Air Conditioning

Question 1

The following conditions cause the pack flow control valves to close:

Answer 1

• If an ENG FIRE pb is selected on the overhead FIRE panel
• Selecting the DITCHING pb to “ON” on the overhead CABIN PRESS panel
• Lack of airflow; the valves are spring-loaded to close
• A pack overheat

Question 2

LO PACK FLOW represents a request for _____% of normal flow rate. The pack may automatically select up to _____% air flow if additional cooling is required. HI PACK FLOW represents a request for _____% of normal flow rate.

Answer 2

80%, 100%, 120%

Question 3

HI flow is automatically commanded regardless of position of the PACK FLOW selector when:

Answer 3

• Operating on a single pack
• The APU is providing bleed air

Question 4

Are the ram air inlet flap open or closed on the ground?

Answer 4

During takeoff, the ram air inlet flaps close when takeoff power is set. They open automatically once airborne.

During landing, the ram air inlet flaps close as soon as the main landing gear struts are compressed and will open 20 seconds after the speed drops below 70 knots.

Question 5

When the RAM AIR pb is selected ON, the outflow valve opens about _____%, provided that it is under _____ control and differential pressure is less than _____ PSI.

Answer 5

50%, Automatic, 1.0 PSI

Question 6

The hot air pressure regulating valve will automatically close for the following conditions:

Answer 6

• The absences of hot bleed air (spring loaded)
• Duct overheats when temperatures exceed 88 degrees C
• Cockpit trim air valve failure
• Both cabin trim air valves fail

Question 7

Temperature selection on the condition panel can be made from 18 to 30 degrees C or _____ to _____ degrees F.

Answer 7

64 degrees F, 86 degrees F

Question 8

Cabin zone temperatures set from the flightdeck may be fine tuned from the Temperature Control panel located on the Flight Attendant Panel. Adjustments made from this panel have a limited authority of +/- _____ degrees C or +/- _____ degrees F.

Answer 8

2.5 degrees C, 4.5 degrees F

Question 9

When does the mixing unit change to amber?

Answer 9

The mixing unit changes to amber if air flow from the packs is not provided.

Question 10

To regulate the temperature in the three aircraft zones, the _____ can increase both APU or engine _____ speeds to meet the demands of the air conditioning system.

Answer 10

ACSCs, Idle

Question 11

Can the APU and LP be used simulataneously?

Answer 11

APU Bleed may be used with LP connected, but the packs can not be.

APU Bleed may not be used with HP air.

Question 12

What is the 12 o’clock position for the Cabine Zoner Temperature Selectors?

Answer 12

76 degrees F