Fuel System Flashcards
Total: Amount of usable fuel in the 2 main tanks, and 2 auxiliary’s.
386 gallons and 158.
Do the main and auxiliary share the same filler?
No, they are separate
Explain the normal fuel routing from the main tank:
In the following order: Main tank > Nacelle tank > Fuel strainer > Firewall shutoff valve > Engine driven boost pump (low pressure) > firewall fuel filter > Fuel pressure switch > Fuel flow transmitter > Fuel heater > Engine Fuel Pump (high pressure) > FCU. A standby fuel boost pump is installed with its own strainer.
Explain the auxiliary fuel routing and how it operates.
In the following order. Auxiliary tank > Fuel strainer > Jet pump > Nacelle tank > fuel strainer > firewall shut-off valve > boost pump (low pressure) > firewall shutoff filter > Motive Flow Valve > Jet fuel pump (and the process repeats).
The auxiliary fuel pump use a motive fuel system: From the nacelle tank after passing the boost pump and firewall shutoff strainer, a fuel line is routed to the aux tank. when fuel passes through the jet pump it pulls fuel from the aux tank, feeding it to the nacelle tank, using the venturi principle.
Is the auxiliary fuel supply automatic or pilot activated?
Automatic. It utilizes motive fuel from the low pressure boost pump to ‘suck’ fuel from the auxiliary tank.
During engine start the automatic fuel transfer system (auxiliary fuel transfer) have a delay. How long is this delay and why does it exist?
30 - 60 seconds. I delay exist to provide maximum fuel pressure for the engine during start. After the delay the “NO TRANSFER” on the fuel panel will extinguish.
If there is malfunction with the Automatic Aux Transfer system, how can the motive fuel valve be manually opened?
The motive flow valve may be manually energized to the open position by placing the AUXILIARY TRANSFER switch, normally in the AUTO position, to the OVERRIDE posi- tion. This procedure will bypass the automatic feature in the auxiliary transfer system and send DC power directly to the mo- tive flow valve.
Where can the firewall fuel shutoff valve switches be found? And it what state must the battery master switch be for them to function?
Below the fuel control panel.
The firewall shutoff valves are connected to the hot battery bus. They can be operated with or without the batt switch in the on position.
How is fuel heated in the fuel heater?
Using warm oil from the engine and heated via a heat exchanger
When is crossfeed permitted?
Only emergencies such as single engine operations
What type is the fuel gauging system? And the maximum error?
Capacitance type system. Maximum of 3%
Number of fuel drains and location?
6 per side: 3 underneath engine cowling, 1 near tip of the wing forward of the aileron, 1 near the leading edge outboard of the engine nacelle, and 1 center of the wing close to the fuselage.
Under which amount of fuel per quantity gage (main or aux) is take-off not allowed?
265 pounds (yellow arc)
