1.
Which engine provides air for pack 2?
Engine 2 provides air for pack 2.
How is incoming air temperature controlled?
Incoming air temperature is set via temperature control knobs in the cockpit or by the Flight Attendant.
What is the maximum altitude a single pack can provide air for the entire ECS?
A single pack can provide air for the entire ECS to a maximum altitude of FL310.
What is the function of the recirc fans?
Recirc fans help reduce the load on the packs by recirculating already-conditioned air.
What is the fresh air to recirculated air ratio provided by recirc fans?
Recirc fans provide 52% fresh air to 48% recirculated air.
When will the recirc fans not work?
The fans will not work when the DUMP button is pressed, smoke is detected, or the respective pack is OFF.
What is the purpose of gasper ventilation?
Gasper ventilation provides personal air to each pilot and passenger position.
How is gasper ventilation supplied?
Gasper ventilation is supplied by air from the right recirc fan.
How are the electronic compartments ventilated?
The forward, central, and aft electronic bays are ventilated with conditioned air from the cabin.
How is the forward cargo bay ventilated?
The forward cargo bay receives air from the cabin and is then vented overboard.
How is the aft cargo bay ventilated?
The aft cargo bay is not vented.
What is the purpose of Emergency Ram Air Ventilation?
Allows aircraft ventilation in case of failure of the packs.
When does emergency ram air enter the left side of the system?
In flight, both packs are off/failed, and below 25,000’.
How does emergency ram air enter the right side of the system?
Through a check valve that opens when outside RAM pressure is greater than inside pressure.
What is the function of the Pre-Cooler?
Uses fan and/or ram air to cool the bleed air coming from the engines going to the ECS.
What controls pressurization in the aircraft?
One (1) Cabin Pressurization Control System (CPCS) per aircraft with 2 independent automatic channels.
What components are part of the Cabin Pressurization Control System?
Cabin Pressurization Controller (CPC), Outflow Valve (OFV), Negative Pressure Relief Valve (NPRV), Positive Pressure Relief Valve (Safety Valve), Static Port.
What is the function of the Outflow Valve (OFV)?
Regulates the amount of air leaving the pressure vessel to maintain aircraft pressurization.
What are the two functions of the OFV?
AUTO function - controlled by CPC; MAN function - pilot requests desired position of OFV.
What is the purpose of the LFE in relation to the OFV?
Allows manual input of landing field elevation while still operating in AUTO mode.
When does the Negative Pressure Relief Valve (NPRV) open?
Automatically when outside (ambient) pressure is greater than cabin pressure.
What is the limitation for the NPRV?
-0.5 psi.
When does the Positive Pressure Relief Valve (PPRV) open?
When cabin pressure reaches 8.6 psid (OFV failure) or is mismanaged in manual mode.
What is the function of the Static Port?
Senses and transmits environmental static pressure to the Positive Pressure Relief Valve.
What is the maximum altitude the cabin can climb to in dump function?
12,400 feet at a climb rate of 2,000 feet per minute.
What happens when the dump button is pushed again?
It resets the system.
What does the AMS use bleed air for?
ECS (heating & cooling), engine start, pressurization, engine and wing anti-ice, water pressure, and hot air leak detection.
How many AMS controllers are installed?
One controller with 2 channels controlling the respective onside system.
What happens if a channel of the AMS fails?
The remaining channel is able to control the entire AMS.
What provides air for the AMS?
Engine bleeds, APU bleed, and external pneumatic source.
What is bleed air used for?
ECS (heating & cooling), engine start, engine and wing anti-icing, and water pressurization.
What is external pneumatic air used for?
ECS on the ground and engine start on the ground.
Where is the external ground source panel located?
Lower fairing between the wings.
What is the primary use for APU bleed air?
ECS on the ground and engine starting on the ground.
What is the electrical source limit for APU bleed air?
Below FL330.
What is the assist limit for engine start using APU bleed air?
≤ FL210.
What is the bleed source for pressurization, heating, and cooling with APU bleed air?
≤ 15,000 ft. MSL.
What is the maximum altitude the cabin can climb to in dump function?
12,400 feet at a climb rate of 2,000 feet per minute.
What happens when the dump button is pushed again?
It resets the system.
What does the AMS use bleed air for?
ECS (heating & cooling), engine start, pressurization, engine and wing anti-ice, water pressure, and hot air leak detection.
How many AMS controllers are installed?
One controller with 2 channels controlling the respective onside system.
What happens if a channel of the AMS fails?
The remaining channel is able to control the entire AMS.
What provides air for the AMS?
Engine bleeds, APU bleed, and external pneumatic source.
What is bleed air used for?
ECS (heating & cooling), engine start, engine and wing anti-icing, and water pressurization.
What is external pneumatic air used for?
ECS on the ground and engine start on the ground.
Where is the external ground source panel located?
Lower fairing between the wings.
What is the primary use for APU bleed air?
ECS on the ground and engine starting on the ground.
What is the electrical source limit for APU bleed air?
Below FL330.
What is the assist limit for engine start using APU bleed air?
≤ FL210.
What is the bleed source for pressurization, heating, and cooling with APU bleed air?
≤ 15,000 ft. MSL.
Can engine bleed air flow-back to the APU?
No. A check valve prevents flow-back.
Where is bleed air tapped from the engines?
6th and 10th stage compressors (EBV and HSV respectively).
What is normal pressure for any engine operation?
45 psi.
What is the purpose of the pre-cooler?
Cools the bleed air coming from the engine to the AMS.
What cools the pre-cooler?
Ground N1 fan and Flight N1 fan or ram air.
What does the Overheat Detection System (ODS) observe?
Engine bleeds, packs, APU bleed, and plumbing for the wing and engine anti-icing system.
Do both loops have to function in order to detect an overheat condition?
Yes, but if one fails, the other will work alone to detect the overheat.
How many ECS packs are on the airplane?
2 independent packs (Pack 1 and Pack 2).
What provides air for the ECS packs?
Each engine provides bleed air to its 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 the crossbleed valve.
What is the ratio of fresh air to recirculated air?
52% fresh air to 48% recirculated air.
When are the recirculation fans commanded off?
Cockpit switch, smoke detected in the recirc bay, DUMP button is pressed, respective pack is commanded off.
What keeps the 3 avionic E-BAYs cool?
FWD & CTRE-BAY S fans each pull air from cabin to bay; AFT E-BAY uses natural airflow from cabin to bay.
When is the Emergency Ram Air Ventilation activated?
Both packs commanded or failed OFF below 25,000 ft. MSL or ram air pressure greater than cabin pressure at any altitude.
How many channels on the Cabin Pressure Control (CPC)?
2 channels, one active and one in standby mode
Where does the CPC get Landing Field Elevation (LFE)?
FMS or can be manually selected
What happens when the dump button is pressed?
Commands both ECS packs OFF.
Opens OFV and raises the cabin to 12,400 ft. at a rate of 2,000 fpm.
Shuts off both recirculating fans.
Can the cabin altitude be raised higher than 12,400 ft.?
Yes, by using manual mode.
Cabin altitude will rise due to natural leak.
In manual mode will the cabin depressurize on landing?
No
What is the bleed system priority in flight?
Onside engine, Opposite side engine, APU (if available)
If engine and APU bleed air are available simultaneously, which has priority?
APU has priority if:
- Aircraft is on the ground
- Wheel speed < 50 knots
- Opposite engine bleed pressure is not enough for engine start
When will the crossbleed valve automatically open?
Only one side bleed source is available.
Engine 2 start in the air.
Engine 1 start in the air if APU is not available.
What are some things that will close the ECS packs?
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 All set to ALL on takeoff.
REF ECS set to OFF on MCDU (APU is OFF).
When are ECS packs recovered?
TL not at MAX, and:
- Airplane is 500 AFE with both engines operating.
- Airplane is > 9,700 MSL with one engine operating.
What happens if smoke is detected in the recirculation bay?
Both recirculation fans deactivate.
Cargo recirculation fan deactivates.
Cargo outflow valve closes.
Where does the CPCS get cruise flight level & landing elevation from?
FMS before takeoff or CPCS calculates using ambient pressure.
LFE may be manually inputted.
What color is the LFE on the EICAS?
Green for FMS input.
Cyan for Manual input (an ‘M’ will be in front of LFE).
What is the ABORT mode?
Cabin is scheduled back to the takeoff altitude if:
- Airplane stops climbing and begins a descent,
- Airplane has not climbed > 5,000 AFE or > 10,000 MSL.
