Air Management System

Question 1

What are the three bleed air sources?

Answer 1

Engine 1
Engine 2
APU

Question 2

What is the outflow valve?

Answer 2

Controls airflow from the cabin to the outside ambient air. This controls pressurization. Usually operated automatically, but can be operated manually.

Question 3

What does Ram Air provide for the AMS?

Answer 3

Provides emergency ventilation in case of:
- Pack shutdown
- Smoke removal

Question 4

When are the ram air valves automatically opened?

Answer 4

If both packs are OFF below 25,000 feet.

Question 5

What does the check valve do?

Answer 5

Only allows ram air into the cabin when the ram air pressure is greater than cabin pressure.

Question 6

What is a PACK?

Answer 6

Pneumatic Air Conditioning Kit.

Question 7

How many PACKs onboard and what do they provide?

Answer 7

Two PACKs provide cabin heating, air conditioning, and pressurization. Each PACK is normally supplied bleed air from the same side engine.

Question 8

Can a single engine provide bleed air to both PACKs?

Answer 8

Yes when the crossbleed valve is open.

Question 9

What is the max single PACK altitude?

Answer 9

31,000’

Question 10

What does the safety valve do?

Answer 10

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)

Question 11

What does the safety valve do in relation to negative pressure?

Answer 11

There is a separate negative pressure relief valve that opens if cabin exceeds -0.5 PSI.

Question 12

What can the engines supply bleed air for?

Answer 12

• ECS (Environmental Control System)
• Water pressurization
• Engine Start
• Engine and wing anti-ice

Question 13

What can the APU supply bleed air for?

Answer 13

• ECS (Environmental Control System) (Up to 15,000’)
• Water pressurization
• Engine Start (Up to 21,000’)

Question 14

Which cargo compartment can dry ice or animals be put?

Answer 14

The forward only (though not at the same time). The forward is pressurized and has air circulation, while the aft does not.

Question 15

In the event of a forward cargo fire, what happens in relation to the ECS system?

Answer 15

The compartment is isolated from the main cabin by a shutoff and check valve. The fan is commanded OFF.

Question 16

When is the PACK automatically turned off?

Answer 16

During engine start or an associated bleed system duct leak is detected.

Question 17

What are the two external air connectors?

Answer 17

High Pressure - for engine starting with inoperative APU

Low Pressure - for cabin heating and cooling

Question 18

What happens when you press the pressurization dump button?

Answer 18

• 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

Question 19

What happens if you press the pressurization dump button a second time?

Answer 19

The system returns to normal.

Question 20

When do the passenger O2 masks automatically drop?

Answer 20

If cabin altitude reaches 14,000 to 14,750 feet.

Question 21

How are the passenger O2 masks supplied oxygen and how long does it last?

Answer 21

By an oxygen chemical generator. Approximately 12 minutes.