Pressurisation Flashcards

1
Q

How the pressurisation system is controlled ?

A

It can be controlled automatically - semi automatically and manually

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2
Q

How many CPC ?

A

There are 2 independant Cabin Pressure Controllers

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3
Q

What kind of data do the CPC use ?

A

Multiple data : landing elevation, QNH from FMGS, position of the thrust levers, position of the landing gear, pressure altitude from the ADIRS to control the and optimize the cabin altitude

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4
Q

What is the maximum cabin altitude under normal conditions ?

A

8000ft

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5
Q

How many pressurisation modes does the system have ?

A

4 modes :
- Ground
- Pre-pressurisation
- Pressurisation in flight
- Depressurisation

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6
Q

What is the Ground mode ?

A

It fully opens the outflow valve on the ground

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7
Q

What is the Pre-pressurisation mode ?

A

During takeoff, it decreases the cabin pressure to avoid surge during rotation.

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8
Q

What is the Pressurisation in flight mode ?

A

It adjusts the cabin altitude and rate of change to provide passenger with a confortable flight.

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9
Q

What is the Depressurisation mode ?

A

After touchdown, it gradually releases cabin residual overpressure before the ground mode function fully opens the outflow valve.

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10
Q

When does a change of CPC occur ?

A

70 seconds after touchdown or by pressing the MODE SEL in the overhead panel for at least 10 seconds.

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11
Q

What is the outflow valve and how does it work ?

A

It consists of a rectangular body with two flaps, linked to an actuator (two automatic motor and one manual motor).
In automatic mode : the operating controller signals the position to the ECAM
In manual mode : the backup section of the CPC1 signals the position to the ECAM

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12
Q

What happens to the outflow valve when RAM air pb is ON, in automatic mode ?

A

When RAM air pb is ON and p < 1PSI, the system drives the outflow to 50% open.

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13
Q

What happens to the outflow valve when RAM air pb is ON, in manual mode ?

A

The outflow valve does not automatically open, even if p < 1 PSI

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14
Q

How many safety valve ?

A

There are 2, and located in the rear bulkhead, above the flotation line.

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15
Q

How do the safety valves work ?

A

They prevent cabin pressure from going too high (8.6PSI above ambient) or too low (1PSI below ambient)

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16
Q

What is the RPCU ?

A

Residual Pressure Control Unit, it automatically depressurises the aircraft in case of abnormal residual pressure on the ground.

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17
Q

When does the RPCU open the outflow valve ?

A

It opens automatically the outflow valve when :
- the outflow valve is not open, and
- both CPC are failed or manual mode selected, and
- the aircraft is on the ground, and
- all engine shutdown, or all ADIRS indicate speed below 100kt.

18
Q

What are the pressurisation modes under automatic control ?

A

There are 6 modes :
- Ground mode
- Takeoff mode
- Climb mode
- Cruise mode
- Descent mode
- Abort mode

19
Q

Whats is the GROUND mode under automatic control ?

A

Before takeoff and 55 secondes after landing, the outflow valve fully opens to ensure there is no residual pressure. Upon touchdown, the CPC controls the cabin descent rate to +500ft/min until the inside/outside pressures equalise.

20
Q

Whats is the TAKEOFF mode under automatic control ?

A

When N2 reaches takeoff power, the CPC pressurises the aircraft at a rate of -400ft/min until it reaches +0.1PSI to avoid surge during rotation

21
Q

Whats is the CLIMB mode under automatic control ?

A

When the main landing gear retract, the CPC controls the pressure based on the actual climb rate

22
Q

Whats is the CRUISE mode under automatic control ?

A

The maximum altitude is maintained at a constant differential pressure with a maximum cabin altitude of 8000ft and a maximum differential pressure of 8.06 PSI

23
Q

Whats is the DESCENT mode under automatic control ?

A

It is optimised so that the cabin altitude reaches the landing field pressure prior to landing at a maximum rate of 750ft/min. The aircraft is pre-pressurised, similar to takeoff at +0.1PSI in order to avoid surge

24
Q

Whats is the ABORT mode under automatic control ?

A

It prevents cabin altitude from climbing, it the aircraft stops to climb before reaching 8000ft, or initiates a descent after takeoff.
The cabin pressure resets to the value before takeoff (takeoff altitude + 0.1PSI)

25
Q

What is the semi-automatic mode ?

A

When the data from the FMGS is not available, the crew can manually select the landing elevation using the LDG ELEV knob.

26
Q

What is the range of the LDG ELEV knob ?

A

From - 2000ft below sea level to +14 000ft above sea level

27
Q

What is the manual mode ?

A

If both CPC fail, the crew must first push the MAN SEL pb, then control the outflow valve by using the MAN V/S CTL toggle to increase (UP) or decrease (DOWN) the cabin altitude.

28
Q

How many seconds can it take to notice a change of the outflow valve in manual mode on the ECAM ?

A

Up to 5 seconds

29
Q

Does the outflow valve open under manual control on the ground after landing ?

A

No

30
Q

Whats happens if DITCHING pb is pressed ?

A

When pressed, it commands the closure of the :
- outflow valve
- the emergency RAM air
- avionic ventilation inlet / outlet valves
- pack flow control valves
- forward cargo isolation outlet if installed

31
Q

Whats happens if DITCHING pb is pressed, with low ground cart connected and doors closed on the ground ?

A

It will pressurise the aircraft !

32
Q

When does the cabin altitude rate flash on the ECAM ?

A

It flashes when reaching 1750ft/min and stops flashing when returning below 1650ft/min

33
Q

When does the delta p flash on the ECAM ?

A

It flashes when delta p > 1.5PSI and stops flashing when returning at 1PSI during flight (phase 7)

34
Q

When does the delta p become amber on the ECAM ?

A

When delta p is out of normal range (<0.4PSI or >8.5PSI)

35
Q

When does the cabin altitude flash on the ECAM ?

A

It flashes when reaching 8800ft and stops flashing when returning to 8600ft

36
Q

When does the cabin altitude become red on the ECAM ?

A

When at or above 9550ft

37
Q

When does the safety valves open on the ECAM ?

A

When delta p is between 8.9PSI and 9.7PSI.

38
Q

When does the outflow valve become amber on the ECAM ?

A

When open more than 95% in flight, under automatic mode

39
Q

At what altitude the PAX SIGNS WARNING occurs ?

A

When cabin altitude goes above 11 300ft (all cabin signs illuminate)

40
Q

At what altitude the CABIN OXYGEN MASKS drop ?

A

When cabin altitude goes above 14 000ft (the masks drop automatically)

41
Q

At what altitude the OUTFLOW VALVE closes ?

A

When cabin altitude goes above 15 000ft (the actuator commands the outflow valve to the closed position)