OTTOMH - The "default" without power is for the engine to run. It requires power to the shutoff valve to stop, so if you remove power it reverts to "run" and fuel will flow.
The FADEC doesn't really do much at all during start, if the engine has fuel and ignition and you spin it with the starter it will start. The EEC only has a watchdog on the ITT and may bump the fuel flow back slightly but that is about all until idle is reached.
Pretty easy fix - leave the master on until N1 = 0%? Fairly good practice to avoid after-fires on any turbine and probably says the same in the RFM?
Turning off the master SW too early can also lead to DCU data write corruption as it uses an N1 speed to trigger the write function and of course needs power to do so.
Last edited by RVDT; 25th July 2024 at 03:56.