Air Conditioning and Pressurisation Flashcards

1
Q

How may air conditioning packs are installed?

A

2

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2
Q

Is a single pack enough to satisfy the requirements?

A

Yes

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3
Q

Which pack supplies which area?

A

Pack 1 flight deck into common duct

Pack 2 cabin

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4
Q

What conditions must be met or a pack valve to open?

A

at least 10PSI in bleed system

no auto shut off and no overheat

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5
Q

When will auto shutoff of both packs occur?

A
  • on ground during engine starting or both thrust reversers are unlocked
  • if engine failure is detected during takeoff or in flight at altitudes below 13500ft and a thrust lever setting above MIN takeoff is selected
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6
Q

How is pack operation restored after an auto shutdown due engine failure?

A

by operating AIRCOND AUTO SHUT pb or by selecting a lower thrust setting. Will be automatically restored when climbing above 13500ft.

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7
Q

How are normal and economy flows selected?

A

manually via ECON pb. ECON is achieved when both pack valves are open and the auto controlled cabin temp is within a preset range from the selected temp.

economy is automatic during:

  • takeoff, normal is restored 1 min after takeoff
  • upon TOGA activation, restored after 1 minute
  • as long as max TO thrust is selected
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8
Q

What is augmented flow?

A

operative when one pack is manually switched OFF

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9
Q

If you are in economy mode and a pack fails, what happens?

A

Normal , then when off, goes to augmented mode.

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10
Q

How do you select a cabin or flight deck temperature?

A

via the temperature selectors.

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11
Q

Where is air temperature displayed?

A

on air con panel

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12
Q

How is the flight deck and cabin air distributed?

A

flight deck: via air outlets on side walls, ceiling, pedestal and floor

cabin: cabin wall,

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13
Q

How many re-circulation fans are there, what do they do and how are they controlled?

A

4 fans. mounted in cabin ceiling to recirculate air, controlled by RECIRC FANs pb.

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14
Q

How and when would you introduce RAM air into the aircraft?

A

when unpressurized

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15
Q

What happens to the air con system if an engine failure occurs above 13500ft and below?

A

assuming thrust lever above MIN TO is selected:
If above, econ mode.
If below, both packs auto shut off.

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16
Q

Is there any time the automatic switch to economy flow will not work?

A

When both in manual mode, econ is inhibited. ECON is only possible to select when both pack valves are open and the auto controlled cabin temp is within a preset range from the selected temp.

17
Q

If an external air con unit is supplying ventilated air, what precautions must you take and why?

A

must open avionics hatch to prevent pressurisation of aircraft that prevents opening doors and windows.

alternative open sliding window before it is connected

18
Q

What would you do to reduce cabin air temperature during ground ops and initial flight?

A
  • before landing start the APU
  • select the APU off shortly before TO
  • during ground ops with cabin air supply select the recirc fans off if OAT is above 15 degrees
  • during ground ops keep blinds closed
  • select air con ECON mode off when passengers are boarding
19
Q

What is normally operating maximum differential pressure as applied by the controller?

A

7.46psi

20
Q

At that max differential pressure by the controller, what is cabin altitude at 35000?

A

8000ft

21
Q

What is the differential pressure limited by the outflow valves?

A

7.65psi and cabin alt 12000 +- 1500ft

22
Q

What is the altitude limiter set to?

A

cabin alt 12000 +- 1500ft

23
Q

What warnings is there of excessive cabin altitude?

A

Level 3 alert CABIN ALT when above 10000ft

24
Q

How is the fuselage protected aginst negatvie pressure?

A

via two inward pressure relief valves

25
Q

How do you set the panel for automatic operation?

A

ensuring PRESS CONTROL button is blank

26
Q

What happens if the active pressure controller channel fails?

A

secondary provides automatic control

27
Q

How do you manually change channels on the pressure controller?

A

by pressing PRESS CONTROL pb twice in succession

28
Q

What happens if both pressure controllers fail? what do you do?

A

The system auto reverts to manual mode. FOllow QRH and press PRESS CONTROL to ensure manual operation

29
Q

How do you control pressurization in manual?

A

if climbing
MAN
manu control lever UP
manual rate controller as req

when at CAB ALT
MID POS

if descending
DN
manual rate controller as req

30
Q

What pressurization alerts are there and at what level?

A

CABIN PRESS CTL CHAN Alert1
CABIN PRESS CTL Alert 2
CABIN ALT alert 3