Bleed/Air Con/pressurization

Question 1

Bleed air provides pressurized air for:

Answer 1

Eng start
Air conditioning
Pressurization
Ice protection
Fuel inerting

Question 2

Primary bleed air source

Answer 2

Engines (4th or 8th stage compressor)

Question 3

Approx px of bleed air manifold

Answer 3

45psi

Question 4

If both engine and APU bleed air available, when is the engine automatically selected?

Answer 4

Wing anti-ice active or ON,
Aircraft clean (flaps/slats retracted)
Alt above 16,500ft

Question 5

What kind of leak/overheat protection is there for the system?

Answer 5

2 loops. Both usually need to detect to trigger leak indication, but one will work if another fails.

Question 6

How many air conditioning packs?

Answer 6

2

Question 7

What does the air conditioning provide and to where?

Answer 7

Ventilation/heating/cooling - cockpit, cabin, fwd cargo
Ventilation - aft cargo
Conditioned air - fwd/mid equipment bays

Question 8

The environmental control system is automatically controlled by what?

Answer 8

2 integrated air system controllers (IASC)

Question 9

Pressurization system maintains pressure by

Answer 9

Controlling air exiting cabin through outflow valve (bottom fuselage, fwd of mid equip bay). Auto controlled by the IASC

Question 10

Components of the px system (types of valves)

Answer 10

1 outflow
2 safety
1 negative
4 equalizing (rapid changes)