Air systems

Question 1

DUAL BLEED light Amber means ?

Answer 1

APU bleed air valve open and engine No. 1 bleed air switch on, or engine No. 2 bleed air switch on, APU bleed air valve and isolation valve open.

Question 2

ISOLATION VALVE switch AUTO ?

Answer 2

Closes isolation valve if BOTH engine bleed air switches are ON and BOTH air conditioning PACK switches are AUTO or HIGH.

Opens isolation valve automatically if EITHER engine bleed air or air conditioning PACK switch positioned off

Question 3

BLEED TRIP OFF light Amber ?

Answer 3

Excessive engine bleed air temperature or pressure

related engine bleed air valve closes automatically

Question 4

DUCT OVERHEAT light Amber ?

Answer 4

bleed air temperature in related duct exceeds limit
air mix babes drive full cold
requires reset

Question 5

ZONE TEMP light Amber ?

Answer 5

CONT CAB indicates a duct temp overheat or failure of the flight deck primary and standby temp control.

FWD CAB or AFT CAB indicates duct temp overheat.

on master recall CONT CAB indicates failure of one of the two controllers.

either FWD CAB or AFT CAB failure of the associated zone temp control.

Question 6

PACK light Amber ? (B737-800)

Answer 6

Pack trip off or failure of BOTH primary or standby pack controls. On master recall EITHER.

Question 7

Ram Air Inlet doors operate when ?

Answer 7

Automatically controlled by the Packs.

Provides cooling air for the heat exchangers.