02. Air Conditioning

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?
b. Air synoptic?

Answer 7

a. PACK MODE (L/R) – EICAS Advisory b. STBY COOLING (amber)

Question 8

What is the source of flight deck air?

Answer 8

The flight deck receives 100% conditioned outside air

Question 9

Why is the conditioned air in the flight deck maintained at a higher pressure than the cabin?

Answer 9

To prevent smoke from entering the flight deck

Question 10

What is the purpose of the Recirculation Fans?

Answer 10

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

Question 11

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

Answer 11

Decreased air flow in the cabin

Question 12

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

Answer 12

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

Question 13

Where is the selected Cabin Master temperature indicated?

Answer 13

The AIR synoptic

Question 14

What is the source of trim air?

Answer 14

From each pack

Question 15

Are all zones supplied with trim air?

Answer 15

Yes

Question 16

What determines the pack outlet temperature?

Answer 16

The temperature zone requiring the coolest temperature

Question 17

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

Answer 17

Plus or minus 6o C, within the range of 18o to 29o C.

Question 18

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

Answer 18

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

Question 19

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

Answer 19

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

Question 20

What type of heater is used for: -

a. Shoulder heaters? b. Footheaters?

Answer 20

a. Electric elements in the side window air diffusers

b. Electric heating elements

Question 21

Is shoulder and foot heat available on the ground?

Answer 21

No

Question 22

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

Answer 22

Overhead panel

Question 23

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

Answer 23

Forward E/E exhaust ventilation air

Question 24

How is the temperature controlled in the Forward Cargo?

Answer 24

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


Question 25

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

Answer 25

To prevent or remove cargo odors from the passenger cabin

Question 26

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

Answer 26

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

Question 27

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

Answer 27

The bulk ventilation fan operates | 

Question 28

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

Answer 28

No, the aft compartment is not temperature controlled 2.AIR 

Question 29

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

Answer 29

Aft E/E cooling exhaust air

Question 30

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

Answer 30

Flight deck and forward E/E equipment compartment

Question 31

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

Answer 31

The Aft E/E equipment compartment

Question 32

With the Forward or Aft Equipment cooling system in AUTO: - | Where is the cooling air drawn from? Whatmovesthecoolingairthroughthesystem? Where is the air exhausted?

Answer 32

a. Cabin air b. One of two supply fans c. A dedicated overboard vent valve or to the appropriate cargo compartment, if it requires additional heat

Question 33

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

Answer 33

a. Cabin differential pressure draws air to create a reverse flow of air across the equipment b. Through the override valve to an overboard venturi

Question 34

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

Answer 34

a. Aids smoke evacuation from the flight deck | b. Aids smoke evacuation from the passenger cabin

Question 35

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

Answer 35

Aft E/E equipment compartment

Question 36

What does PECS supply liquid cooling for?

Answer 36

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

Question 37

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

Answer 37

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

Question 38

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

Answer 38

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

Question 39

How many outflow valves are there?

Answer 39

Two, one forward and one aft

Question 40

What protects the fuselage against excessive pressure differentials?

Answer 40

Positive and negative pressure relief valves

Question 41

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

Answer 41

Ambient pressure and flight plan data from the FMC

Question 42

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

Answer 42

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

Question 43

In cruise mode, what is the maximum cabin altitude?

Answer 43

6,000ft

Question 44

From where is the landing altitude barometric pressure correction obtained?

Answer 44

Captain’s altimeter setting

Question 45

What will the cabin altitude be just before touchdown?

Answer 45

Cabin altitude decrease to slightly below FMC planned landing altitude

Question 46

What happens to the outflow valves at touchdown?

Answer 46

Both valves open to depressurise the cabin

Question 47

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

Answer 47

a. The cabin descends to the target altitude during climb b. The cabin climbs to 6,000ft and before arrival climbs to destination elevation

Question 48

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

Answer 48

They close to preserve cabin pressure

Question 49

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

Answer 49

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

Question 50

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

Answer 50

30 seconds

Question 51

What supplies bleed air?

Answer 51

The engines.

Question 52

What is bleed air used for?

Answer 52

Engine core and inlet cowl anti–ice operations.