Air Systems

Question 1

What is the air source for the packs?

Answer 1

Outside air

Question 2

How many Cabin Air Compressors (CACs) are there?

Answer 2

Four

Question 3

What is the purpose of the CACs?

Answer 3

Pressurize and regulate the flow of outside air to the packs.

Question 4

How many CACs are required to provide sufficient air to a single pack in all modes?

Answer 4

One

Question 5

How many pack control systems are there?

Answer 5

Two

Question 6

Following a pack shut down, how can the pack be reset?

Answer 6

Pressing the AIR CONDITIONING RESET switch

Question 7

In Standby Cooling mode, which messages are displayed on:

a. EICAS?

Answer 7

a. PACK MODE (L/R) – EICAS Advisory

Question 8

In Standby Cooling mode, which messages are displayed on:

b. Air synoptic?

Answer 8

b. STBY COOLING (amber)

Question 9

What is the source of flight deck air?

Answer 9

The flight deck receives 100% conditioned outside air

Question 10

When would recirculated air be supplied to the flight deck?

Answer 10

When one pack is off and it’s associated lower recirculation fan is on.

Question 11

What is the purpose of the Recirculation Fans?

Answer 11

They assist the packs to maintain a constant ventilation rate through the cabin

Question 12

What is the result of switching the Recirculation Fans to OFF?

Answer 12

Decreased air flow in the cabin

Question 13

What is the purpose of the Alternate Ventilation System (AVS)?

Answer 13

To ventilate the cabin and flight deck when both packs are inoperative

Question 14

Where is the selected Cabin Master temperature indicated?

Answer 14

The AIR synoptic

Question 15

What is the source of trim air?

Answer 15

From each pack

Question 16

Are all zones supplied with trim air?

Answer 16

Yes

Question 17

What determines the pack outlet temperature?

Answer 17

The temperature zone requiring the coolest temperature

Question 18

Over what temperature range can cabin crew adjust the cabin zones target temperature?

Answer 18

Plus or minus 3 degrees C, within the range of 18 to 29C.

Question 19

What temperature is maintained in all zones if a trim air supply is lost?

Answer 19

The cabin temperature controllers attempt to maintain all zones at the average target temperature

Question 20

What happens if either the flight deck or cabin temperature selection is unavailable to the pack temperature controller?

Answer 20

The pack outlet temperature is regulated to achieve either the last temperature set or an average cabin temperature of 24 C

Question 21

What type of heater is used for:

a. Shoulder heaters?

Answer 21

a. Electric elements in the side window air diffusers

Question 22

What type of heater is used for:

b. Footheaters?

Answer 22

b. Electric heating elements

Question 23

Is shoulder and foot heat available on the ground?

Answer 23

No

Question 24

Where are the controls for the Forward Cargo and Bulk heat?

Answer 24

Overhead panel

Question 25

What is the source of air for the Forward Cargo heating system?

Answer 25

Forward E/E exhaust ventilation air

Question 26

How is the temperature controlled in the Forward Cargo?

Answer 26

Automatically using forward E/E exhaust air, a dedicated refrigeration unit, an in-line electric heater and a forward cargo exhaust fan

Question 27

What does selecting the FWD Cargo Flow switch to HIGH attempt to achieve?

Answer 27

To prevent or remove cargo odors from the passenger cabin

Question 28

What is the source of air for the Bulk Cargo heating?

Answer 28

Cabin air passing through a supply fan, an in-line electric heater and residual heat from the aft E/E cooling exhaust

Question 29

With AUTO selected for the Bulk Cargo temperature, how is airflow increased?

Answer 29

The bulk ventilation fan operates

Question 30

Should live animals be carried in the Aft Cargo compartment? If not, why not?

Answer 30

No, the aft compartment is not temperature controlled

Question 31

What is the source of air for the Aft Cargo heat?

Answer 31

Aft E/E cooling exhaust air

Question 32

Which areas does the Forward Equipment Cooling system provide cooling airflow?

Answer 32

Flight deck and forward E/E equipment compartment

Question 33

Which areas does the Aft Equipment Cooling system provide cooling airflow?

Answer 33

The Aft E/E equipment compartment

Question 34

With the Forward or Aft Equipment cooling system in AUTO: | a. Where is the cooling air drawn from?

Answer 34

a. Cabin air

Question 35

With the Forward or Aft Equipment cooling system in AUTO: | b. What moves the cooling air through the system?

Answer 35

b. One of two supply fans

Question 36

With the Forward or Aft Equipment cooling system in AUTO: | c. Where is the air exhausted?

Answer 36

c. A dedicated overboard vent valve or to the appropriate cargo compartment, if it requires additional heat

Question 37

With the Forward or Aft Equipment cooling system in OVRD: - | a. How is air drawn through the system?

Answer 37

a. Cabin differential pressure draws air to create a reverse flow of air across the equipment

Question 38

With the Forward or Aft Equipment cooling system in OVRD: - | b. Where is this air exhausted?

Answer 38

b. Through the override valve to an overboard venturi

Question 39

What is achieved with the: | a. Forward Equipment Cooling switch in OVRD?

Answer 39

a. Aids smoke evacuation from the flight deck

Question 40

What is achieved with the: | b. Aft Equipment Cooling switch in OVRD?

Answer 40

b. Aids smoke evacuation from the passenger cabin

Question 41

Where is the Power Electronics Cooling System (PECS) located?

Answer 41

Aft E/E equipment compartment

Question 42

What does PECS supply liquid cooling for?

Answer 42

The Large Motor Power distribution system and the supplemental cooling units & associated motor controllers of the Integrated Cooling System (ICS)

Question 43

What colours are used for Cabin Differential Pressure (∆P) operating ranges displayed on EICAS and what do they indicate?

Answer 43

- White: normal operating range - Amber: above normal range - Red: excessive differential pressure

Question 44

What is the indication on the EICAS display that an outflow valve is under manual control?

Answer 44

The letter M (amber) is displayed next to the Outflow Valve Position indicators

Question 45

How many outflow valves are there?

Answer 45

Two, one forward and one aft

Question 46

What protects the fuselage against excessive pressure differentials?

Answer 46

Positive and negative pressure relief valves

Question 47

When in the automatic pressurisation mode, list the data inputs used to calculate pressurisation schedule?

Answer 47

Ambient pressure and flight plan data from the FMC

Question 48

In climb mode, at what rate will the cabin climb?

Answer 48

On a schedule related to the aircraft climb rate and flight plan cruise altitude

Question 49

In cruise mode, what is the maximum cabin altitude?

Answer 49

6,000ft

Question 50

From where is the landing altitude barometric pressure correction obtained?

Answer 50

Captain’s altimeter setting

Question 51

What will the cabin altitude be just before touchdown?

Answer 51

Cabin altitude decrease to slightly below FMC planned landing altitude

Question 52

What happens to the outflow valves at touchdown?

Answer 52

Both valves open to depressurise the cabin

Question 53

How is cabin altitude controlled for: | a. Takeoffs from airports above 8000ft?

Answer 53

a. The cabin descends to the target altitude during climb

Question 54

How is cabin altitude controlled for: | b. Landings at airports above 8000ft?

Answer 54

b. The cabin climbs to 6,000ft and before arrival climbs to destination elevation

Question 55

If a depressurisation occurs, what will the outflow valves do initially?

Answer 55

They close to preserve cabin pressure

Question 56

During a descent after a depressurisation, when will the outflow valves automatically drive to fully open?

Answer 56

When the airplane reaches 15,000ft or descends below the cabin altitude

Question 57

How long does it take for an outflow valve to travel from fully closed to fully open when controlled manually?

Answer 57

30 seconds

Question 58

What supplies bleed air?

Answer 58

The engines.

Question 59

What is bleed air used for?

Answer 59

Engine core and inlet cowl anti–ice operations.