Air Systems Flashcards
How many packs are on the aircraft?
3
What is the function of the packs?
Deliver conditioned bleed air at controlled temps the aircraft.
What are the 7 temperature zones?
- Flight Deck
- Crew Rest
- Upper Deck
- FWD Main Cargo
- AFT Main Cargo
- FWD Lower Lobe
- AFT Lower Lobe
How many packs can the APU power on the ground?
How many packs can the APU power in the air?
3x Packs on the ground
1x Pack in the air <= 15,000’
What is the flight deck temperature range with the Flight Deck (FLT)
temperature Selector in AUTO?
65F to 85F (18C to 29C)
What valve are you controlling when you select MAN with the flight deck
temperature controller?
Flight deck trim air valve
What does the Zone System (SYS) Fault Light indicate?
• Temperature zone duct overheat or zone temperature controller fault has
occurred.
• Master trim air valve failed closed
• Trim air switch off
• Master trim air valve closed and pack air continues to flow.
What is the temperature range with the main deck and forward and aft lobe
temperature selectors in AUTO?
40F to 85F (4C to 29C)
Under what conditions would trim air be unavailable to the flight deck, upper
deck, crew rest, and main deck?
- EICAS advisory TEMP ZONE is displayed.
- Center section of the bleed duct is isolated.
- EICAS Advisory message TRIM AIR OFF is displayed.
- The Master Trim Air switch is OFF.
If trim air is not available to the flight deck, upper deck, crew rest, and main
deck distribution system, how is temperature controlled in the cabin?
• Backup modes control temperature
• If the flight deck temp selector setting is available to the PTC, pack outlet
temperature of all packs is regulated to an average temp between 65F
and 85F, as set by the Flt Deck Temp selector, or
• If unavailable to the PTC, the last temperature set, or
• If last temp unavailable to the PTC, then 75F (24C)
What target temperature is set to the upper deck and crew rest zone when
electrical power is initially applied to the airplane?
75F (24C)
How many pack temperature controllers (PTC) are provided?
Two – A and B
How many separate channels are provided in the PTCs?
Each PTC has three separate channels, one for each pack.
What happens if a pack temperature controller (PTC) detects a fault in a pack
channel?
Control of the respective pack switches to the other PTC.
How can you restore pack operation for a failed PTC?
Push the Pack Reset Switch.
What would happen if a fault or an overheat of the PTC is detected?
The respective pack valve closes, resulting in a pack shutdown.
Equipment cooling provides cooling air for what compartment/systems?
- Flight deck equipment
* Electrical and equipment racks (E & E)
When is warm exhaust air ducted overboard through the ground exhaust valve?
- Engines not operating
- Equipment cooling selector in NORM
- Ambient temperature moderate or high
When does the equipment cooling system configure for flight?
One or more engines on each wing is operating.
How can you manually configure the equipment cooling system for flight?
Positioning the Equipment Cooling Selector to STBY.
Which valve is closed when equipment cooling is in closed loop mode?
Inboard exhaust valve
What is the source of equipment cooling air for the flight deck electrical equipment?
With two or three packs operating, the flight deck equipment cooling
source valve directs conditioned air into the flight deck electrical
equipment.
Describe the operation of the equipment cooling system with the Equipment
Cooling Selector in OVRD.
• Provides equipment cooling in flight if internal fans are inoperative.
• Internal fans are not powered.
• Smoke/override valve opens.
• All other valves closed, no air flow to forward cargo.
• Cabin differential pressure draws air from the panels area on the flight
deck, through the equipment cooling ducts to the E&E, to create a
reverse flow of air across the equipment, then through the supply duct,
then overboard.
Under what conditions would the equipment cooling system revert to closed
loop mode?
• LLCCAFR Selector in FWD LOW, BOTH LOW, FWD HIGH, with a
forward lobe temp selector set lower than 10C (50F).
• If a single internal fan fails.
• When the MAIN CARGO FIRE ARM switch is pushed.
