Fuel System Flashcards
Describe the fuel system
Two separate, but identical fuel systems connected by a valve controlled cross feed line. The MC-12 is capable of carrying 775 gallons of JP8 in three different sets fuel tanks
The fuel system consists of the following subsystems:
Storage Systems (Tanks, Vents, Drains & Indicators) Distribution Systems (Fuel Pumps, Valves, & Fuel Control)
What are the fuel capacities for each of the separate fuel tanks.
Wing Tank = 190 Usable Gallons 136 Wing & 54 Nacelle Auxiliary Tank = 79.5 Usable Gallons ER Tank = 118 Usable Gallons
Do not put any fuel into the _____ tanks unless the ______ tanks are full.
Do not put any fuel into the auxiliary tanks unless the main tanks are full.
How many vents are located on the underside of the wing adjacent to the nacelle?
- Each serves a backup to the other if one becomes blocked.
What is the purpose of the fuel vent system?
Keeps positive pressure in the main tanks to allow gravity feed.
What happens when fuel expands due to heat?
If the main tank is full, and the aux tank if empty, fuel vents into the aux.
If both tanks are full, the fuel vents down the leading edge and through the heated fuel vent.
What is the fuel capacity of the Nacelle Tank?
54 gallons
What can happen if the fuel vents become clogged?
Fuel can become trapped in the system causing an early flame-out.
If fuel remains in the auxiliary tank and the NO FUEL XFR annunciator stays illuminated, What is happening and what are your actions?
This indicates that the motive flow valve is still closed. Place the XFR OVERRIDE switch to AUX.
L/R FUEL QTY illuminates indicating what?
Approx 30 minutes (45 gallons) of fuel remaining per engine at maximum continuous power.
The Jet Pump in the ER and Aux Tanks are:
a. Mechanical
b. Electric
c. Bleed air driven
d. Operating when fuel flows through it.
d. Operating when fuel flows through them.
The Auxiliary fuel transfer system is fully ________ and is only __________ by the pilot.
The Auxiliary fuel transfer system is fully automatic and is only monitored by the pilot.
What is the consideration concerning Manual Transfer Override with the ER system?
The pilot must place the switch back into AUTO or AUX when the ER Tank is empty.
Engine Driven Boost Pump is how many psi?
What does it share with the oil pump?
30 psi
Shares the same drive shaft as the oil pumps
What is this?
Engine Driven Boost Pump
(Low Pressure 25-30psi)
What is this?
Engine Driven Fuel Pump
900-1100 (High Pressure)
Failure of the high Pressure Pump results in engine flameout
What is the purpose of the Oil-to-Fuel Heat Exchanger?
Used to heat fuel and vaporize water crystals to prevent fuel filter blockage inside the fuel control.
I am a drop of fuel. What is my path from the tanks to the engine?
How many fuel pumps are there on each side of the aircraft?
5
Engine Driven Boost Pump
Standby Boost Pump
High Pressure Pump
Jet Transfer Pump (ER)
Jet Transfer Pump (AUX)
Which sequence of components correctly defines the flow of the fuel from the Firewall Shutoff Valve to the Fuel Manifold?
Engine Driven Boost Pump, Fuel Filter, Oil-to-Fuel Heat Exchanger - High Pressure Pump - Fuel Control Unit - Fuel Flow Transmitter
How many fuel nozzles are there on the engine?
Are they simplex or dualplex?
14 simplex
Which component in the fuel system shares the same drive shaft as the oil scavenge pumps?
Engine Driven Boost Pump
- If the Engine Boost Pump fails, the oil scavenge pump may also be affected.
What happens during crossfeed operations?
- CROSSFEED light illuminates.
- Crossfeed Valve opens
- STBY Pump on supply side energizes.
- Motive flow valve on receiving side closes
The Left or Right FUEL PRESS warning light is designed to tell you when:
The Engine Driven Fuel Boost Pump has failed.
What does the fuel ER/AUX XFR override switch do?
Provides electrical power directly to the respective motive flow valve.
How long can you operate with the red FUEL PRESS warning light illuminated?
10 hours
If the High Pressure Pump fails, what will happen?
The engine will fail.
What is the maximum fuel imbalance?
300 lbs.
The minimum fuel required for takeoff is how many pounds?
265 lbs in the main tanks.
How many Standby Pumps are required for takeoff?
One STANDBY PUMP can be inoperative for takeoff.
What limitations are placed on operations with AVGAS?
Limited to 150 hours.
Requires standby boost pumps to be used above 15,000 feet.
