Pneumatics

Question 1

How would the bleeds and packs be configured for a summer takeoff in IAH with an APU deferred by MEL?

Answer 1

Engine bleeds “OPEN” and APU bleed “CLOSED” with packs OFF.

Question 2

When will the cross-bleed valve open automatically; when the cross-bleed knob is in the AUTO position?

Answer 2

During a cross-bleed start or anytime that there is demand for bleed air from the other side of the system.

Question 3

Regarding the priority logic of the available bleed sources. If the APU bleed was selected open, what would occur after opening the engine 1 bleed valve?

Answer 3

The APU bleed valve would close.

Question 4

What are the indications of a bleed leak?

Answer 4

A red “LEAK” inscription appears over the button of the affected bleed. Additionally, the EICAS BLD 1(2) LEAK master warning will be presented.

Question 5

While taxing in icing conditions, is it possible for the APU bleed to be used on the ground for the PACKs while simultaneously using engine lip anti-ice protection?

Answer 5

Yes, the engine bleed air used for the engine lip anti-ice protection does not require the engine bleed valve to be open.