Fuel System Flashcards
What is the maximum fuel capacity per tank?
- Left wing tank = 7,492 lbs (pressure refueling)
- Left wing tank = 7,290 lbs (gravity refueling)
- Right wing tank = 7,492 lbs (pressure refueling)
- Right wing tank = 7,290 lbs (gravity refueling)
- Center tank = 4,610 lbs (cannot be gravity refueled)
What is the maximum fuel capacity during pressure refueling?
19,594 lbs
What is the maximum fuel capacity during gravity refueling?
14,580 lbs
What is the maximum allowable takeoff fuel in the center tank if each wing tank has less than 4,400 lbs?
500 lbs
What is the minimum fuel quantity in each wing for go-around?
600 lbs and a maximum climb attitude of 10 nose up.
What is the maximum fuel imbalance for the CRJ-700?
- During takeoff = 300 lbs
- During all other phases of flight = 800 lbs
How is the bulk fuel temperature in the wing tanks monitored?
A single temperature probe monitors the temperature of the stored fuel in the right wing tank and displays it on the fuel synoptic page.
What is the source of motive flow for the Transfer Ejectors?
The high pressure output of the Main Ejectors
What is the source of motive flow for the Main and Scavenge Ejectors?
The high pressure engine driven fuel pump
What will supply fuel pressure to the engines if the main ejector pressure is low?
The DC electric boost pumps.
What is the function of the scavenge ejectors?
The scavenge ejectors operate by motive flow and transfer fuel from the wing tanks to the collector tanks.
What is the function of the collector tanks?
The collector tanks keep a full supply of fuel available to the engines at all aircraft attitudes.
What is the location of the collector tanks?
The collector tanks are located in the forward section of the center tank. There is no migration of fuel from the center tank into the collector tanks.
What is the function of the fuel transfer system?
The transfer system moves fuel from the center tank to both wing tanks. This is performed by transfer ejectors and transfer valves located in the center tank. Fuel is then moved from the wing tanks to the collector tanks via the use of scavenge ejectors. The main ejectors receive fuel from their respective collector tank and supply fuel to their engine.
What is the function of the transfer ejectors?
The transfer ejectors transfer fuel from the center tank to the wing tanks.
What controls the fuel transfer from the center to the wing tanks?
The fuel system computer initiates transfer by opening the appropriate fuel transfer valve when the wing tank capacity drops to 94% (7046 lbs). Motive flow from the engine feed manifold passes through the open valve and activates the transfer ejector that move fuel from the center tank to the appropriate wing tank.
When is the fuel transfer terminated after activation?
When the respective wing tank is full, the fuel system computer commands the transfer valve closed. The fuel system computer will cycle the transfer system on and off until the center tank is empty.
What is the function of the main ejectors?
The main ejector takes fuel from its associated collector tank and delivers the fuel to the engine.
What is the definition of fuel crossflow?
Crossflow is the process of moving fuel between wing tanks to balance the wing tank quantities.
What is the function of the fuel crossflow pump?
The crossflow pump is a bi-directional pump that is used to transfer fuel between the wing tanks. When crossflow is required, fuel is taken from the high wing tank by the crossflow pump and then sent to the low wing tank.
What is the function of the automatic power crossflow system?
The power crossflow system provides automatic transfer (crossflow) of fuel from wing to wing to compensate for an imbalance of fuel in the wing tanks. The crossflow is controlled in the automatic mode by the fuel quantity gauging computer whose drivers control a bi-directional crossflow pump in the required direction.
When does the automatic power crossflow activate?
When a fuel imbalance of more than 200 pounds exists between the wing tanks, the computer starts the crossflow pump. Fuel is taken from the high wing tank and pumped to the low wing tank.
When does the automatic power crossflow stop after automatic activation?
The crossflow is stopped when the fuel quanity of the previously low tank exceeds the other by 50 pounds.
What is the function of the XFLOW AUTO OVERRIDE switchlight?
Selecting the XFLOW AUTO OVERRIDE switchlight to MAN on the fuel control panel provides a signal to the fuel computer which inhibits the automatic feature of the power crossflow system.
