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M11 new josh > 11.4 air con/cabin pressure > Flashcards

11.4 air con/cabin pressure Flashcards

1
Q

where is an aircrafts pressurised air received from

A

engines, APU, Ground source

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2
Q

what happens to temperature as pressure increases

A

temperature increase

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3
Q

what stage in the engine is the compressed air taken from

A

compressor

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4
Q

when is low pressure air used

A

take off, climb, cruise

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5
Q

when is high pressure air used

A

low engine RPM

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6
Q

how many bleed ports will be open at a time

A

1

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7
Q

what is air pressure controlled by

A

pressure regulating valve or bleed air valve

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8
Q

if we use bleed air from the compressor what it there a reduction in

A

engine performance

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9
Q

what is used for cabin pressure to prevent usage of the engines air

A

independent cabin compressor

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10
Q

cabin compressors are divided into what 3 groups

A

positive displacement compressor, centrifugal compressor, turbo compressor

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11
Q

what does CAC stand for

A

cabin air compressor

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12
Q

to meet high demands for ground power when the engines arent running what is used

A

APU

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13
Q

what type of engine is a typical APU

A

small turbine engine

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14
Q

if an APU is used in flight what the bleed extraction limited to (height)

A

22,000ft

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15
Q

what is the ACP

A

air conditioning pack

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16
Q

if an aircraft doesnt have any engine on or APU running whats used for the air supply

A

pneumatic ground cart

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17
Q

what does ACS stand for

A

air conditioning system

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18
Q

whats the approximate cruising temp

A

-40 degrees celcius

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19
Q

whats the function of the air conditioning system

A

maintain comfortable air temperature in the aircraft

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20
Q

what range of temps can most ACS produice

A

21-27 degrees celcius

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21
Q

what are the 2 types of ACS system used on aircraft

A

air cycle machine, vapour cycle machine

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22
Q

where are air cycle machines commonly used

A

passenger aircraft

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23
Q

where are vapour cycle machines used

A

small and medium sized aircraft

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24
Q

what are the functions of the ACS

A

ventilation, heated air, cooled air, cabin pressure, equipment cooling

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25
whats the size of the hose off the pneumatic cart
4 inch diameter
26
where does the air cycle conditioner get its air from
engine bleed air or APU
27
where is the air cycle conditioner usually located
lower fuselage or tail section
28
at extreme altitudes the bleed air is extremely hot, what does it use to cool the air
air cooling system
29
air arriving from the bleed air system and entering the heat exchange has an average psi of what and what temperature
30 to 40 psi, 150 degrees celcius
30
what does bleed air temp reduce to after passing the heat exchanger
100 degrees celcius
31
what temp is the bleed air after entering the compressor
30 to 40 degrees celcius
32
what temp is the bleed air after going through the secondary heat exchanger
60 - 70 degrees celcius
33
what does the pack or flow control valve do
regulates bleed air from the pneumatic manifold into the air cycle machine
34
how are pack flow and control valved controlled and operated
controlled electrically, operated pneumatically
35
what type of valve is the pack valve
venturi type butterfly valve
36
what is the main function of the pack valve
control the airflow into the cabin
37
at 8000 ft what is the mass air flow into the cabin
0.86 kg/s
38
on the ground what is the mass air flow into the cabin
1.1 kg/s
39
how are air conditioning systems able to save energy
adjusting their air output to number of passengers
40
what is the ACM
air cycle machine
41
what are the 2 types of ACMs used
oil lubricataed, air lubricated
42
what are the 2 functions of the condenser/reheater
cool air in AC pack, heat air in AC pack
43
whats the use of trim air valves
accurate temp controlled air
44
where is the RAM air door located
underside of aircraft
45
what are the 5 components of a vapour cycle machine
refrigerant, compressor, condenser, expansion valve, evaporator
46
what is the refrigeration process in order
compression, condensation, receiver dryer, expansion, evaporation, repeat
47
where is the receiver dryer located in a vapour cycle system
downstream of the condenser and upstream of the expansion valve
48
what are the majority of evaporators constructed from
copper or aluminium tubing
49
what is conditioned air distributed through
ducts
50
on modern turbine powered aircraft what is conditioned air also used for
cabin pressurisation
51
during long distance flights what is likely to happen to the air
becomes very dry after being repeatedly recycled
52
what do humidifiers do for the passengers
hydration, better taste, sleep quality, reducing jet lag
53
what percentage of the cabin air is normally filtered and recirculated
50%
54
whats the use of the cabin outflow valve
controls cabin pressure by controlling the release of air
55
what are the 2 safety valves
positive, negative
56
what is the use of the positive safety valve
relives positive cabin pressure when maximal is exceeded
57
when will the positive safety valve open (psi)
maximum between 8-10 psi
58
what do negative relief valves do
prevents excessive negative differential
59
what way do positive relief valves open
outward
60
what way do negative relief vales open
inward
61
simply describe negative/positive relief valves
negative - under pressure so puts more air in positive - over pressure so reliefs
62
at what psi will negative relief valves open
0.5-1 psi
63
what valves are used to quickly dump air and air pressure from the cabin
dump valves
64
name the 3 pressurisation gauges/indicators
cabin altimeter, cabin rate of climb, cabin differential pressure
65
what are the 2 modes of pressurisation system operation
auto (1 and 2) and manual
66
how many controllers are in use at any time in the pressurisation system
1
67
during taxi what is the pressurisation GROUND/FLIGHT switch on
FLIGHT
68
during take off/climb what controls the amount of cabin pressure to altitude
outflow valve
69
in cruise does the cabin pressure change
no it stays constant
70
what does the cabin pressure controller do
controls cabin air pressure
70
what type of controls do modern aircraft use for cabin pressurisation control
pneumatic, electrical, electronic
71
on modern aircraft how many cabin pressure controller are there
two controllers, or 1 with a redundant circuitry
72
what is the ADC
air data computer
73
what is the FMS
flight management system
74
what is the best type of leak detector in air conditioning systems
electronic leak detector
75
the best leak detector of a air con system could detect what leakage per year
1/2 ounce
76
what leak detection methods other than a detector can be used
soapy solution, leak detection dye
77
what is R12
non-toxic and non-flammable gas, toxic to ozone layer
78
whats the main type of servicing equipment for vapour cycle air
manifold
79
on the manifold air vapour servicing machine whats the lower pressure/high pressure gauges psi range
low 0 - 150 psi high 0 - 500 psi
80
what colour is the low pressure hose on the air vapour servicing manifold
blue
81
what colour is the high pressure hose on the air vapour servicing manifold
yellow
82
to ensure all water is removed from a vacuum pump how long is it help before use
15-30 mins
83
what is an aircraft bleed air leak
uncontrolled loss of bleed air from any system
84
what is a major concern with pressurisation and air con systems
temperature
85
if overheat was to happen at what temp will an OVERHEAT warning display
pack overheat - 260 plus outlet temp - 230 plus
86
why is low cabin humidity good and bad
prevents bacteria and fungus, promotes fatigue and dehydration
87
on the central warning panel what do all 4 colours mean
red - warning amber - caution green - advisory white - advisory
88

M11 new josh (23 decks)

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