Term
How many Pack Temperature Controllers are there?
Channels? |
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Definition
Two PTC's: A and B
Each PTC has three separate channels |
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Term
| Describe the NORM, A and B positions of the Pack Controllers |
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Definition
NORM: primary controller selected automatically on alternate flights
A or B: selects primary controller, selects other if fails |
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Term
| What happens if a pack temperature controller detects a fault in a pack channel? |
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Definition
| Control of the respective pack switches to the other PTC |
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Term
| What would happen if an overheat or a PTC fault is detected? |
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Definition
| The respective pack valve closes, resulting in a pack shutdown |
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Term
| How can you restore pack operation for a failed PTC? |
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Definition
| Push the pack reset switch |
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Term
| When does the Flight Deck Fan operate? |
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Definition
On the ground until first pack is on
Some aircraft - increases flow with one pack on then disables in flight |
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Term
| What is the flight deck temperature with the Flight Deck Temperature selector in AUTO? |
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Definition
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Term
| Which valve are you controlling when you select MAN with the Flight Deck Temperature controller? |
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Definition
| Flight deck trim air valve |
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Term
| What is the temperature range with the main deck and forward and aft lobe temperature selectors in AUTO? |
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Definition
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Term
| What target temperature is set to the upper deck and crew rest zone when electrical power is initially applied to the airplane? |
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Definition
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Term
| What are the functions of the MAN position of the Lower Lobe Temp selectors? |
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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 |
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Term
| With the LLCCAFR selector OFF, what controls pack outlet temperature? |
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Definition
| The flight deck, upper deck, and crew rest zone requiring the coolest temperature |
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Term
| Explain the zone and pack configuration with the LLCCAFR selector in FWD HIGH and FWD LOW? |
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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 |
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Term
| Explain the zone and pack configuration with the LLCCAFR selector in BOTH LOW |
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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 |
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Term
| What position of the LLCCAFR selector would result in all packs remaining in high flow during cruise? |
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Definition
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Term
| What are the functions of the Trim Air switch? |
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Definition
Opens master trim air valve
Enables auto and manual selection of pack controller A or B |
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Term
| What are the functions of the Zone Reset switch? |
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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 |
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Term
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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 |
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Term
What are the 7 temperature zones?
Which zones are controlled by the Master Trim Air valve? |
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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 |
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Term
| When is trim air unavailable to the flight deck, upper deck, crew rest, and main deck? |
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Definition
EICAS advisory TEMP ZONE or TRIM AIR OFF
Center section of the bleed duct is isolated
Master trim air switch if OFF |
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Term
| When is trim air unavailable to the forward and aft lower lobe cargo compartments? |
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Definition
EICAS advisory TEMP ZONE (duct overheat or ZTC fault)
Center section of the bleed duct is isolated |
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Term
| If trim air is not available, how is temperature controlled in the cabin and lower cargo compartments? |
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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 |
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Term
| What is the source of air for the aft cargo heat system? How is temperature regulated? |
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Definition
System uses air from the center bleed air duct
Temperature control and overheat/shutoff valves are operated by thermal switches |
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Term
| What is the source of heat for the forward cargo compartment? |
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Definition
Heated air exhausted from the E and E compartment
(only when the equipment cooling inboard exhaust valve is open) |
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Term
| What is the source of equipment cooling air for flight deck electrical equipment? When is it available? |
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Definition
| With 2 or 3 packs operating, the flight deck equipment cooling valve opens and directs conditioned air to the flight deck electrical equipment |
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Term
| When is the ground exhaust valve open on the ground? |
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Definition
Engines not running
Equipment Cooling Switch in NORM
Temp > 7°C |
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Term
When does the ground exhaust valve close for flight?
How is it manually closed? |
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Definition
One or more engines on each wing is operating
Positioning the Equipment Cooling selector to STBY |
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Term
| Under what conditions would the equipment cooling system revert to closed loop mode? |
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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 |
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Term
| Which valve is closed when equipment cooling is in closed loop mode? |
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Definition
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Term
| When does the equipment cooling system go into override mode? Which valves open/close? |
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Definition
Overheat/smoke or both fans fail
Opens: override/smoke valve
Closes: inboard exhaust, inboard supply and ground exhaust valves |
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Term
| What provides equipment cooling with the Equipment Cooling selector in OVERRIDE? |
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Definition
| Differential pressurized air is drawn over equipment and vented through the Smoke/Override valve |
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