Air Conditioning & Pressurization Flashcards
Can flight deck fan operate in flight?
Fan disabled in Flight.
FCOM 1 21.10.2
How is the flight deck temperature adjusted with flight deck temperature selector in MAN?
- Spring loaded to 6 o’clock position.
- C (cool): valve moves towards closed to supply cooler air.
- W (warm): valve moves towards open to supply warmer air.
FCOM 1 21.10.2
How does the alternate vent operate?
With aircraft depressurised, opens Alt Vent Valve.
- Outside air supplied to flight deck.
- When switch is pushed on, valve moves to open position.
- 29 seconds after switch is pushed on, valve can be repositioned with the Alt Vent Selector.
FCOM 1 21.10.4
Which zones are temperature range limited to 18-29?
Flight Deck, Upper Deck, Crew Rest.
FCOM 1 21.10.2
What is the function of the PACK RESET switch?
- Resets pack fault detection system.
- Restarts Packs after automatic shutdown if fault no longer exists.
- Reopens master trim air valves if duct overheat no longer exists.
FCOM 1 21.10.8
What is the purpose of and how many IASC are installed?
Controls pack output temperature to ensure minimum temperature for flight deck and some bleed air function (only 2)
FCOM 1 21.20.1
Describe the Air conditioning pack flow rates regulations.
3 flow rates: economy (0.06%), Normal (0.3%) and high.
FCOM 1 21.20.1
When will pack output automatically operate in ECONOMY MODE?
In cruise flight at or above FL250, the configuration for economy flow is:
- All packs operating, and
- The high pack flow switch OFF, and
- Both forward and Aft main deck temperature selector is OFF, and both forward and aft lower lobe temperature selectors in OFF
FCOM 1 21.20.1
How can all packs be configured to high flow in cruise?
Push “Pack high flow” switch ON
FCOM 1 21.20.2
What are the indications when a pack is operating in a “Standby cooling mode”?
EICAS advisory message “PACK MODE” displayed.
- Pack cooling capacity may be less than normal.
- Warmer flight deck and cabin temperatures may occur at lower altitudes.
FCOM 21.20.3
Describe purpose of the Recirculation and the Zones excluded.
Assists the packs to maintain a constant ventilation rate to the main deck and lower lobe cargo zones. The fans draw cabin air through filters, then reintroduce air into the conditioned air distribution system.
FCOM 1 21.20.3
Describe the packs airflow distribution
Flight Deck-Packs 1 & 3
Main Deck-All Packs
Forward Lower Lobe-Pack 3
Aft Lower Lobe-Pack 2
How does aircond packs determine the lowest pack output temperature?
Lowest temperature on selector for Cargo
FCOM 1 21.20.6
How many degrees can the supernumerary modify the Crew Rest Area Zone temperatures?
+/- 6 degrees C from 18-29 degrees.
FCOM 1 21.20.7
What is “BACKUP MODE” in air conditioning system?
If a system fault or overheat occurs in a temperature zone, the respective master trim air valve closes and a backup mode controls cabin temperature.
FCOM 1 21.20.7
How does the lack temperature respond when trim air is not available?
Loss of LH Trim air: Pack supplies the average temp of the flight deck and upper deck zones set by the flight deck temperature selector.
Loss of RH Trim air: Backup Mode (Regulated to maintain lowest temperature set by the respective temperature selector in the cargo zones, but not lower than the target temperature set for flight deck)
FCOM 1 21.20.7
How can zone temperature control be reset after an overheat condition?
Pushing pack reset switch.
FCOM 1 21.20.7
Describe the purpose of the trim air isolation valve.
Allows either left or right trim air to be supplied to all temperature zones. (Normally closed).
FCOM 21.20.6
Where does the equipment cooling air discharge to?
Forward Cargo Compartment
FCOM 21.20.9
How is the lower aft cargo compartment heated?
Bleed air from the Centre section of the bleed air duct. A thermal switch in the compartment opens and closed the lower lobe aft cargo heat temperature control valve. (Cool Open, Warm Close)
FCOM 1 21.20.6
When is Aft lower lobe cargo heating available?
Aft lower lobe temperature selector must be in OFF.
Low (4 degrees) High (10 degrees)
FCOM 1 21.20.7
When will the system configure to closed loop operation?
- Forward lower lobe temperature set to below 10 degrees.
- Single infernal Fan fail.
- In closes loop mode, onboard exhaust valve is closed.
FCOM 1 21.20.9
When does the equipment cooling system configure for flight?
One or more engine on each wing operating.
FCOM 1 21.20.9
In flight, what happens to the equipment cooling system when the forward lower lobe temperature selection is set below 10 degrees?
Onboard exhaust valve closed and air recirculated in a closed loop.
FCOM 1 21.20.9
How can the equipment cooling system be manually configured for flight?
Positioning Equipment cooling selector to STBY.
FCOM 1 21.20.9
Which valve opens when Equipment cooling OVRD is selected?
Smoke/over ride valves open.
FCOM 1 21.20.9
What regulates the overboard discharge of conditioned cabin air and why?
Cabin pressurisation through outflow valves.
FCOM 1 21.30.1
How many outflow valves are required for full automatic operation?
One. Two valves are installed and either are capable of maintaining full automatic operation.
FCOM 1 21.30.1
What condition will cause pack #2 to shut down?
When pressure relief valve is Open.
FCOM 1 21.30.2
When will the cabin altitude controllers assume aircraft cruise altitude of 39,000 feet?
When cruise altitude is unavailable from the FMC in AUTO
FCOM 1 21.30.1
What is the highest cabin altitude in cruise with cabin altitude control in AUTO?
8000 Feet
FCOM 1 21.30.1
What type of cabin relief valves are located at the cargo doors?
6 negative pressure relief valves.
FCOM 1 21.30.2
During descent, why does the cabin altitude decrease to slightly below the FMC landing altitude?
Assured small positive pressurisation at touchdown
FCOM 1 21.30.2
