Air Systems

Question 1

Bleed air is supplied to ____.

Answer 1

Aft cargo heat
Air conditioning
Air driven hydraulic pumps
APU and engine start
Equipment cooling
Hydraulic reservoir pressurization
Potable water system pressurization
Pressurization
TAT probe aspiration
Wing and engine anti−ice

Question 2

APUbleed air is used primarily during ____ for ____.

Answer 2

during ground operations, for air conditioning pack operation and engine starting

Question 3

The engine bleed air valves are armed when the ENGINE bleed switches are selected ON. For what reasons do the engine bleed valves close automatically?

Answer 3

During engine start
For bleed source loss
For bleed air over−temperature
For bleed air overpressure
For a bleed air duct leak
When an engine fire switch is pulled
When a ground cart is supplying air

Question 4

Left, center, and right isolation valves divide the bleed air duct into segments. The center isolation valve is normally closed, except during ____.

Answer 4

during engine start or single engine bleed source operation.

Question 5

Engine bleed air comes from____.

Answer 5

High stage or low stage engine compressor section.

Question 6

Whenone pack enters standby cooling mode and the other is operating normally, the pack in standby may automatically shutdown at _____ and will restart when____.

Answer 6

at lower altitudes or higher outside air temperatures when ambient conditions permit standby cooling

Question 7

Air from the lower recirculation fans is mixed with _____ before entering supply ducts. Air from the upper recirculation fans feeds directly into the_____.

Answer 7

pack air supply ducts.

Question 8

The target temperatures of each passenger cabin temperature zone can be modified ____degrees F, within the range of ____F to ____F.

Answer 8

plus or minus 10 degrees; 65; 85

Question 9

The FLIGHT DECK TEMP selector sets flight deck temperature between ____degrees F and ____ degrees F.

Answer 9

65, 85

Question 10

The HIGH setting on the bulk cargo temperature selector turns on bulk ventilation fan, which provides for animal carriage. What does an overheat in the aft or bulk compartment cause? Can heat be restored?

Answer 10

The system to shut down automatically and an EICAS advisory message CARGO HEAT (AFT/BULK). Cargo heat to the affected compartment cannot be restored inflight.

Question 11

The forward cargo compartment is heated by air from the ____.

Answer 11

forward equipment ventilation system.

Question 12

If the forward equipment cooling system is inoperative the EICAS advisory message EQUIP COOLING displays. How is the ground crew made aware of the condition?

Answer 12

The ground crew call horn in the wheel well sounds

Question 13

In flight smoke evacuation of the flight deck and equipment cooling of the lower forward pressurized section is provided by the equipment cooling system override mode. Under what conditions does this override mode operate automatically?

Answer 13

• The EQUIP COOLING switch is OFF, or
• In flight, both supply fans fail, or
• In flight, low airflow is detected, or
• Smoke is detected in the forward equipment cooling system or the forward equipment ventilation system, or
• The FWD CARGO FIRE ARM switch is ARMED.

Question 14

Pack control, fault detection, and overheat protection are automatic. Packs shut down for certain faults, and pressing the AIR COND RESET switch, resets or attempts to reset the pack for which conditions?

Answer 14

• Any closed pack flow shutoff valves or trim air valves closed due to overheat, control failure, or valve failure
• Failed recirculation fan
• Fault protection

Question 15

What protects the cabin against excessive pressure differential.

Answer 15

Two positive pressure relief valves and four negative pressure relief vents