Fuel System Flashcards
What is the tank capacity of the CRJ550?
Pressure fuelled - 19594 lb total.
7492 lb left and right.
4610 ll centre.
Gravity fuelled - 14580 lb total.
7290 left and right.
How is fuel prevented from flowing outwards from tne wing route?
One way flow valves.
Where are the collector tanks located?
In the centre tank lower than both wing tanks.
How is fuel sent to the collector tanks?
Gravity and scavenge pumps from the onside wing tanks.
How is fuel quantity determined?
By a DC capacitance type system. Various probes in each tanks and a compensator unit determines fuel density.
Where is the bulk fuel temperature probe?
In the right tank.
How is motive flow generated?
By action of the engine driven fuel pumps and venturi ejector pumps.
How is fuel transferred from the centre tank to the wing tanks?
Automatically whenever there is motive flow and the transfer shutoff valves are open. The shutoff valves open when the wing tanks are less than 94% full and close when the main tanks reach 97%.
What is the purpose of the check valves?
To prevent fuel from flowing backwards through the system.
To allow either fuel pump fuel to both engines, but prohibit the main ejectors feeding the opposite side engine.
What is the purpose of the fuel pumps?
Provide fuel pressure for engine start and backup pressure if the motive flow system fails.
What happens when the fuel boost pump switchlights are depressed?
When both switches are out, both pumps are off.
When one switch is depressed, pressure switches determine if the pumps should operate or not.
How is lateral fuel balance managed?
Powered cross flow and gravity cross flow.
Where is the single point pressure refuelling adapter?
At the right wing root.
When will automatic fuel crossflow begin/stop?
It initiates when the difference in the tanks is 200 lb. Fuel is transferred to the lower tank until it exceeds the fuller tank by 50 lb.
