ATA 73 - Fuel System Flashcards
When will the fuel filter caption (amber light) indcate on the fuel panel?
When the differential pressure reach 9 psid (the indication will disappear at 5 psid)
When will actual bypass valve open? (fuel filter)
At 20 psid
What is powering the fuel flow transmitter?
No electrical power is needed. The unit is driven from the fluids flowing through it.
Which are the Fuel Control Modes?
- Normal power mode (constant speeding above flight idle determined by the power lever)
- Bottoming governor mode (1040/1200 rpm hold)
- Bottoming governor mode (CTOT & APR hold)
- Bottoming Governor Disabled Mode (Normal power mode controlled by the condition lever)
When will the bottoming governor be enabled?
When the condition lever passes 39° (it is active with the condition lever at MIN position 42° CLA or above)
Which Np is held by the Bottoming Governor?
1040 rmp (or 1200 rpm at maximum reverse thrust)
How is the CTOT & APR hold enabled?
Manually selected by the crew and the power lever selected to a position above take-off position (64° PLA switch)
When is normal power mode (constant speed) held by the propeller pitch control unit?
Between 1180 (MIN) and 1384 (MAX) propeller rpm
Which are the 3 main functions of the ODV (Overspeed & Drain Valve)
- Provide main fuel to the 12 injectors
- Divert fuel flow from being delivered to the
engine when the DECU actuates the overspeed solenoid - Purge main fuel manifold when engine is stop cocked
When will the ODV shut off the fuel supply?
When it gets a shut-off signal from the DECU (if both channels detect overspeed condition 1570 propeller rpm)
Which are the two main units in the fuel control system?
- Hydromechanical Control Unit (HMU)
- DECU/ECU
Where is the HMU located?
Aft side of the AGB
