Air India crash

[Reynard]

Tomorrow is the anniversary, and theoretically a ‘final’ investigation report should be forthcoming.  
 

There is skepticism that the final report will provide anything conclusive, or indeed that a report will be issued at all in the expected timeframe.

[onetrack]

The Indian Air Accident Investigation Bureau is obliged to hand down a report on Friday 12th June. It will not be the final report. It will still only be an interim report. This is because the examinations of the engines and electronic systems of the crashed aircraft are still not complete. It will take much longer for a final report - and perhaps even then, there will still be doubt over the conclusions of the investigation.

 

Essentially, the crash boils down to one of two scenarios. One, the Capt threw the fuel cutoff switches to off and then returned them to on, too late to recover. Tim Atkinson, a former British air crash investigator is convinced there is no other cause, but that the Capt threw the engine fuel switches to off - and blames his actions as a homicide-suicide. 

Another Indian investigative journalist is pursuing a line that the switches in the cockpit were never moved, and the engine shutdown was a result of some kind of short circuit in the electronics that shut the fuel off, without the switches in the cockpit being activated. Aircraft manufacturers and designers state the 787 design, absolutely precludes any such possibility.

 

My take is that because around 90% of aircraft accidents are caused by errors on the part of the crew, the law of averages would support the cause of the crash being physical action on the part of the Captain, in throwing the fuel switches to off. To say he did that, in a suicidal moment, is taking things too far, IMO.

I would suggest he threw the fuel switches to off, in a moment of mental confusion/stress/work overload/absentmindedness, without even being aware of doing so, for several seconds. Then when he realised what he'd done, he threw the switches back to on, in a desperate attempt to recover adequate flight speed.

The very best of highly trained people have "Oh, sh**!!" moments, when they make a serious error in equipment operation, especially at critical times. In this case, I believe it was a mental distraction error at the worst possible time, and it was one that was unrecoverable from, due to engine response lag. I believe it's unlikely we'll see a final report, for possibly at least another 12 months.

[pmccarthy]

Apparently the RAT deployed while it was still on the ground, before the switches turned off.

[onetrack]

If that can be proven, then the possibility of the fuel cutoffs being activated without physical movement of the switches in the cockpit increases.

 

But there's two engines, two separate fuel systems, two fuel cutoff switches, and the electrics and hydraulics on each side operate largely independently. It doesn't seem possible that any electrical fault in the aircraft would actuate both fuel cutoff switches. Unless it was a short-circuit that closed both cutoff switch circuits at once.

 

Something crushing the cutoff switch wiring to both switches, so bare wires were shorted, seems the only likely scenario. But that would have to be an intermittent crush, for the cutoff switches to be able to be switched back on again, as the initial report says they were.