Air Systems Flashcards

1
Q

DUAL BLEED (light)

A

Illuminated:

  • APU bleed air valve open and engine NO.1 BLEED air switch ON or
  • engine NO.2 BLEED air switch ON, APU bleed air valve and isolation valve open

illuminates when the APU Bleed Valve is open and a possibility exists that the engine bleed air could provide back pressure on the APU. So this light provides protection in the event the APU check valve should fail.

Note: The light monitors the position of the Engine Bleed Switch, (not the Engine Bleed valve). So if the APU Bleed Valve is open and the #1 Bleed Switch is ON, the DUAL BLEED light illuminates whether engine #1 is running or not.

Engines must remain in idle power when the DUAL BLEED light is on. And although the light indicates an abnormal condition, the DUAL BLEED light will be on during normal engine starting.

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2
Q

ISOLATION VALVE (switch)

A

Close = closes isolation valve

AUTO (this is the normal position):

  • closes isolation valve if both BLEED air switches are ON and both air conditioning PACK switches are AUTO or high
  • opens isolation valve automatically if either engine BLEED air or air conditioning PACK switch positioned OFF

Open = opens isolation valve

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3
Q

WING-BODY OVERHEAT light (Left or right)

A

illuminated:
LEFT light indicates overheat from bleed air duct leak in left engine strut, left inboard wing leading edge, left air conditioning bay, keel beam or APU bleed air duct

RIGHT light indicates overheat from bleed air duct leak in right engine strut, right inboard wind leading edge or right air conditioning bay

When one of these lights comes on, the MASTER CAUTION and AIR COND annunciator lights will illuminate.

Follow the WING BODY OVERHEAT Non-Normal checklist to correct this condition (Note: There is NO automatic bleed air shutoff for this system!)

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4
Q

BLEED TRIP OFF Light

A

illuminated: excessive engine bleed air temperature or pressure (protects the pneumatic system from overtemp or overpressure sensed downstream of the 9th stage bleed, but the pressure sensor is located Upstream of the Bleed Air Valve.)

  • related engine bleed air valve closes automatically (a temperature sensor will close the Bleed Valve and activate the BLEED TRIP OFF light)
  • When BLEED TRIP OFF occurs, the MASTER CAUTION lights and the AIR COND annunciator will illuminate.
  • requires reset (see below or press the TRIP RESET switch)

how to reset = pilot may reset trip reset switch if fault condition is corrected (after cooling). Note: normally the fault will correct itself since closure of the Bleed Valve allows the temperature to decrease but the BLEED TRIP OFF must be reset. (follow the QRH).

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5
Q

PACK (switch)

A

OFF = pack signaled off

Auto:

  • with both packs operating, each pack regulates low flow
  • with one pack operating, operating pack regulates to high flow in flight with flaps up (Note: when on the ground or in flight with flaps EXTENDED, the automatic switching to High Flow is INHIBITED to ensure adequate engine power for single engine operation).
  • when operating one pack from APU (both engine BLEED air switches OFF) regulates to high flow (regardless of flap position or in air/on ground)
  • High Flow is provided from APU bleed supply as long as both engine BLEED switches are OFF. (This automatic switching to High flow (when APU is the supply) occurs for any operating pack (in AUTO) regardless of flap position or air/ground status.)

HIGH:

  • pack regulates to high flow (Don’t select HIGH for takeoff or landing as the SE performance is based upon low flow)
  • provides maximum flow rate on ground with APU BLEED air switch ON
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6
Q

PACK (light)

A

Illuminated:

  • indicates pack trip off (see below) or failure of both primary and standby pack controls
  • during master caution recall, indicates failure of either primary or standby pack control. extinguishes when master caution is reset

Below: An overheat detection will cause the pack valve to close and the PACK light will come on.

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7
Q

What systems rely on Bleed Air?

A
Air conditioning / pressurization
wing and engine thermal anti-icing
engine starting
HYD reservoirs pressurization
Water System Pessurization
Aspirated TAT probe
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8
Q

With the engine bleed air switch ON, the valve is (BLANK) activated and (BLANK) operated?

A

DC (electrical power) / pressure (pneumatically)

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9
Q

The Duct pressure indicator is powered by what electrical?

A

AC

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10
Q

The isolation valve is powered by what electrical ?

A

AC

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11
Q

Does the isolation valve open or close if either bleed air switch or air con pack is switched to off?

A

it automatically opens. Thus, in AUTO, if any engine bleed or pack switch is off (the 4 corners), the Isolation Valve enables pneumatic users to receive air from either manifold.

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12
Q

With the isolation valve switch in AUTO, both bleed air switches ON, and both air conditioning pack switches AUTO or HIGH is the isolation valve open or closed?

A

Closed

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13
Q

Is a single pack capable of maintaining max pressurization and acceptable temperatures up to the certified ceiling?

A

YUP

But note: although possible to route bleed air from one engine to operate both packs, don’t because he single engine performance is NOT based on one engine operating 2 packs. Therefore: do NOT operate more than 1 pack from 1 engine.

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14
Q

Bleed switches control…

A

respective Bleed Valves

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15
Q

Which stage provides bleed air to the pneumatic system when an engine is operating?

What happens if this stage is not sufficient?

A

5th stage bleed air.

the 9th stage modulating valve begins to open.

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16
Q

What happens when the bleed switch is turned off?

What happens when the bleed switch is turned on?

A

the bleed valve closes and isolates engine bleed air from the manifold.

Depends on if the engine is running or not. If the engine is OFF, turning on the bleed switch (and no bleed air is available from the associated engine), the valve remains closed.

If the engine is ON, turning on the bleed switch (and bleed air pressure IS available from the associated engine), the valve opens.

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17
Q

What powers the pneumatic valves?

A

DC electrical power activates the bleed valve, but the valve is opened by bleed air pressure. Therefore, this type of valve is electrically controlled but pneumatically operated.

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18
Q

Each bleed valve functions as…?

A

a pressure regulator and a shutoff valve.

*Note: Engine Bleed Valves are NOT reverse flow check valves.

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19
Q

What happens when you press the TRIP RESET button?

A

resets the MASTER CAUTION, AIR COND annunciator, resets the Protective Circuits, and restores operation of the Bleed Air Valve.

Resets a BLEED TRIP OFF, the PACK lights, or the ZONE TEMP lights.

(the related engine bleed valve opens, or related pack valve opens, or related trim air modulating valve opens. But lights remain illuminated until reset.)

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20
Q

The APU Bleed Valve is controlled by

With the APU Bleed air switch ON, the valve is (BLANK) controlled by (BLANK) power and is (BLANK) operated?

The APU bleed air directly feeds the

A

the APU Bleed Switch

electrically, DC (28V DC power), pneumatically

left pneumatic manifold

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21
Q

With the APU operating and the engine and APU bleed valves open, there is a possibility of what?

So what must be done?

A

possibility of APU bleed air back-pressuring the 9th stage modulating and shutoff valve. (This would cause the 9th stage valve to close).

The APU Bleed Valve must be closed during use of engine anti-ice to ensure that sufficient bleed air is available for cowl anti-ice.

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22
Q

In order for the APU to supply bleed air for engine start, the APU must be operating at over (BLANK) RPM?

How long must you wait to turn on the APU Bleed air?

A

95%

1 minute

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23
Q

Why do we turn off both PACK Switches before engine start?

A

so that all APU air is available to start the engines. (Both Engine Bleed switches should be on as this is the normal position of these switches. Each Bleed Valve remains closed until engine is started (there’s no pneumatic pressure present yet)

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24
Q

Why would you use the APU to operate the left pack during takeoff?

How would this be set up?

A

to increase engine performance (“bleeds off takeoff”)

Pilot manually closes the Isolation Valve, (both packs in AUTO), turns both engine Bleed Switches off, and turns the APU Bleed ON. (Note: This configuration will operate only the LEFT Pack).

After T/O, once obstacles clearance is assured:

  • Turn ON #2 engine Bleed switch (R pack operates)
  • Verify cabin pressure is stable
  • Turn OFF APU Bleed switch (wait for valve to close=left duct pressure drops to zero)
  • Turn ON #1 engine Bleed switch
  • Turn Isolation Valve switch to AUTO

(This procedure applies #1 engine bleed air to the left pack. Note: Care must be used after TO to turn OFF the APU air before turning on the #1 Bleed switch to avoid causing the DUAL BLEED light to come on at high power settings.)

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25
Q

How do we test the WING BODY OVERHEAT System?

A

press the OVHT TEST button (just to the right of the Duct Pressure gauge). This tests the wing-body overheat detector circuits.

When this button is pressed, both WING BODY OVERHEAT, MASTER CAUTION, and AIR COND annunciator lights will illuminate after a short pause. When released, both WING BODY OVERHEAT lights should extinguish.

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26
Q

Does the Pack Ram Air system provide cooling airflow for the pack heat exchangers when the aircraft is on the ground or in the air?

A

Both.

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27
Q

What do the Ram Inlet Doors do? How do they work?

A

The Ram inlet door position controls the amount of airflow that moves through the ram air system and therefore over the heat exchangers for the associated pack.

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28
Q

When are the Ram Inlet Doors fully open, and how would we know if they’re fully open?

When does the RAM DOOR FULL OPEN light illuminate?

A

When on the ground, or when inflight with flaps extended, or inflight when maximum cooling is necessary.

The RAM DOOR FULL OPEN light illuminates when they are full open, otherwise it’s extinguished.

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29
Q

When will the Ram Inlet Doors close, and how would we know?

What determines the position of the Ram Inlet Doors?

A

They begin to close after takeoff and during cruise flight.

The RAM DOOR FULL OPEN lights extinguish when the doors begin to close.

The compressor discharge temperature determines the position of the Ram Inlet Door. (The position of each Ram inlet door modulates to maintain the optimum compressor discharge temperature for the associated air cycle machine operation.)

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30
Q

What prevents slush and debris from entering the RAM AIR System?

How do they operate and how are they controlled?

A

The Deflector Doors forward of the Ram Inlet doors.

Deflector Doors are electrically operated, and they extend when on the ground

Doors are controlled by the Air/Ground Sensor.

31
Q

When will the Ram Inlet Doors be fully closed?

A

When in cruise flight with cold ambient temperatures. Note: “Full closed” still has a small opening that allows ram air to enter so that some ram air continues to pass over the heat exchangers.

Note: The cooling fan (used while on the ground and slow flight) inside the ram air duct stops once airborne).

Also note: During cruise flight, the Pack Ram Air system will automatically operate to maintain desired pack temperature if possible.

32
Q

How do you provide cooling air for the heat exchangers while on the ground or in slow flight?

How does the pilot control this?

A

The shaft of the air cycle machine compressor and turbine extends through a seal into the ram air duct. There is a fan mounted on this shaft which provides air for the heat exchangers when on the ground or in slow flight.

Note: The pilot does NOT have control of this fan operation!

33
Q

What are the 3 temperature zones?

What are the approximate temperatures of each zone?

A
Flight Deck (CONT CAB)
Supernumerary Cabin (FWD CAB)
Main Deck Cargo Compartment (AFT CAB)

COLD is 65 degrees F.
WARM is 85 degrees F.

AUTO (or center position) is approximately 70 degrees F.

34
Q

What controls the temperature of air delivered from the 2 packs?

What controls the bleed airflow to this system?

What is it’s normal position?

A

The Trim air system

A Master Trim air switch

Normal position is ON. (We do this during preflight)

35
Q

What happens when we turn on the Trim Air switch?

What does that do?

A

The trim air pressure regulator and shutoff valve is open.

It allows hot bleed air to flow to the 3 trim air modulating valves.

36
Q

What do the trim air modulating valves do?

How many are there?

A

They provide temperature control to each of the 3 zones.

There are 3 air modulating valves

37
Q

How many air supply lines to the cabin, supernumerary, and main deck cargo compartment?

A

1 line to the cabin, 1 to the supernumerary, and 2 lines to the main deck cargo compartment.

38
Q

If the Trim Air switch is selected to OFF, what controls the temperatures of the zones?

A

The left pack provides air at the temperature selected for the flight deck, the right pack provides an air temperature that is the average between the FWD and AFT Cabin Temp Selectors.

Note: Trim Air is normally ON and both packs satisfy the temperature demand of the zone requiring the most cooling; thus the air supply may be too cold for other zones. So if the CAB selector is set the lowest, the modulating valve for it is closed, but the modulating valves of the FWD cab (Supernumerary) and AFT cab (Main Deck) are open to add warm air to those zones.

39
Q

During single pack operation, when is the zone temperature controlled the same as during two pack operations?

A

When on one pack and the Trim Air is ON. (Note: the operating pack is providing the temperature of the coldest zone selection.)

40
Q

Two controllers are used to control the Trim Air modulating valves.
-The right controller provides the modulation of the __________cabin and also performs as the primary controller for the _____________.

-The left controller provides the modulation of the __________cabin and also performs as the primary controller for the _____________.

A

Supernumerary, flight deck

Main Deck Cargo compartment, flight deck

41
Q

During single pack operation with the trim air OFF, what temperature does the operating pack attempt to provide?

A

The temperature that satisfies the Average of all 3 zones.

42
Q

If any individual zone is switched to off, what happens?

What will the temperature tend to be?

A

The associated Trim Air Modulating Valve for that switch closes and the temperature setting for that zone is ignored.

The affected zone temperature will tend to be the temperature from the packs.

43
Q

What happens if all the zone selectors are switched OFF?

A

Each pack delivers a default temperature:

Left pack supplies 75 degrees F default
Right pack supplies 65 degrees F default

44
Q

How many positions on the Air Temperature Source Selector?

A

7

45
Q

What determines the output temperature from the packs?

A

the coldest zone selection of any one selector

46
Q

What makes a zone warmer or colder?

So what is it ultimately doing?

A

Turning the zone selector, which adjusts the respective trim air modulating valve as needed. (Adds heat to the pack output)

47
Q

When will the Zone Temp lights illuminate?

What will happen?

Can it be reset?

A

if there is a duct temperature overheat for a specific zone.

The associated trim air modulating valve closes!

Once the duct has cooled, yes. By pressing the TRIP RESET switch on the BLEED PANEL (follow the non-normal procedure.)

48
Q

When will the Control Cabin (CONT CAB) Zone Temp light illuminate?

A

upon recall if there is a failure of the flight deck Primary or Standby temperature control.

If BOTH the Primary and Standby temperature controls fail, the CONT CAN Zone Temp light and MASTER CAUTION lights illuminate automatically

49
Q

When will the FWD or AFT Zone Temp lights illuminate? And what has happened?

Do the temperature selectors remain operational?

A

upon recall if there is a failure of the FWD or AFT temperature control (respectively). The associated trim air modulating valve will Close!

Yes, but the forward and aft temperature selections are averaged.

50
Q

Zone temp Light illuminations during recall:

A

CONT CAB: Failure of Primary or Standby Temperature Control
FWD CAB: Failure of the associated zone temp control
AFT CAB: Failure of the associated zone temp control

51
Q

Any failure affecting the supply of trim air will cause what?

A

the temperature control system to control both packs independently. (I.e. if flight deck trim air is lost, the Left pack satisfies the temperature demand of the flight deck and the Right pack satisfies the temp demand of the FWD or AFT zones, whichever requires the most cooling. If either the supernumerary or main deck trim air is lost, or if ALL trim air is lost, the temp demands of these 2 zones will be averaged for control of the Right pack.)

52
Q

What happens if all zone controls and primary pack controls fail?

A

The standby pack controls command the packs to produce temps which will satisfy the Average temp demand of the 2 cabin zones. Note: In this case, the trim air modulating valves will close!

Additionally, the flight deck Zone Temperature Selector will have No Effect on the standby pack controls.

53
Q

What will cause the packs to trip off?

Where are these sensors located?

A

Excessive temperatures detected by the sensors will cause the pack to trip off and the associated Pack light to illuminate.

There are temp sensors in each pack, located at the compressor discharge and the turbine outlet?

54
Q

Where does the main cargo deck (FWD and AFT) get its air?

What is the normal position of the FWD and AFT Main Shutoff Valves?

When will the FWD and AFT Main Shutoff Valves close? What happens then?

How long do they take to close?

Does the closing of these valves affect air flow to the flight deck or supernumerary cabin?

A

from the mix manifold

Open, but can be closed to stop the supply of air to the cargo compartment.

When the DEPR switch on the cargo fire panel is pressed! Closing these will stop the supply of air to the cargo compartment and will gradually depressurize the aircraft! (The time varies according to altitude and position of the outflow valve.)

Several seconds.

Nope

55
Q

What is the normal position of the Mix Manifold Exhaust Shutoff Valve?

A

Closed.

56
Q

What happens when you press the DEPR(essurization) switch on the Cargo Fire Panel?

A
  • The FWD and AFT Main Shutoff Valves close
  • The Mix Manifold Exhaust Shutoff Valve opens, discharging mix manifold air below the floor and above the front spar.
  • The aircraft gradually depressurizes (depending on altitude and position of the outflow valve.)
57
Q

How many equipment cooling fans are there? What are they and how do they operate?

How many operate at a time?

What do they cool?

A

4, the Supply Fan (normal or alternate) is a Push fan that forces air into the control stand and instrument panels. The Exhaust Fan (normal and alternate) is a Pull fan and draws air through the E&E compartment

2 operate at a time

The EFIS equipment, cockpit circuit breaker panels, and the E&E compartment equipment

58
Q

What happens if the normal air supply for the supply or exhaust fans is inadequate?

Is that in the air or on the ground?

A

the associated OFF light illuminates, along with the OVERHEAD annunciator light and the MASTER CAUTION lights.

If on the ground with this airflow failure, a horn sounds in the nose gear wheel well.

59
Q

How is the OFF light activated for the supply or exhaust fans?

What should you do?

A

There is a thermal “no-airflow” detector. Normally, the fan blows air over a small heater and then over the detector. If there is a loss of cooling airflow, the small heater causes the detector to sense the lack of airflow and the OFF light comes on.

If the OFF light comes on, pilot should selection of the Alternate fan will normally cause the airflow to be restored and the OFF light will extinguish within 5 seconds.

60
Q

When on the ground (or in flight when the cabin differential pressure is low), where does the exhaust cooling fan duct air? Why?

A

ducted overboard through the open Overboard Exhaust Valve. This design allows the warm air not to heat the walls of the forward compartment when the aircraft is on the ground or low cabin differential pressure.

61
Q

When in flight and the cabin differential pressure is high, where does the exhaust cooling fan duct air? Why?

Where does this air eventually get discharged?

A

the exhaust is routed “around” (NOT into) the forward cargo compartment. The warm air around the forward cargo compartment keeps the compartment liner warm. (Note: The Overboard Exhaust Valve is closed during flight).

After flowing from the E&E compartment around the walls of the Forward Cargo compartment, air is eventually discharged through the outflow valve.

62
Q

What causes the Overboard Exhaust Valve to close?

A

The increased differential pressure in flight.

63
Q

Can the APU supply bleed air for both packs on the ground or in the air?

A

Ground: Both
Air: 1 pack only

Note: When the APU is the sole source of bleed air, the pack (or packs) automatically switch to high flow.

64
Q

Can the ground cart supply bleed air for both packs on the ground?

A

Most of them, yes

65
Q

When a pack switch is moved to AUTO, will the respective pack valve open?

A

if bleed air is available, yes.

66
Q

If the APU Bleed switch is on while on the ground, and either or both pack switch(es) in HIGH, the APU increases what?

Why would you want to do that?

A

the bleed air flow rate to the packs

Maximum cooling on the ground (when the APU is the bleed source) is achieved by placing the pack switches to HIGH.

67
Q

How does the air turbine and compressor assembly in the Pack get its power for continued operation?

A

After air passes the heat exchanger, it flows through the air cycle machine (for additional cooling), over the compressor, and then over a temperature sensor, through the secondary heat exchanger, over another temp sensor, then the Air flows over the turbine where the temperature of the air is further reduced. The energy provided by the rapid expansion of air over the turbine is used to drive the turbine and compressor assembly.

68
Q

What determines the temperature of the air flow from the pack?

A

The position of the pack temperature control valve. All the processed cold air does its thing, it is combined with hot air which has bypassed the air cycle machine by flowing through this pack temperature control valve, so the valve is really what determines the temp.

69
Q

The conditioned air (processed air mixed with air that has bypassed the air cycle machine via the pack temp control valve) flows through what before entering the mix chamber? Why?

A

the water separator (Anti-Ice Valve), to remove excess moisture (it is warmed as necessary to ensure no ice buildup)

70
Q

After conditioned air leaves the water separator, where does it go?

A

to the Mixing chamber where it mixes with air from the other pack.

71
Q

The Electronic Controllers command the operation to satisfy pack temperature discharge requirements. Which controller is Primary and Secondary?

What happens if a primary pack control fails?

What happens if a Secondary pack control fails?

Will the pack continue to operate?

A

The Left controller is primary for the Left pack, the Left ram air system, but provides standby control for the Right pack.
The Right controller is primary for the Right pack, the Right ram air system, but provides standby control for the Left pack.

If a Primary fails, the standby pack control, in conjunction with the standby pack temp control valve controls the affected pack.

Either a primary or standby control failure causes the PACK, MASTER CAUTION, and AIR COND annunciator lights to illuminate on Recall.

If Both the primary and standby pack control fail for the same pack, the PACK, MASTER CAUTION, and AIR COND annunciator lights illuminate automatically In this situation, the pack will continue to operate WITHOUT CONTROL unless it is tripped off due to excessive pack temperatures.

72
Q

When will the AUTO FAIL light illuminate (in the pressurization system)?

What will happen? What lights are illuminated?

A
  • Loss of DC power
  • controller fault
  • outflow valve control fault
  • excessive differential pressure (>8.75 psi.) if controller is not responding properly
  • Excessive rate of cabin pressure change (+- 2,000 sea level feet/minute)
  • High cabin altitude (above 15,800 feet)

With illumination of the AUTO FAIL light, the pressure control automatically transfers to the other auto controller (ALTN mode). The AUTO FAIL light will extinguish, but the ALTN light remains illuminated to indicate single channel operation.

73
Q

What is the High Altitude Landing Switch used for (N5227A)?

A

the controller brings the cabin altitude to the landing airport elevation when the descent mode is activated. upon departure from a high altitude airport, the system returns to normal operation as the cabin altitude descends through 8,500 feet.

74
Q

When does the green MANUAL Light illuminate (in the pressurization system)?

When do we use the manual control?

Where does the manual control get its electricity?

A

Whenever the pressurization mode selector is in the MAN position.

We use manual control of the cabin altitude if both the AUTO and ALTN modes are inoperative. In the MAN mode, the outflow valve position switch is used to modulate the outflow valve by monitoring the cabin altitude panel and valve position of the outflow valve position indicator.

A separate DC motor, powered by the DC standby system, drives the outflow valve at a slower rate than the automatic modes. (Outflow valve full range of motion takes up to 20 seconds).