ORIGINAL: FalconWings
I think the shutoff valve should absolutely be just before the turbine "inlet", downstream of the solenoid and pump. Thats why it is a shutoff valve.
Let me explain myself.....say if you have a very long fuel line after the pump and the engine catches fire. If the shutoff valve is upstream of the pump, you can still have a lot of fuel trapped inside the fuel line that could still make it to the engine, therefore feeding the flame. If the shutoff valve is closer to the engine, any trapped fuel in the engine feed line would be blocked from entering the turbine.
David
With due respect, the length of the fuel lines does not matter if the line is shut off, to prove it fill a tube with water, block one end then try and suck the water out the other end, unless the tube collapses you will not get anything out of the tube.
My thinking is as long as the ECU is still OK shut off the Tx this should put you into fail safe and shut off the turbine, if safe shut off your manual valve, then douse the flames.
Mike