Chapter 2 Air systems Flashcards

1
Q

What will cause a BLEED TRIP OFF Light?

A

If the engine bleed air temperature OR pressure has been exceeded.

(FCOM 2.20.1)

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2
Q

What will cause a ‘PACK TRIP OFF’ light to illuminate?

A

Respective pack has exceeded temperature limits and has tripped off

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3
Q

What does amber ‘EQUIPMENT COOLING OFF’ Light indicate?

A

Loss of airflow due to failure of an equipment cooling fan.

There is no airflow detected coming from the respective cooling exhaust

(FCOM 2.31.7)

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4
Q

How many packs are required to maintain pressurisation up to FL410 ?

A

A single pack IN HIGH flow is capable of maintaining pressurization up to the maximum certified ceiling.

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5
Q

When the aircraft is on the ground or the flaps are down with the packs in AUTO, will the packs still automatically change to high flow, if operating on one pack only?

A

No, automatic switching to high air flow is inhibited in this situation to ensure adequate engine power is available for single engine operations.

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6
Q

What is the purpose of operating the packs in AUTO during normal operations in flight?

A

Incase one pack stops supplying air, the remaining pack automatically switches to high air flow to increase ventilation.

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7
Q

What is is the purpose of the Ram Air System?

A

Provides cooling air for the heat exchangers.

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8
Q

How is the Ram Air System controlled and operated?

A

The system is automatically controlled by the packs through the operation of the ram inlet doors.

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9
Q

What are the four steps of the cooling cycle?

A
  1. Bleed air passes through heat exchanger for cooling.
  2. Air then flows to Air Cycle Machine for refrigeration and water separation.
  3. The cold air is then ‘conditioned’ and combined with hot air.
  4. The conditioned air is then distributed by the mix manifold.
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10
Q

What happens to the Air Mix valves if the pack valves close and why?

A

The air mix valves drive to full cold position in order to aid startup of the cooling cycle and prevent hot air trips when the packs are turned back on.

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11
Q

What is the purpose of the Recirculation fans?

A

To reduce engine bleed air demand and air conditioning system pack load.

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12
Q

What happens to the Equipment cooling exhaust fan if there is a Forward Cargo Fire warning?

A

The equipment cooling exhaust fan SHUTS OFF, and the ‘OFF’ light is inhibited.

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13
Q

How many automatic cabin pressure controllers are fitted to INU?

A

Two

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14
Q

How is the pressurisation controlled?

A

By modulating the outflow and overboard exhaust valve.

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15
Q

What is the purpose of the PRESSURE RELIEF VALVES?

A

To provide safety pressure relief incase the cabin differential pressure EXCEEDS 9.0 PSI.

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16
Q

What is the maximum cabin differential pressure?

A

9.1PSI

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17
Q

How many pressure relief valves are there and what are they called?

A

Two, a pressure relief and one negative relief valve.

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18
Q

Where do BOTH the Cabin Pressure controllers receive their altitude and pressure data from?

A

ADIRU’s, which receives barometric corrections from the BARO reference selectors (QNH)

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19
Q

Why does the outflow valve modulate towards ‘closed’ position when thrust is increased during the take off roll?

A

Ground pressurization of the cabin makes the transition to pressurized flight more gradual for the passengers, and also gives the system better response to ground effect pressure changes during takeoff.

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20
Q

What are the pressurisation controllers programmed to do if the amber ‘OFF SCHED DESCENT’ light illuminates?

A

The controller programs the cabin to land at the takeoff field elevation without further pilot inputs. (Assumes return 4 landing)

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21
Q

What happens if the FLT ALT indicator is changed, after an amber ‘OFF SCHED DESCENT’ light illuminates?

A

The automatic abort capability to the original takeoff field elevation is lost.

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22
Q

What happens if the FLT ALT indicator is changed, after an amber ‘OFF SCHED DESCENT! light illuminates?

A

The automatic abort capability to the original takeoff field elevation is lost.

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23
Q

What triggers pressurisation to change from climb, cruise or descend mode?

A

When the airplane climbs or descends to within/outside of 0.25 psi of the selected FLT ALT.

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24
Q

When is manual control of the cabin altitude required?

A

If both the AUTO and ALTN modes are inoperative or during a non-normal situation.

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25
Q

How is the pressurisation controlled when in Manual mode?

A

By manually positioning the outflow valve using the Outflow Valve switch.

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26
Q

DELETE

A
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27
Q

How should the outflow valves be treated when manually opening or closing the valve?

A

A very small movement of the outflow valve is recommended at one time.

A small movement of the outflow valve can cause a large change in cabin rate of climb or descent. Manual actuation of the outflow valve can produce large, rapid changes in cabin pressure which could result in passenger and crew discomfort and/or injury.

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28
Q

Is Pre conditioned air delivered directly to the LEFT, RIGHT or MIX manifold?

A

MIX MANIFOLD

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29
Q

With the Isolation valve in ‘AUTO’, what is the expected normal position of the valve and what will change this?

A

CLOSED, if any of the bleed or packs switches are placed ‘OFF’ (This action will open valve).

Note: The valve should normally be closed, however if one of the sides l

(FCOM 2.20.2)

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30
Q

If the ‘WING BODY OVER HEAT’ lights up, which side (L or R) indicates a bleed air duct leak from the APU?

A

LEFT (FCOM 2.10.3)

Note: The KEEL BEAM and APU BLEED DUCT has a sensor.

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31
Q

Where is the Bleed Air DUCT PRESSURE measured?

A

Bleed air duct (piping/passage)

32
Q

What normally happens when the Air Conditioning PACK Switch are placed to ‘AUTO’?

A

Each pack regulates to low flow (FCOM 2.10.6)

33
Q

What happens when the Air Conditioning PACK Switch are placed to ‘AUTO’ and one pack fails?

A

Operating pack regulates to high flow in flight if are flaps up (not during approach)
(FCOM 2.10.10)

34
Q

What does the ‘CONT CAB’ temerature indicate?

A

The flight deck (FCOM 2.10.10)

35
Q

What would a decrease on th outer scale (diff pressure) and INCREASE on the inner scale (cabin alt) on the Cabin Altitude Panel indicate?

A

Cabin pressure in dropping, the cabin altitude is climbing which is an indication of the depressurising.

36
Q

At what cabin altitude does the ALT HORN activate?

A

FL100 (FCOM 2.10.14)

37
Q

What does an AMBER ‘AUTO FAIL’ Light indicate?

A

Dual controller failure when illuminated alone

38
Q

What does an AMBER ‘AUTO FAIL’ AND a ‘ALTN’ Light indicate?

A

Single controller failure when ALTN light is also illuminated (FCOM 2.10.14)

39
Q

What does “88888 ( 5 eights)” indicate on the pressurisation control panel indicate?

A

A panel failure detected or a DC power interruption (FCOM 2.10.14)

Note: FLT ALT indicator failure may result in the display of non-numbers or a
blank display. If the indicator cannot be changed by rotating the flight
altitude selector, it may be necessary to monitor the pressurization system
to ensure normal operation, especially during climb and descent.

40
Q

What are possible ways bleed air can be supplied to the engines for starting?

A
  1. Opposite Engines (If its running),
  2. APU, or
  3. External air cart/source.

(FCOM 2.20.1)

41
Q

What is bleed air used for?

A
  1. Air conditioning/pressurization
  2. Wing and engine thermal anti-icing
  3. Engine starting
  4. Hydraulic reservoirs pressurization
  5. Water tank pressurization
  6. Nitrogen Generating system (NGS)
    (FCOM 2.20.2)
42
Q

What fan stages of the engine supply bleed air?

A

5th and 9th stages.

When 5th stage low pressure bleed air is insufficient for the bleed air system requirements, the high stage valve modulates open to maintain adequate bleed air pressure.
(FCOM 2.20.1)

43
Q

What causes the ‘BLEED TRIP OFF’ light to illuminate and what happens?

A

Engine bleed air TEMP or PRESSURE limits were exceeded. The respective engine bleed air valve closes automatically. (FCOM 2.20.1)

44
Q

How is the APU valve CLOSED?

A
  1. Manually by placing the APU bleed valve to ‘OFF’
  2. Automatically when the APU is turned off.
    (FCOM 2.20.2)
45
Q

Is the ISOLATION valve DC or AC operated?

A

AC
(FCOM 2.20.2)

46
Q

What causes the ‘DUAL BLEED’ light to illuminate?

A

Whenever the APU bleed air VALVE IS OPEN and the position of the engine bleed air switches (Note one is position of valve and the other is position of switch) and isolation valve would permit possible backpressure of the APU (not in closed configuration).

(FCOM 2.20.2)

47
Q

What causes ‘Wing Body overheat’ light to illuminate?

A

A bleed air duct leak. It is sensed by
the overheat sensors (FCOM 2.20.7)

48
Q

Where does the cockpit get its airconditioned air from (Which pack/Engine supplies the conditioned air) ?

A

Conditioned air from the LEFT PACK, upstream of the mix manifold, flows directly
to the flight deck. (FCOM Vol2 2.30.1)

49
Q

How many packs can the APU supply bleed air to in the air?

A

One (FCOM Vol2 2.30.1)

50
Q

Can one engine operate more than one pack?

A

No (FCOM Vol2 2.30.1)

51
Q

What happens if the air conditioning pack
switches are set to HIGH?

A

the packs provide high air flow to increase ventilation. (FCOM Vol2 2.30.1)

52
Q

Scenario: Aircraft is in flight with flaps up / Not on approach. What happens if a pack fails? (Note: Normally both bleed switches ‘ON’, and both air conditioning pack switches are set to AUTO)

A

The remaining pack automatically switches to high air flow to increase
ventilation. (FCOM Vol 2 2.30.1)

Note: An engine failure or if pack is turned off, this will also result in a pack cessation and similar reaction.

53
Q

Scenario: Aircraft is on approach with flaps extended. What happens if a pack fails? (Note: Normally both bleed switches ‘ON’, and both air conditioning pack switches are set to AUTO)

A

the remaining pack will not automatically switch to high air flow.

Note: This ensures maximum performance available incase of engine failure.

54
Q

What is the funtion of the RAM AIR SYSTEM and how are they operated?

A

Provides cooling air for the heat exchangers, operated automatically by the packs through operation of ram air inlet doors. Generally the doors will be closed during cruise and open on the ground or slow flight .

55
Q

How do you know if the Ram doors are open?

A

a “RAM DOOR FULL OPEN” light illuminates whenever a ram door is fully open. (BLUE)

56
Q

How does the Airconditioning ‘Cooling cycle’ work?

A

Four steps:
1. Bleed air passing through a heat exchanger for cooling.
2. Then air then flows to an air cycle machine for refrigeration
3. Then to a water separator which removes moisture.
4. The processed cold air is then combined with hot air.
Once air is cooled, the conditioned air flows into the mix manifold and distribution system.
(FCOM Vol 2 2.30.2)

57
Q

What happens when the airconditioning overheats?

A

Overheat protection is provided by temperature sensors located in the cooling
cycle. An overheat condition causes the pack valve to close and the ‘PACK TRIP
OFF’ light to illuminate
(FCOM Vol 2 2.31.2)

58
Q

What do the Recirculation fans do?

A

reduces the air conditioning system pack load and the
engine bleed air demand.

(FCOM Vol 2 2.31.5)

59
Q

What is the temperature rang of the Zone Temp control?

A

18�(C) - 30�(W) Celcius

60
Q

If both PACK switches are placed to “HIGH” on the ground, does the recirculation fan continue to operate?

A

the LEFT recirculation fan stops operating and the
right recirculation fan CONTNUES operating. (FCOM Vol 2.31.7)

Note: Placing a single pack to ‘HIGH’ will not have an effect.

61
Q

What does the equipment cooling system do?

A

cools electronic equipment in the flight deck and
the E & E compartment.

62
Q

What will cause an ‘EQUIPMENT COOLING OFF’ light to illuminate?

A

Loss of airflow due to failure of an equipment cooling fan.

Note: Selecting the alternate fan
should restore airflow and extinguish the OFF light within approximately 5
seconds.

63
Q

How sis the cabin pressure controlled?

A

By the cabin pressure control system. The system uses bleed air supplied to and distributed by the air conditioning system. Pressurization and ventilation are controlled by modulating the outflow
valve and the overboard exhaust valve.

64
Q

What protects the aircaft from over pressurisation?

A

Two pressure relief valves provide safety pressure relief by limiting the
differential pressure to a maximum of 9.1 psi. A negative relief valve prevents
external atmospheric pressure from exceeding internal cabin pressure.

65
Q

What three modes does the pressurisation mode selector offer?

A

Auto, Alternate and Manual (AUTO/ALTN/MAN)

66
Q

Where does the pressurisation mode selector receive its data from?

A

ADIRU’s and SMYD’s. The air data inertial reference units (ADIRUs) provides ambient static pressure,
baro corrected altitude, non-corrected altitude and calibrated airspeed to both
automatic controllers. The controllers also receive throttle position from both stall
management computers and signals from the air/ground sensors.

67
Q

How is the pressurisation controlled normally?

A

The airconditioning system supplies pressurisation to the cabin, and the outflow valve is the overboard exhaust exit for the majority of the air
circulated through the passenger cabin. This ensures contant pressurisation.

68
Q

What happens to the overboard exhaust valve if either PACK switch is placed to ‘HIGH’? Note: Placing both PACK switches to HIGH, will cause the left RECIRCULATION fan to stop.

A

the overboard exhaust valve is driven OPEN if either pack switch is in
high AND the RIGHT recirculation fan is off. This allows for increased ventilation in the
smoke removal configuration.

69
Q

How does the Pressurisation system know the aircraft is on the ground or In flight?

A

The air/ground safety sensor signals whether the airplane is on the ground or in
the air.

70
Q

What will cause an amber OFF SCHED DESCENT light to illuminate?

A

if the airplane begins to descend without having reached the preset cruise altitude

71
Q

What does the pressurisation system do if a flight was aborted in climb and returned to the takeoff airport?

A

The controller programs the cabin to land at the takeoff field elevation without further pilot inputs.

Note: If anything is changed on the the panel such as the cruise altitude, the system will not set the take off altitude that was preprogrammed.

72
Q

What six things will cause the AUTO FAIL light to illuminate?

A
  1. Loss of DC power
    2.Controller fault
  2. Outflow valve control fault
  3. Excessive differential pressure (> 8.75 psi)*
  4. Excessive rate of cabin pressure change (�2000 sea level feet/minute)*
  5. High cabin altitude (above 15,800 feet) (If controller is not responding properly)

(FCOM 2.40.5)

73
Q

What is the quickest qay to close the outflow valve?

A

Selecting MAN (Manual) on the pressurisation mode selector and manually opening the outflow valve.

74
Q

Why does the MAN mode open the outflow valve quicker?

A

It uses a separate DC motor, powered by the DC standby system.

Note: This faster movement of the outflow valve allows the crew to quickly depressurize the
airplane during non-normal situations.

75
Q

How long does it take to manually open the outflow valve from fully closed position (Full range of motion)

A

20 seconds (FCOM 2.40.6)