11.4 Air Conditioning

Question 1

Air supply sources

Answer 1

Engine
APU
ground pneumatic cart

Question 2

Emergency ram air system purpose

Answer 2

Ventilate cockpit and cabin if all packs fail

Question 3

ATA 36

Answer 3

Pneumatics

Question 4

ATA 21

Answer 4

Air con

Question 5

HEPA

Answer 5

High efficiency perticulate air filter

Question 6

Ideal temp

In cabin

Answer 6

Between 70 and 80f

Or 21 and 27c

Question 7

Ideal humidity

Answer 7

30%

Question 8

How many pounds of fresh air per minute in cabin

Answer 8

0.55lbs fresh air per person per minute

Question 9

HEPA filter efficiency

Answer 9

85 to 99.995%

Question 10

Aircraft cooling systems

Answer 10

• Vapour cycle cooling system( small aircraft)

* air cycle cooling system ( large aircraft)

Question 11

Vapour cycle cooling system systems:

• compressor

Answer 11

When vapour compressed its pressure and temp increases

Question 12

Vapour cycle cooling system systems:

• condenser

Answer 12

Condenses hot refrigerant gas from compressor

Question 13

Vapour cycle cooling system systems:

• the reciever dryer

Answer 13

Serves as resevoir for liquid refrigerant

Question 14

Vapour cycle cooling system systems:

• the theromostatic expansion valve

Answer 14

Regulates the amount of liquid flowing into evaporator

Question 15

Vapour cycle cooling system systems:

• the evaporator

Answer 15

Absorbs the heat of aircraft cabin into refrerant . As heat abaorbed the refrigerant evaporates

Question 16

Vapour cycle cooling system systems:

• refrigerant

Answer 16

You want a refrigerant with low boiling point so it turns to vapour quicker

Question 17

Air cycle cooling system

Answer 17

AKA air conditioning packs , installed in newest aircraft

Question 18

Air cycle cooling system ( systems )

• flow control valve

Answer 18

AKA pack valve

Question 19

Air cycle cooling system ( systems )

• air cycle machine (ACM)

Answer 19

Consists of turbine which drives compressor , compressor increases pressure and temp

Question 20

Air cycle cooling system ( systems )

• turbine by pass valve

Answer 20

Controls pack outlet temp

• AKA temp control valve

Question 21

Air cycle cooling system ( systems )

• water seperator valve

Answer 21

Collects excess moisture before it enters the cabin

Question 22

Air cycle cooling system ( systems )

• pack anti ice valve

Answer 22

Removes and prevents ice at turbine outlet and water seperator

Question 23

Air cycle cooling system ( systems )

• ram air inlet and outlet doors

Answer 23

Used to control amount of cooling airflow across the heat exchanger

Question 24

Air cycle cooling system ( systems )

• fan bypass check valve

Answer 24

It opens if amount of ram airflow is higher than the cooling fan delivers

Question 25

Where is aircraft most efficient

Answer 25

High altitude

Question 26

Cabin climb rate?

Answer 26

500 feet per minute (max)

Question 27

Descent rate?

Answer 27

300 feet per minute (max)

Question 28

How is cabin altitude measured

Answer 28

Adding ambient pressure to pressure inside aircraft

Question 29

Where is outflow valve when plane is landed?

Answer 29

Fully open

Question 30

Pressurisation control systems: | • outflow valve

Answer 30

• Modulates cabin air

Question 31

Pressurisation control systems: | • pressure controller

Answer 31

Provides control signals to the outflow valve ac motors

Question 32

Pressurisation control systems: | • control panel

Answer 32

Contains all necessary selectors and indicators for the fligjt crew to operate the pressurisation system.

Question 33

Excessive rate of cabin altitude:

Answer 33

Greater than 3100 feet per minute or descend greater than 2000 feet per minute

Question 34

Safety and warning devices: | • pressure relief valves

Answer 34

Designed to open if too much pressure difference

Question 35

Safety and warning devices: | • negative relief valves

Answer 35

* AKA vacuum relief valves | * equalise a possible negative pressure difference duriny descent

Question 36

Safety and warning devices: | • pressure system monitoring

Answer 36

* At 10,000 feet warning for cabin altitude | * at 14,000 oxygen masks drop

Question 37

Purpose of emergency ram system

Answer 37

Ventillate cockpit if packs fail

Question 38

Why cant air con packs be used at the same time

Answer 38

High cabin airflow may damage the air con ducts

Question 39

What component extracts cabin air

Answer 39

Evaporator

Question 40

Max pressure in aircraft is determined by?

Answer 40

Strength of cabin

Question 41

To decrease cabin altitude:

Answer 41

Outflow valves must be closed

Question 42

Purpose of pack valves

Answer 42

Allows certain amount of bleed air from engine through to the pack system and as trim air

Question 43

% of air recirculated

Answer 43

30-55

Question 44

How is temp in cabin controlled

Answer 44

Through a pack : vapour syetem, air cooling system

Question 45

What is charge air

Answer 45

Bleed air from engine

Question 46

What is ram air

Answer 46

Air used to cool packs

Question 47

Boot strap system?

Answer 47

Pack system ( air cycle cooling system )

Question 48

How is air distributed into cabin and cargo bays

Answer 48

Exit louvers

Question 49

Location of trim air valve

Answer 49

Downstream of the packs

Question 50

Components of air cycle machine (acm)

Answer 50

Turbine , compressor , cooling fan

Question 51

Purpose of thermostatic expansion valve

Answer 51

Regulate liquid flowing into evaporator

Question 52

What controls cabin pressure

Answer 52

Outflow valve

Question 53

Purpose of dessicant in reciever dryer?

Answer 53

Absorbs moisture from refrigerant

Question 54

Purpose of turbine

Answer 54

Drives compressor