Air Systems

Question 1

How many packs are on the aircraft?

Answer 1

3

Question 2

What is the function of the packs?

Answer 2

Deliver conditioned bleed air at controlled temps the aircraft.

Question 3

What are the 7 temperature zones?

Answer 3

• Flight Deck
• Crew Rest
• Upper Deck
• FWD Main Cargo
• AFT Main Cargo
• FWD Lower Lobe
• AFT Lower Lobe

Question 4

How many packs can the APU power on the ground?

How many packs can the APU power in the air?

Answer 4

3x Packs on the ground

1x Pack in the air <= 15,000’

Question 5

What is the flight deck temperature range with the Flight Deck (FLT)
temperature Selector in AUTO?

Answer 5

65F to 85F (18C to 29C)

Question 6

What valve are you controlling when you select MAN with the flight deck
temperature controller?

Answer 6

Flight deck trim air valve

Question 7

What does the Zone System (SYS) Fault Light indicate?

Answer 7

• Temperature zone duct overheat or zone temperature controller fault has
occurred.
• Master trim air valve failed closed
• Trim air switch off
• Master trim air valve closed and pack air continues to flow.

Question 8

What is the temperature range with the main deck and forward and aft lobe
temperature selectors in AUTO?

Answer 8

40F to 85F (4C to 29C)

Question 9

Under what conditions would trim air be unavailable to the flight deck, upper
deck, crew rest, and main deck?

Answer 9

• EICAS advisory TEMP ZONE is displayed.
• Center section of the bleed duct is isolated.
• EICAS Advisory message TRIM AIR OFF is displayed.
• The Master Trim Air switch is OFF.

Question 10

If trim air is not available to the flight deck, upper deck, crew rest, and main
deck distribution system, how is temperature controlled in the cabin?

Answer 10

• Backup modes control temperature
• If the flight deck temp selector setting is available to the PTC, pack outlet
temperature of all packs is regulated to an average temp between 65F
and 85F, as set by the Flt Deck Temp selector, or
• If unavailable to the PTC, the last temperature set, or
• If last temp unavailable to the PTC, then 75F (24C)

Question 11

What target temperature is set to the upper deck and crew rest zone when
electrical power is initially applied to the airplane?

Answer 11

75F (24C)

Question 12

How many pack temperature controllers (PTC) are provided?

Answer 12

Two – A and B

Question 13

How many separate channels are provided in the PTCs?

Answer 13

Each PTC has three separate channels, one for each pack.

Question 14

What happens if a pack temperature controller (PTC) detects a fault in a pack
channel?

Answer 14

Control of the respective pack switches to the other PTC.

Question 15

How can you restore pack operation for a failed PTC?

Answer 15

Push the Pack Reset Switch.

Question 16

What would happen if a fault or an overheat of the PTC is detected?

Answer 16

The respective pack valve closes, resulting in a pack shutdown.

Question 17

Equipment cooling provides cooling air for what compartment/systems?

Answer 17

• Flight deck equipment

* Electrical and equipment racks (E & E)

Question 18

When is warm exhaust air ducted overboard through the ground exhaust valve?

Answer 18

• Engines not operating
• Equipment cooling selector in NORM
• Ambient temperature moderate or high

Question 19

When does the equipment cooling system configure for flight?

Answer 19

One or more engines on each wing is operating.

Question 20

How can you manually configure the equipment cooling system for flight?

Answer 20

Positioning the Equipment Cooling Selector to STBY.

Question 21

Which valve is closed when equipment cooling is in closed loop mode?

Answer 21

Inboard exhaust valve

Question 22

What is the source of equipment cooling air for the flight deck electrical equipment?

Answer 22

With two or three packs operating, the flight deck equipment cooling
source valve directs conditioned air into the flight deck electrical
equipment.

Question 23

Describe the operation of the equipment cooling system with the Equipment
Cooling Selector in OVRD.

Answer 23

• Provides equipment cooling in flight if internal fans are inoperative.
• Internal fans are not powered.
• Smoke/override valve opens.
• All other valves closed, no air flow to forward cargo.
• Cabin differential pressure draws air from the panels area on the flight
deck, through the equipment cooling ducts to the E&E, to create a
reverse flow of air across the equipment, then through the supply duct,
then overboard.

Question 24

Under what conditions would the equipment cooling system revert to closed
loop mode?

Answer 24

• LLCCAFR Selector in FWD LOW, BOTH LOW, FWD HIGH, with a
forward lobe temp selector set lower than 10C (50F).
• If a single internal fan fails.
• When the MAIN CARGO FIRE ARM switch is pushed.