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Flashcards in Pressurization Deck (37)
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1
Q

Pressurization and ventilation are primarily controlled by which two valves?

A

Outflow valve and the Overboard Exhaust Valve.

2
Q

Where is the outflow valve?

A

Rear of the aircraft

3
Q

Where is the overboard exhaust valve?

A

underneath the aircraft kind of aligned with forward doors.

4
Q

How many automatic pressurization controllers are there?

A

2 installed.

5
Q

The outflow valve is controlled automatically when in either ____ or _____ pressurization modes.

A

AUTO or ALTN.

6
Q

When does the CLOSE/OPEN switch for pressurization?

A

Only when the selector switch is in MAN.

7
Q

T/F: The outflow valve indicator always shows the position of the outflow valve

A

true.

8
Q

T/F: The initial planned cruising altitude should be set in the Flight Altitude indicator prior to takeoff.

A

true.

9
Q

Every click of the Flight Altitude selector knob adjusts indication by _____feet over a range of _____ to ______feet.

A

500, -1000 feet, 42,000 feet.

10
Q

T/F: The intended landing airport altitude should be set before takeoff.

A

True

11
Q

What lights come on for a single failure of a pressurization controller?

A

AUTO FAIL AND ALTN (green light) lights come on.

12
Q

What lights come on for a dual failure of pressurization controllers?

A

Just the amber AUTO FAIL light comes on.

13
Q

What pilot action causes the green ALTN light to come on?

A

moving the pressurization selector switch to ALTN.

14
Q

What causes the amber OFF SCHED DESCENT light to come on?

A

the aircraft descends prior to reaching the preset cruise altitude.

15
Q

What causes the green MANUAL light to come on?

A

moving the pressurization selector switch to MAN.

16
Q

What causes the intermittent cabin altitude warning horn to come on.

A

Cabin altitude exceeds 10,000 feet. The horn can be silenced by pressing the ALT HORN CUTOFF button.

17
Q

How many positive pressure relief valves are there and what do they do?

A

2 valves in the right rear of aircraft. They limit the max pressure differential to 9.1 PSI.

18
Q

How many negative pressure relief valves are there and what do they do?

A

1 valve in right rear of aircraft. Prevent atmospheric pressure exceeding internal cabin pressure which can sometimes occur with a very rapid descent from altitude.

19
Q

What types of motors are used to control the outflow valve in all cabin pressure controller modes?

A

DC motors. Ensure operation in event of AC failure.

20
Q

Where do the Cabin Pressure Controllers get their info from? What info do they use?

A

Air Data Inertial Reference Units (ADIRUs).

Ambient static pressure,
barometric corrected altitude
non-corrected altitude
calibrated airspeed.

Other inputs:
Throttle position via both stall management computers
Signals from the Air ground sensing system.

21
Q

How does cabin air normally leave the aircraft in flight?

A

conditioned cabin air exits through foot grills and is then routed to provide heating for aft cargo compartment and then to the outflow valve.

22
Q

What two things cause the overboard exhaust valve to open or close

A

differential pressure and air/ground status.

23
Q

If there is low differential pressure in air or ground, how is the Overboard Exhaust valve positioned?

A

open and warm air exits from the E&E bay overboard.

24
Q

If there is high differential pressure in air, how is the Overboard Exhaust valve positioned?

A

valve is closed and air is diffused to the lining of the forward cargo compartment.

25
Q

If either pack is in ____ and the ___ RECIRC FAN is OFF, the overboard exhaust valve is driven ____ to provide increased ventilation in the smoke removal configuration.

A

HIGH, R, open.

26
Q

What modes on pressurization do the FLT ALT and LAND ALT need to be set before flight?

A

AUTO and ALTN.

27
Q

The outflow valve is fully open to depressurize the aircraft on the ground during ________________.

A

lower power settings.

28
Q

When does cabin pressurization begin?

A

on the ground with higher power settings.

29
Q

If you make a return to your takeoff airport before reaching planned cruise altitude, do you need to set the landing altitude?

A

No, the altitude is retained in memory.

30
Q

When does the pressurization controller transition to the cruise phase of flight?

A

When the a/c reaches an altitude within 0.25 PSI of the selected flight altitude.

31
Q

The pressurization controller always strives to maintain the cabin altitude slightly below the selected____________.

A

landing altitude. IF not possible, a target differential pressure and cabin altitude based on selected flight altitude.

32
Q

When does the pressurization controller switch to the descent phase?

A

when the plane descends 0.25 PSI below the selected flight altitude.

33
Q

T/F: you land slightly pressurized?

A

True.

34
Q

What causes the AUTO FAIL light to come on?

A

Loss of DC Power
Controller Fault
Outflow valve control fault
Excessive diff pressure (>8.75 PSI)
Excessive rate of cabin pressure change (+/-2000 sea level feet/min)
High cabin altitude (above 15,800 feet)* if controller not responding properly.

35
Q

What is the difference in MAN mode vs AUTO or ALTN for pressurization?

A

Full control. MAN has a separate DC motor powered by the DC standby system. The rate of change of the valve is slower in MAN mode. Full travel range time is 20 seconds.

36
Q

T/F: Control of cabin altitude may be regained by increasing thrust on ensure a sufficient supply of air.

A

True.

37
Q

If cabin altitude is not controllable:

A

Don mask and set regulators to 100%
Establish crew communication

If cabin altitude might or has exceeded 14,000 ft:
PASS OXYGEN switch ON
Passenger signs ON
Do Emergency Descent Checklist.