777 Air Systems Flashcards
What. is the air source for the packs?
- Engines, APU, high pressure ground air.
How.many air conditioning pack controllers are there?
- Two.
Following a pack shut down, how is the pack reset?
- Push the AIR CONDITIONING RESET switch.
Which pack supplies 100% fresh conditioned air to the flight deck?
- The left pack.
Why is the conditioned air in the flight deck maintained at a higher pressure than the cabin?
- To prevent cabin smoke from entering the flight deck.
What is the purpose of the Recirculation Fans?
- Assists the packs to maintain a constant ventilation rate through the cabin.
In standby cooling mode, which messages are displayed on:
a. EICAS.
b. Air synoptic.
- a. PACK MODE (L/R) – Advisory
b. STBY COOLING (amber).
Under what conditions will packs operate continuously in Standby Cooling mode regardless of altitude and temperature?
- Both packs are in standby cooling, or one pack is inoperative with the other in standby cooling.
What determines the pack outlet temperature?
- The zone requiring the coolest temperature.
What is the source of Trim Air?
- Engine bleed air.
Over what range of temperature can the cabin crew adjust the cabin zones about the reference you set?
- Plus/minus 6 degrees (within the range of 18 to 29C).
Are all zones supplied with trim air?
Yes
What temperature is maintained in all zones if a trim air supply is lost?
- An average target temperature.
- Which air conditioning panel switches remain operable following a dual temperature controller failure?
- The pack switches.
- Are the shoulder and foot heaters available on the ground?
No
- Where are the controls for the Aft and Bulk Cargo heat?
- Overhead Maintenance Panel
- What is the source of air for the Aft and Bulk Cargo heating?
- Bleed air.
- The failure of which fans cause Aft and Bulk Cargo heat to fail?
- The lavatory/galley vent fans.
- How is the temperature of the forward cargo heating controlled?
- By forward equipment ventilation air being discharged into the forward cargo compartment.
- With HIGH selected for the bulk cargo heat, how is air flow increased?
- The bulk ventilation fan is turned ON.
- When selected, how are Aft and Bulk Cargo compartment temperatures controlled?
- Control valves are opened and closed by temperature sensors.
- What moves the air over the aft equipment?
Aft galley/lavatory ventilation fan.
- Where is aft cooling air exhausted?
Through aft outflow valve.
- With the equipment cooling switch at AUTO during normal operations: a. From where is the forward equipment cooling air drawn?
b. What moves the air through the system?
c. Where is forward equipment ventilation air exhausted?
a. The cabin
b. One of two supply fans.
c. Through the forward outflow valve or into the forward cargo hold for
heating.
- How many supply fans are there in the forward cooling system?
Two, a primary and a back-up.
- How is forward equipment cooling maintained in OVRD mode?
- Smoke/override valve opens and cabin pressure differential causes reverse flow of air.
- How many outflow valves are there?
- Two; forward and aft.
- When in the automatic pressurisation mode, list the data inputs used to calculate pressurisation schedule?
- Ambient pressure from ADIRS and flight plan data from the FMC.
- At what rate will the cabin climb?
- On a schedule related to the aircraft climb rate and flight plan cruise altitude.
- What will be the cabin altitude at maximum certified operating altitude?
- 8,000ft.
- From where is the landing altitude barometric reference obtained?
- Captain’s altimeter setting.
- What will the cabin altitude be just before touchdown?
- Cabin altitude decrease to slightly below planned landing altitude.
- What happens to the outflow valves at touchdown?
- Both valves open to depressurise the cabin.
- How is cabin altitude controlled for:
a. Takeoff from airports above 8000ft? b. Landing at airports above 8000ft?
- a. The cabin descends to the target altitude during climb
b. The cabin climbs to 8000 ft and before arrival climbs to destination
elevation
- What is the indication on the EICAS display that an outflow valve is under manual control?
The letter M (amber) is displayed next to the Outflow Valve Position indicators.
- What are the three air supply sources for bleed air?
- Engines, APU, Ground air.
- Once an engine bleed switch is armed, how is the bleed valve actuated?
- By pneumatic pressure.
How is pneumatic duct pressure maintained at:
a. low engine thrust? b. high engine thrust?
- a. High stage bleed air b. Low stage bleed air
- In flight, up to what altitude is the APU bleed air available?
- 22,000 feet approx.
- During normal operation what is the position of the isolation valves?
- Centre closed, Left & Right open.
- What happens if a duct leak is detected?
- The system automatically isolates the leak.
- Following a BLEED LEAK EICAS message and automatic isolation, which advisory message will confirm isolation?
- BLEED LOSS _____.
- On which displays are pneumatic duct pressures displayed?
- At the bottom of the primary EICAS screen; air synoptic; at the top of the secondary engine display before engine start if the fire switch is not pulled.
- What will cause an engine bleed valve to close and illuminate the amber OFF light in the bleed switch?
- Protective bleed shut down or duct leak; engine not running; engine fire switch pulled out; or switch selected OFF.
