"The engines may have spooled down low enough to cause the generators to trip off line...."
Already mentioned elsewhere... A dual gen failure would have deployed the RAT. There is a picture of the aircraft close to where it crossed the airport fence... without the RAT deployed.
"ps Does anyone know whether they tried EEC ALTN or even would it have made any difference IF it had been a FADEC fault? I know that on each start attempt the EEC's (on a 737) use the other channel. Or which thread and page this was discussed?"
Can't recall the thread, but there was a mention of the EPR displays being blanked. This happens if the EEC's
automatically switch to ALTN mode.
Few would therefore dispute that it (the FADEC) determines HP fuel input to the engine. But how would it do that (i.e. schedule the fuel supply rate to the engine) - if it has no access to LP fuel-flow data? Therefore it has "reference ports". But how does the FADEC access these?
As far as I can see, along with all the other engine sensors, the Trent EEC assesses fuel flow simply by monitoring the position of the EEC-controlled fuel metering valve in the FMU. There is also a Pressure Drop and Spill Valve to keep a constant differential pressure across the fuel metering valve. This is similar to the regulation on the RB211.