Air Conditioning Flashcards
Each air conditioning pack is supplied pressurized and flow-regulated air by…
- engine or APU bleed.
- a Ram Air Turbine (RAT).
- cabin air compressors (CACs).
- APU bleed.
cabin air compressors (CACs).
Outside air is supplied to four electric cabin air compressors (CAC) through two dedicated inlets located in the wing to body fairings. The air is then pressurized and flow-regulated by the CACs and supplied to _____ air conditioning pack(s).
- two identical
- three identical
- four identical
- one
two identical
Normally, to maximize system efficiency, how many cabin air compressors (CACs) run when using the APU as the power source?
- One on the left side.
- Two on the right side.
- One on each side.
- All four.
One on each side.
A ground source of conditioned air may be used to supply conditioned air directly to the cabin distribution system, eliminating the need for pack operation.
- True
- False
True
If an overheat or significant pack fault is detected, the pack…
- switches to standby mode.
- continues to run until it is manually shut down.
- switches to alternate cooling.
- shuts down automatically.
shuts down automatically.
Cabin attendants can reduce outside airflow to the cabin based on…
- the number of airplane occupants.
- inside air temperature.
- outside air temperature.
- selecting the TRIM AIR on the flight deck air conditioning panel.
the number of airplane occupants.
Pack outlet temperature is controlled by the…
- temperature zone requiring the warmest air.
- trim air valve.
- temperature zone requiring the coolest air.
- pack valve controller.
temperature zone requiring the coolest air.
What is the status of CACs and Packs during a normal engine start?
- One CAC operates on each side. Both packs are commanded off.
- Both CACs operate on each side. Both packs are commanded off.
- All CACs are commanded off during the initial start sequence.
- All four CACs and both packs are fully operative during normal engine start.
All CACs are commanded off during the initial start sequence.
Which of the following occurs during Standby Cooling Mode?
- EICAS advisory message PACK MODE (L, R) is displayed.
- STBY COOLING is displayed in amber on AIR synoptic.
- Pack cooling capacity may be less than in normal mode.
- All of the above are correct.
All of the above are correct.
Which of the following statements is correct when the right pack is operating in the standby cooling mode (left pack operating normally)?
- The right pack automatically switches to high flow.
- The right pack may shut down at higher altitudes.
- The right pack cooling capacity may be less than in normal mode.
- There is no EICAS indication of either pack operating in the standby mode.
The right pack cooling capacity may be less than in normal mode.
A/An ________ source of conditioned air may be used to supply air directly to the cabin distribution system.
- APU bleed
- ground
- engine bleed
- standby
ground
What cools the large motor power distribution system located in the aft E/E equipment compartment?
- The Integrated Cooling System (ICS).
- The Power Electronics Cooling System (PECS)
- Conditioned air ducted from the passenger cabin.
- The Miscellaneous Cooling System.
The Power Electronics Cooling System (PECS)
The Power Electronics Cooling System (PECS) is a liquid cooling system used to cool the large motor power distribution system. The large motor power distribution system is located in…
- the Flight Deck equipment compartment.
- the foward E/E equipment compartment.
- the wing to body fairings.
- the aft E/E equipment compartment.
the aft E/E equipment compartment.
Choose the correct statement below regarding the Integrated Cooling System (ICS).
- ICS is a refrigerant cooling system designed to reduce heat loads on the flight deck and integrated with the forward electrical and electronic compartment cooling.
- ICS is controlled by a single ICS switch on the overhead panel that can remove system power.
- ICS is a centralized refrigeration system that provides cooling to galley carts and recirculated cabin air.
- ICS provides cooling and heat dissipation for components in the aft electrical and electronic compartment and non-essential equipment in the lower lobe area.
ICS is a centralized refrigeration system that provides cooling to galley carts and recirculated cabin air.
Identify which statement about the operation of the pressurization system description is true.
- In operation with the loss of pressurization, it is important that the flight crew close the outflow valves during descent.
- In the cruise mode, maximum cabin altitude is no more than 6000 feet.
- Two seconds after touchdown, both outflow valves open to pressurize the cabin.
- If cruise altitude is unavailable from the FMC in AUTO, the default cruise altitude is 41,000 feet.
In the cruise mode, maximum cabin altitude is no more than 6000 feet.
Which statement is correct regarding engine bleed air?
- It is only used for cabin pressure.
- It is only used for engine core and inlet cowl anti-ice.
- It is only used for wing anti-ice.
- It is only used for hydraulic reservoir pressurization.
It is only used for engine core and inlet cowl anti-ice.
On the787-9, the ALTN position of the VENTILATION switch…
- positions the FWD and AFT outflow valves toward the ten and one o’’'’clock positions respectively.
- puts both PACKS in a low flow condition until the system can be reset on the ground.
- commands all recirculation fans to operate at a higher flow rate to increase air flow.
- opens a valve allowing fresh outside air to be drawn into the air distribution system.
positions the FWD and AFT outflow valves toward the ten and one o’’'’clock positions respectively.
What controls the pack outlet temperature?
- The master cabin temperature controller.
- The temperature zone requiring the coolest temperature.
- The temperature zone requiring the warmest temperature.
- The average demand of all temperature zones.
The temperature zone requiring the coolest temperature.
Which statement about the Alternate Ventilation System is correct?
- The Alternate Ventilation System provides air flow into the forward electronics bay when both air conditioning packs are off on the ground.
- When the airplane is not pressurized normally and the ALT VENT switch is ON, air is drawn from the foward outflow valve to the flight deck.
- The ALT VENT switch is guarded to prevent selection, which could open the vent valve and depressurize the plane.
- The Alternate Ventilation System provides an alternate means of ventilating the cabin and flight deck in the event both packs are inoperative.
The Alternate Ventilation System provides an alternate means of ventilating the cabin and flight deck in the event both packs are inoperative.
The aft equipment cooling system provides cooling and ventilating air for the aft E/E equipment compartment and heating/ventilating air for the aft cargo compartment.
- True
- False
True
The aircraft is divided into how many temperature zones for air conditioning?
- 5
- 6
- 4
- 7
7
Two identical air conditioning packs are supplied pressurized air from…
- four Ram Air Fans.
- the APU bleed air.
- four CACs.
- the engine bleed air system.
four CACs.
If one Cabin Air Compressor (CACs) fails its respective air conditioning pack will shut down.
- True
- False
False
Normally, to maximize system efficiency, only one CAC on each side runs when using __________ as the power source.
- the APU
- PCA
- external air
- the right engine
the APU
For normal engine starts, how many Cabin Air Compressors (CACs) are commanded off during the initial start sequence?
- one on the right side and one on the left.
- one on the right side
- one on the left side
- all four
all four
For certain internal malfunctions, pack control automatically uses ___________ as a backup to normal mode.
- alternate cooling mode
- secondary cooling mode
- standby cooling mode
- direct cooling mode
standby cooling mode
If one pack is in standby cooling mode and the other pack is operating normally, the pack in standby cooling will shut down at lower altitudes and…
- lower outside air temperatures.
- higher outside air temperatures.
- higher humidity conditions.
- lower humidity conditions.
higher outside air temperatures.
The flight deck receives _________ conditioned outside air and the passenger cabin receives a mix of outside air and recirculated air.
- 100%
- 90%
- 75%
- 50%
100%
A passenger compartment dehumidification system operates automatically when…
- the upper RECIRC FAN is ON.
- both RECIRC FANs are on.
- FWD EQUIP COOLING is ON.
- electrical power is available.
electrical power is available.
Turning the recirculation fans off…
- results in increased airflow.
- will increase the amount of fresh air to the passenger cabin.
- results in a decreased airflow to the passenger cabin.
- will result in an overheat condition in the passenger cabin.
results in a decreased airflow to the passenger cabin.
Recirculation fans must remain ON during hot weather operations unless a non-normal checklist directs to select them off.
- True
- False
True
On both the 787-8 and 787-9, the Alternate Ventilation System (AVS) provides an alternate means of ventilating the cabin and flight deck in the event both packs are inoperative.
- True
- False
True
Flight crew foot heaters are available…
- on the ground and in-flight.
- only with electrical power supplied by both engines.
- only with the APU providing electrical power.
- in-flight only.
on the ground and in-flight.
The humidification system operates automatically during cruise when the HUMID switch is on and is automatically switched off approximately 1-1.5 hours prior to touch down.
- True
- False
True
The aft cargo compartment is heated but the compartment temperature is uncontrolled.
- True
- False
True
Which cargo compartment(s) is/are capable of carrying live animals?
- AFT and BULK
- FWD and AFT
- FWD and BULK
- Only the FWD
FWD and BULK
Bulk cargo compartment ventilation and heat is provided from cabin air passing through a supply fan and…
- ventilation air from the cabin.
- air from the right CAC.
- in-line electric heater.
- shoulder and foot heaters.
in-line electric heater.
Both FWD and AFT equipment cooling systems use a primary and backup supply fan. If the primary fan fails…
- the equipment cooling system will shutdown.
- the backup supply fan will operate if the FWD and AFT EQUIP COOLING switches are cycled OFF then ON.
- the backup supply fan will operate automatically.
- both flow sensors will fail.
the backup supply fan will operate automatically.
If the EICAS message PACK (L, R) is displayed, an attempt to restore pack operation may be made by pressing the AIR COND RESET switch.
- True
- False
True
Which of the following is true concerning pack operation in the “Standby Cooling” mode?
- For certain internal malfunctions, pack control automatically uses standby cooling mode as a backup to normal mode.
- The pack in standby cooling mode shuts down at lower altitudes and higher outside air temperatures.
- Pack cooling capacity may be less than in normal mode and may result in warm flight deck or cabin temperatures at lower altitude.
- All of the above.
All of the above.
If the flight deck or cabin temperature selector is unavailable to the pack temperature controller, the pack temperature is regulated to…
- keep pack outlet temperature within 20 degrees of the normal operating range.
- achieve either the last temperature set or an average cabin temperature of 75°F.
- automatically shut down.
- modulate to keep pack outlet temperature between 60°F and 80°F.
achieve either the last temperature set or an average cabin temperature of 75°F.
The cabin de-humidification system in the passenger compartment uses _______ to remove moisture from the compartment.
- two de-humidifiers
- two auxiliary fans
- two moisture separators
- two zonal dryers
two zonal dryers
The Alternate Ventilation System (AVS), on the 787-8, consists of a flight deck switch and a dedicated flush inlet valve and duct that delivers outside air flow downstream of the left pack outlet.
- True
- False
True
On the 787-8, the Miscellaneous Equipment Cooling System operation is fully automatic and powered on whenever the airplane is powered.
- True
- False
True
When is APU bleed air used?
- There is no APU bleed air.
- In flight only, if required.
- For engine starting on the ground.
- During ground operations only.
There is no APU bleed air.
On the ground with the forward equipment cooling system inoperative…
- The EICAS advisory message EQUIP COOLING FWD is displayed.
- The ground crew call horn will sound in the wheel well.
- Both 1 and 2 are correct
- None of the above.
Both 1 and 2 are correct
The Power Electronics Cooling System (PECS) consists of two independent cooling loops. Each loop has a single pump package which contains…
- one cooling pump.
- one liquid storage reservoir.
- one large motor controller.
- two fully redundant pumps.
two fully redundant pumps.
The Miscellaneous Equipment Cooling System (787-8) is fully automatic and is powered when…
- the IFE switch s OFF.
- both RECIRC FAN switches are in the OFF position.
- the aircraft is powered.
- when AFT EXT PWR switch is selected ON.
the aircraft is powered.
Two outflow valves regulate the discharge of cabin air. Cabin altitude and full ventilation rates…
- can be maintained by either valve.
- will limit the cabin altitude to 9,000 ft.
- are controled by the Cabin Pressure Control System in the MANUAL mode only.
- will cause the cabin pressure relief valves to open.
can be maintained by either valve.
The pressurization system uses data from the ________ to calculate a cabin pressurization schedule.
- FMC
- GPS
- IRU
- TCP
FMC
If cruise altitude is unavailable from the FMC in AUTO, the default cruise altitude is 43,000 feet.
- True
- False
True
If landing altitude is unavailable from the FMC, and not set in MAN, the EICAS message LANDING ALTITUDE is displayed and the cabin altitude controller assumes a landing altitude of…
- 2,000 ft.
- 6,000 ft.
- 1,000 ft.
- sea level.
2,000 ft.
If a depressurization event occurs, the outflow valves close to preserve cabin pressure. It is important that the flight crew __________ during the descent.
- not attempt to manually close the outflow valves.
- manually opens the outflow valves.
- switches to MANUAL pressurization.
- switches to the automatic mode.
not attempt to manually close the outflow valves.
If the LANDING ALTITUDE selector is pulled out to the detent, pressurization system indications will…
- be removed from EICAS.
- be displayed on EICAS.
- be displayed on the CDU scratch pad.
- will not be available to be viewed by the flight crew.
be displayed on EICAS.
The engine anti-ice valve will close automatically for which of the following conditions?
- When a bleed air leak is detected.
- During start.
- When an engine fire switch is pulled.
- All answers are correct.
All answers are correct.
What are the uses of engine bleed air?
- Potable water tank pressurization.
- Ice Crystal Anti-Ice functions.
- Wing and stabilizer anti-icing.
- Engine core and inlet cowl.
Engine core and inlet cowl.
When a pack overheat is detected, the pack…
- will switch to standby mode.
- flow rate is modulated to keep the pack outlet temperature low.
- will automatically switches pack controllers.
- will automatically shut down.
will automatically shut down.
The Air System supplies ventilation for the passenger cabin:
- galleys.
- lavatories.
- overhead crew rest compartments.
- All of the above.
All of the above.
How does the automatic pressurization system keep “pressure bumps” from occurring during takeoff?
- After liftoff, the system supplies a small positive pressure for smooth cabin altitude transition.
- The system supplies a small positive pressurization prior to rotation.
- Positive pressure relief valves go full open.
- Negative pressure relief valves transition to the fully closed position.
The system supplies a small positive pressurization prior to rotation.
What is the PECS normal service level?
- 1.20 or above
- 0.75
- 1.00
- 1.10 minimum
1.00
The Power Electronics Cooling System (PECS) requires a cool-down period following pack and hydraulic EMP shutdown to dissipate residual heat from the liquid cooled LRU’s.
- True
- False
True
Airflow to the packs is controlled by regulating the cabin air compressors (CACs). Which of the following are correct?
- CAC output is increased automatically during high demand periods to compensate for a failed pack.
- CAC output is selectable by the pilot.
- CAC output is limited during electrical load shed conditions to ensure sufficient electrical power is available to other critical systems.
- Answers 1 and 3 are both correct.
Answers 1 and 3 are both correct.
With APU as the sole source of electrical power on the ground and both pack switches in AUTO, how many Cabin Air Compressors (CACs) are normally operating?
- 4
- 1
- 2
- 3
2
On the ground during hot weather operations, how should the air conditioning panel be set up?
- Upper recirculation fan ON.
- Lower recirculation fan ON.
- Both recirculation fans ON.
- Upper recirculation fan ON, lower fan OFF.
Both recirculation fans ON.
In-flight you get the PACK R EICAS advisory message and the right air conditioning pack OFF light illuminates. What condition would cause the pack to shutdown automatically?
- Low CAC airflow.
- The CAC inlet blocker door is not in the proper position.
- RAM Fan failure.
- An overheat or other significant pack fault.
An overheat or other significant pack fault.
If your cruise altitude from KDFW to KORD is FL410 when this indication appears, do not attempt an air conditioning reset at or above:
- 25,000 ft.
- there is no need to descend; the remaining pack will hold cabin altitude.
- the FMC OPT cruise altitude.
- 34,000 ft.
34,000 ft.
In-flight the crew is allowed to reset a PACK overheat condition after waiting 2 minutes. If unable to reset this condition then:
- Turn the right pack switch OFF.
- Single pack operations will maintain normal cabin altitude at all altitudes.
- Descend to a lower altitude to maintain normal pressurization.
- Leave the PACK switch in AUTO for the rest of the flight.
Leave the PACK switch in AUTO for the rest of the flight.
While parked at the gate, maintenance connects you to the ground source of conditioned air. To properly configure the aircraft, you should…
- select both Pack Switches to AUTO.
- select both RECIRC FAN switches to ON.
- turn the lower RECIRC FAN and both PACKS OFF.
- select Alternate Ventilation switch to ALTN to allow maximum efficiency.
turn the lower RECIRC FAN and both PACKS OFF.
On a hot summer night at the gate, the ground conditioned air is not sufficient to cool the cabin. In this case you should…
- start the APU to operate the CACs.
- select the ventilation switch to ALTN to improve air flow.
- select full COLD on the flight deck and cabin temperature selectors.
- connect an aft PCA cart also.
start the APU to operate the CACs.
During a normal engine start sequence, with both left and right air conditioning packs in AUTO, all Cabin Air Compressors (CACs) are commanded off. Packs will not restart until…
- the red EGT start limit line is removed.
- two minutes after the engine start sequence is initiated and the engine is running.
- immediately after the second engine is running, if both engines are started together and the two minute limit is met.
- both 2 and 3 are correct.
both 2 and 3 are correct.
The above display indicates that… (Images show: AMBER TRIM AIR R, R TRIM AIR FAULT)
- the right zone supply duct has experienced an over temperature or overpressure.
- the left zone supply duct has overheated.
- the right trim air valve is closed.
- the right zone trim air has load shed.
the right trim air valve is closed.
With the above indication displayed, flight deck temperature is maintained… (Images show: AMBER EICAS “TRIM AIR R”, R TRIM AIR FAULT)
- between 65° and 85° F.
- at an undetermined temperature.
- at an average temperature.
- below 65° F.
between 65° and 85° F.
With the above indications displayed, cabin temperature controllers will… (Images show: AMBER EICAS “TRIM AIR R”, R TRIM AIR FAULT)
- maintain a temperature between 60° and 90° F.
- command a full cold position.
- be unable to control the cabin temperature.
- attempt to maintain all zones at the average target temperature.
attempt to maintain all zones at the average target temperature.
This EICAS display indicates that….
- forward equipment cooling is in the Override Mode.
- cooling air exits through the override valve to an overboard venturi.
- cabin differential pressure draws air through the flight deck panels for equipment cooling.
- All of the above are correct.
All of the above are correct.
With the forward equipment cooling in the override mode,…
- cooling airflow decreases as the airplane descends.
- AFT cargo heat is inoperative.
- FWD outflow valve operates in manual mode.
- cabin altitude will slowly rise.
cooling airflow decreases as the airplane descends.
The FWD EQUIP COOLING switch in OVRD is used to…
- aid in manual pressurization.
- aids smoke evacuation from the flight deck in flight.
- provide extra ventilation to cabin.
- provide increase ventilation in aft cargo compartment.
aids smoke evacuation from the flight deck in flight.
This display on the 787-8, indicates.… (IMAGE SHOWS: AFT outflow valve is amber)
- that landing altitude must be manually set.
- that the aft outflow valve not in the commanded position.
- that the aft outflow valve is being controlled manually.
- that the aft outflow valve has failed in position.
that the aft outflow valve is being controlled manually.
If the outflow valve position is not available on EICAS, holding the respective OUTFLOW VALVE MANUAL switch in the desired position for _______ moves the valve from full open or closed to the selected position.
- 15 seconds
- 60 seconds
- 45 seconds
- 30 seconds
30 seconds
With the [] OUTFLOW VALVE AFT advisory message, the QRH will:
- require the use of manual pressurization.
- limit the airplane altitude limited to 30,000 feet.
- require the AFT outflow valve to be opened descending through 10,000 feet.
- require the AFT outflow valve to be manually positioned fully closed.
require the AFT outflow valve to be manually positioned fully closed.
The EICAS message LANDING ALTITUDE is displayed when…
- a dual FMC failure occurs.
- the FMC does not supply a landing altitude.
- the landing altitude selector is pulled.
- both 2 and 3 are correct.
both 2 and 3 are correct.
Pulling the LDG ALT selector is directed when…
- landing at an airport greater than 6000 feet elevation.
- running the LANDING ALTITUDE non-normal checklist.
- experiencing a complete loss of pressurization.
- either outflow valve fails to function.
running the LANDING ALTITUDE non-normal checklist
Pulling the LDG ALT selector out removes the FMC landing altitude and displays pressurization system indications (including selected landing altitude) on the…
- pressurization synoptic.
- EICAS display.
- air synoptic.
- auxiliary display.
EICAS display.
Cruising at FL390 with the pressurization panel set in AUTO, a depressurization event occurs. While the airplane is descending and cabin altitude is increasing, the outflow valves will…
- remain closed until the airplane reaches 15,000’ or descends below the cabin altitude limit.
- close immediately and remain closed for the balance of the flight.
- open immediately and remain open for the remainder of the flight.
- remain open until the airplane reaches 15,000’.
remain closed until the airplane reaches 15,000’ or descends below the cabin altitude limit.
There is/are ________mode(s) of operation for the Cabin Pressure Control System (CPCS), ___________________________________.
- one, automatic mode only.
- four, automatic, manual, ALTN and Positive Pressure.
- three, climb, cruise and descent modes.
- two, automatic and non-automatic.
three, climb, cruise and descent modes.
If cruise altitude is unavailable from the FMC in AUTO, the default cruise altitude is…
- 40,000 feet.
- the maximum service ceiling of the airplane.
- 41,000 feet.
- 43,000 feet.
43,000 feet.
The Alternate Ventilation System (AVS) provides fresh outside air during:
- pressurized flights.
- un-pressurized flights.
- either pressurized or un-pressurized flights.
- at low altitudes only.
un-pressurized flights.
On the 787-9, what will the alternate ventilation system provide?
- An alternate means of ventilating the flight deck only.
- An alternate means of ventilating the cabin only.
- Cooling for the PECS and the aft galley MCUs.
- Fresh outside air to be drawn into the air distribution system.
Fresh outside air to be drawn into the air distribution system.
On the 787-8, when the alternate ventilation switch is pressed and the amber ALTN light illuminates, how does the cabin and flight deck get ventilated?
- An alternate ventilation fan draws air from the cargo compartment to the cabin and flight deck.
- An alternate ventilation valve directs air from the equipment cooling system to the cabin and flight deck.
- A dedicated flush inlet valve and duct deliver air downstream of the left pack outlet into the air distribution system.
- Positions the FWD and AFT outflow valves toward the ten and one o’‘clock positions.
A dedicated flush inlet valve and duct deliver air downstream of the left pack outlet into the air distribution system.
