Originally published at: Fuel Cutoff Switches Eyed in Air India Dreamliner Crash - AVweb
“Improper, inadvertent, or intentional actions" cannot be ruled out.
Hmm. If you’ve done everything and know you’re going in would you shut off the engines last minute, maybe closing some valves and deactivating fuel pumps?
No. If you were at altitude and an engine shut down you would follow the engine restart procedure in the manual which probably requires closing a fuel valve. When you have landed there is an engine shutdown procedure which involves turning off the fuel switches.
I’m suspecting “suicide by pilot” … one could reach behind the console and turn off the fuel which would cause a dual engine shut down, as this article surmises.
A known fact is that the FSOVs on the engines will close if the electrical system re-boots or has a momentary power-down. On top of that the electrical system will re-boot on its own, if left powered up continuously for a set period of time, whether it is on the ground or in the air.
The deployment of the RAT and the interruption of the U/C retraction, point to an electrical failure, which is unlikely to be due to crew actions.
Not necessarily. A shutdown would cause the RAT to deploy. You can’t say which came first.
Surprised (and I’m not familiar with the 787) that it wouldn’t be configured like the E190. The shutdown switches do nothing unless the power levers are at idle. This is to prevent inadvertent shutdowns
No. That is not a fact at all! Nice try with the google search though. The FSOV on each engine is actually powered by the EEC (FADEC) which is powered by a Permanent Magnetic Alternator (PMA) located on the accessory drive of the engine, completely independent from the rest of electrical system of the aircraft. The Spar valve for each engine is powered by the Main battery on the Hot Battery Bus (and thus always powered) and is commanded by the EEC to open or close. The engine cutoff switches and fire switches are connected directly to the EEC. So a complete AC electrical system failure will NOT cause both engines to shut down. And neither will a DC electrical system failure. Even if the engine is windmilling, the PMA can provide power to the EEC and the main battery will power the spar valve and engine igniters (through the standby inverter) allowing the EEC to attempt to relight the engine.
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Rushing through an emergency could lead you to turn off the wrong cutoff followed by a “whoops” and then cycle the intended engine’ cutoff, without sufficient altitude and airspeed to relight. No saying if anything remotely similar occurred here, but the scenario seems plausible.
Thanks for that. I knew that if I spouted BS I would get pukka gen thrown back at me!