Air Systems Flashcards
What does the Air Conditioning system use to control temperature?
The 3 packs
What are the temperature zones?
Flight Deck
Upper Deck
Crew Rest
Forward and aft Main Deck
Forward and aft Lobe cargo
What is the route of air from the engine to the cabin?
Engine > Packs > Distribution system> Cabin
On the ground with the packs off, how can we air condition the cabin?
With LP air connected to the distribution system
What can power the packs?
Engines
APU
HP ground air
What is the PTC?
Pack Temperature Controller
On the Temperature display what are the temperature indications?
Magenta - Target
Actual - White
What is the function of the trim air system?
Can add bleed air to any zone so that each zone may be independently controlled
What is the advantage of normal flow over high flow?
Improved fuel efficiency
How many temperature zones are on the Freighter B747 Aircraft?
7
T/F: As a precaution both Pack Temperature Controllers are active at the same time.
False
The three identical packs are normally supplied bleed air from the __________.
Engines
The master temperature for the Cabin can be adjusted between ________ and ________.
18C -29C
65F - 85F
What is the route of airflow inside the pack?
Through the 2 heat exchangers, the compressor, turbine, and water separator.
What happens when a pack selector is set to OFF
-Resets the pack fault protection system
-Extinguishes the SYS FAULT light (if it was illuminated due to a fault in the associated pack).
-EICAS memo message PACK 1,2, or 3 OFF displays
-OFF will also be displayed on the ECS synoptic display
What will happen if a fault is detected on a PTC that a pack is using?
The associated pack will automatically switch to the other PTC, with trim air ON
What will happen if a fault is detected on a PTC that a pack is using, with trim air OFF?
The associated pack will select PTC A in manual or auto and B can only be used if A fails, with trim air OFF
What determines the flow rate when the HI FLOW switch is OFF?
Automatically controlled.
What does it mean when the PACK RST SYS FAULT light illuminates?
a PTC fault or a pack overheat is detected, and the respective pack valve will close with the result of a pack shutdown
What happens if PTC A and B fail?
The packs will operate in a backup mode
If PTC A is selected and PTC A fails, does the pack automatically switch to the PTC B?
Yes
T/F: Packs will only operate in HIGH FLOW Mode when the HIGH FLOW Switch is selected ON.
FALSE
Fuel consumption is reduced approximately _______ for each pack in normal flow.
.3%
If all packs are selected OFF, what EICAS Memo Message will display?
Packs OFF
What does the Equipment Cooling System provides cool air to?
Flight Deck Electrical Equipment and for the Electrical and Electronic (E&E) compartments.
What happens to the exhaust air form the E&E compartment on the ground with the engines not operating?
May be routed overboard for warm ambient temperatures or routed to the forward cargo compartment for cold ambient temperatures. The determination of the routing of the air is based upon the ambient temperature, the position of the Lower Lobe Cargo Conditioned Air Flow Rate selector, and the temperature that is selected by the Forward Lower Lobe Cargo Temperature Selector.
When is flight configuration automatically selected for equipment cooling?
When at least 1 engine on each wing is running.
How can flight configuration be manually selected for equipment cooling?
By selecting STBY
What can a EQUIP COOLING EICAS message indicate?
-Equipment cooling airflow is inadequate
-Overheat or smoke detected
-Equipment cooling selector to OVRD and diff pressure for reverse flow cooling is inadequate
-Ground exhaust valve not in commanded position
What is the EQUIP COOLING selector OVRD for?
Ensures equipment cooling when the internal fans are inoperative via reverse airflow
With the aircraft on the ground, no engines running, and cool ambient temperatures, what mode is the Equipment Cooling System operating in?
Flight Mode
T/F: The EICAS caution message EQUIP COOLING displays only when an overheat or smoke is detected in the Equipment Cooling System.
False
What powers the trim air in the lower lobe cargo?
Supplied directly from the bleed air duct