Air India B787 crash Ahmedabad

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Earlier aircraft had contact sensors on these sorts of switches, but technology has come a long way and now they would likely be Reed switches or possibly even Hall effect switches as these can output a digital signal. Given that when these fuel control switches are moved to the run position the FADEC uses this information to commence the ignition/start up sequence of each engine it is quite possible that a Hall effect switch sensor could be what is fitted - or there is no sensor on the actual switches and instead down stream of the switch there is a sensor or takeoff that basically says "I'm getting power now - so therefore the switch has been moved from cutoff to run"

@AviatorInsight - if you happen to be talking to any LAME's who are really clued up on the electricals it would be good to ask them which method is used to detect that the switch has been moved?
I'm not a pilot but trying to make sense of the way the fuel switches work on the 787-8 suggests optic fibres to the EEC + FADEC. There seem to be 2 fuel valves per engine one graduated and the other on/off. I thought I'd read that the graduated one at the v least would respond to a drop in fuel pressure by constricting the flow. In this sense would it be at all possible that something similar happened due to vapour which the computers then responded to by closing both valves until the fuel pressure got restored ? It's not inconceivable the following 10s delay was the time taken to purge vapour from the lines and reestablish or reopen the valves once fuel pressure was restored. I don't think the spring loaded switches in the coughpit would have had to move for any of these changes to have taken place, although the pilot flying would have lost his instrumentation when the RAT deployed as only the left hand arrays remain on
 

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