Bleed-Air System

Question 1

Bleed-air is taken from engine compressor
tappings referred to as the ?

Answer 1

The Low Pressure (LP) bleed and High-Pressure (HP) bleed.

Note - LP bleed is used in any flight condition except idling.

Question 2

During idling, which bleed supplies air to the aircraft ?

Answer 2

The HP bleed valve

Question 3

Switching any anti-icing system ON will ?

Answer 3

Activate the temperature modulating function of the HP bleed valve to admit such HP bleedair to the LP bleed flow that the required temperature is maintained.

Question 4

The modulating function is inhibited for …. seconds when ….

Answer 4

60 seconds when TOGA is activated, or continuously while either thrust lever is selected to maximum take-off position.

Question 5

True / false - APU bleed-air is available on the ground only ?

Answer 5

True

Question 6

Overheat switches, when activated, will automatically close ?

Answer 6

The respective HP bleed and
PR/SO valves, and an alert will be presented

Question 7

A Bleed-air leak occuring between the engines and the common
duct will result in the following occurring ?

Answer 7

1. The respective HP bleed, PR/SO, and OP/SO valves will close, and
2. An alert will be presented.

Question 8

What regulates the blled air pressure when the engine pressures become excessive ?

Answer 8

The Pressure Regulating and Shut-Off valve (PR/SO)

Question 9

If a failure of the PR/SO valve causes excessive duct pressure, what controls the downstream bleed pressure ?

Answer 9

The Over Pressure and Shut Off valve (OP/SO)
An alert will also be presented.