Shared Flashcard Set

Details

747 Air Conditioning
updated 12/5/13
31
Aviation
Professional
10/23/2012

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Cards

Term
How many Pack Temperature Controllers are there?
Channels?
Definition
Two PTC's: A and B
Each PTC has three separate channels
Term
Describe the NORM, A and B positions of the Pack Controllers
Definition
NORM: primary controller selected automatically on alternate flights

A or B: selects primary controller, selects other if fails
Term
What happens if a pack temperature controller detects a fault in a pack channel?
Definition
Control of the respective pack switches to the other PTC
Term
What would happen if an overheat or a PTC fault is detected?
Definition
The respective pack valve closes, resulting in a pack shutdown
Term
How can you restore pack operation for a failed PTC?
Definition
Push the pack reset switch
Term
When does the Flight Deck Fan operate?
Definition
On the ground until first pack is on

Some aircraft - increases flow with one pack on then disables in flight
Term
What is the flight deck temperature with the Flight Deck Temperature selector in AUTO?
Definition
18°C to 29°C
Term
Which valve are you controlling when you select MAN with the Flight Deck Temperature controller?
Definition
Flight deck trim air valve
Term
What is the temperature range with the main deck and forward and aft lobe temperature selectors in AUTO?
Definition
4°C to 29°C
Term
What target temperature is set to the upper deck and crew rest zone when electrical power is initially applied to the airplane?
Definition
24°C
Term
What are the functions of the MAN position of the Lower Lobe Temp selectors?
Definition
Controls forward/aft lower lobe cargo trim air valve when LLCCAFR selector is in use

Resets forward/aft LLCC Air Supply Duct SOV if valve closed by duct overheat
Term
With the LLCCAFR selector OFF, what controls pack outlet temperature?
Definition
The flight deck, upper deck, and crew rest zone requiring the coolest temperature
Term
Explain the zone and pack configuration with the LLCCAFR selector in FWD HIGH and FWD LOW?
Definition
FWD HIGH: all of pack 3 air is sent to forward lower cargo, all packs remain in high flow during cruise

FWD LOW: 2/3 of pack 3 air is sent to forward lower cargo, pack 3 remains in high flow during cruise
Term
Explain the zone and pack configuration with the LLCCAFR selector in BOTH LOW
Definition
2/3 of pack 3 and 2 air is distributed respectively to forward and aft lower cargo, all packs remain in high flow during cruise
Term
What position of the LLCCAFR selector would result in all packs remaining in high flow during cruise?
Definition
FWD HI/AFT HI
BOTH LOW
Term
What are the functions of the Trim Air switch?
Definition
Opens master trim air valve
Enables auto and manual selection of pack controller A or B
Term
What are the functions of the Zone Reset switch?
Definition
Fault no longer exists: resets ZTC
Duct overheat no longer exists:
reopens master trim air valve or
reopens fwd/aft lower lobe cargo trim air valve
Term
Zone System FAULT light
Definition
Zone Temperature controller fault
Temperature zone duct overheat
Trim Air switch off
Master Trim Air valve failed closed
Master Trim Air valve closed and pack air continues to flow
Term
What are the 7 temperature zones?
Which zones are controlled by the Master Trim Air valve?
Definition
Master Trim Air controls:
Flight deck and upper deck
Crew rest
Forward and aft main deck

Does not control:
Forward and aft lower lobe cargo zones
Term
When is trim air unavailable to the flight deck, upper deck, crew rest, and main deck?
Definition
EICAS advisory TEMP ZONE or TRIM AIR OFF
Center section of the bleed duct is isolated
Master trim air switch if OFF
Term
When is trim air unavailable to the forward and aft lower lobe cargo compartments?
Definition
EICAS advisory TEMP ZONE (duct overheat or ZTC fault)
Center section of the bleed duct is isolated
Term
If trim air is not available, how is temperature controlled in the cabin and lower cargo compartments?
Definition
Cabin: Fight Deck Temp selector, last temperature set or 24°C

Lower cargo: Aft/Fwd Temp selectors, cargo temp at time of backup, pack outlet temp at time of backup
Term
What is the source of air for the aft cargo heat system? How is temperature regulated?
Definition
System uses air from the center bleed air duct

Temperature control and overheat/shutoff valves are operated by thermal switches
Term
What is the source of heat for the forward cargo compartment?
Definition
Heated air exhausted from the E and E compartment
(only when the equipment cooling inboard exhaust valve is open)
Term
What is the source of equipment cooling air for flight deck electrical equipment? When is it available?
Definition
With 2 or 3 packs operating, the flight deck equipment cooling valve opens and directs conditioned air to the flight deck electrical equipment
Term
When is the ground exhaust valve open on the ground?
Definition
Engines not running
Equipment Cooling Switch in NORM
Temp > 7°C
Term
When does the ground exhaust valve close for flight?
How is it manually closed?
Definition
One or more engines on each wing is operating

Positioning the Equipment Cooling selector to STBY
Term
Under what conditions would the equipment cooling system revert to closed loop mode?
Definition
LLCCAFR selector in FWD or BOTH position
Forward Lobe Temp selector < 10°C
Internal fan fails (one)
MAIN CARGO FIRE ARM switch is pushed
Term
Which valve is closed when equipment cooling is in closed loop mode?
Definition
Inboard exhaust valve
Term
When does the equipment cooling system go into override mode? Which valves open/close?
Definition
Overheat/smoke or both fans fail

Opens: override/smoke valve
Closes: inboard exhaust, inboard supply and ground exhaust valves
Term
What provides equipment cooling with the Equipment Cooling selector in OVERRIDE?
Definition
Differential pressurized air is drawn over equipment and vented through the Smoke/Override valve
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