Air Management System Flashcards
What are the three bleed air sources?
Engine 1
Engine 2
APU
What is the outflow valve?
Controls airflow from the cabin to the outside ambient air. This controls pressurization. Usually operated automatically, but can be operated manually.
What does Ram Air provide for the AMS?
Provides emergency ventilation in case of:
- Pack shutdown
- Smoke removal
When are the ram air valves automatically opened?
If both packs are OFF below 25,000 feet.
What does the check valve do?
Only allows ram air into the cabin when the ram air pressure is greater than cabin pressure.
What is a PACK?
Pneumatic Air Conditioning Kit.
How many PACKs onboard and what do they provide?
Two PACKs provide cabin heating, air conditioning, and pressurization. Each PACK is normally supplied bleed air from the same side engine.
Can a single engine provide bleed air to both PACKs?
Yes when the crossbleed valve is open.
What is the max single PACK altitude?
31,000’
What does the safety valve do?
It is a positive pressure relief valve.
- Protects the airplanes structure from damage due to positive overpressure.
- Automatically opens if cabin differential pressure exceeds 8.6 PSI.
- Spring loaded/mechanical (no power required)
What does the safety valve do in relation to negative pressure?
There is a separate negative pressure relief valve that opens if cabin exceeds -0.5 PSI.
What can the engines supply bleed air for?
- ECS (Environmental Control System)
- Water pressurization
- Engine Start
- Engine and wing anti-ice
What can the APU supply bleed air for?
- ECS (Environmental Control System) (Up to 15,000’)
- Water pressurization
- Engine Start (Up to 21,000’)
Which cargo compartment can dry ice or animals be put?
The forward only (though not at the same time). The forward is pressurized and has air circulation, while the aft does not.
In the event of a forward cargo fire, what happens in relation to the ECS system?
The compartment is isolated from the main cabin by a shutoff and check valve. The fan is commanded OFF.
When is the PACK automatically turned off?
During engine start or an associated bleed system duct leak is detected.
What are the two external air connectors?
High Pressure - for engine starting with inoperative APU
Low Pressure - for cabin heating and cooling
What happens when you press the pressurization dump button?
- Opens the outflow valve to command a 2,000 FPM climb to 12,400’ cabin altitude. At 12,400’ the OFV closes.
- Commands PACKs OFF
- Commands recirc fans OFF
What happens if you press the pressurization dump button a second time?
The system returns to normal.
When do the passenger O2 masks automatically drop?
If cabin altitude reaches 14,000 to 14,750 feet.
How are the passenger O2 masks supplied oxygen and how long does it last?
By an oxygen chemical generator. Approximately 12 minutes.
