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Preliminary report into Air India crash released

(www.bbc.co.uk)
299 points cjr | 2 comments | 11 Jul 25 20:23 UTC | HN request time: 0.457s | source
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decimalenough ◴[11 Jul 25 21:24 UTC] No.44536914[source]▶
> The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off.

So the fuel supply was cut off intentionally. The switches in question are also built so they cannot be triggered accidentally, they need to be unlocked first by pulling them out.

> In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so.

And both pilots deny doing it.

It's difficult to conclude anything other than murder-suicide.

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userbinator ◴[12 Jul 25 00:53 UTC] No.44538337[source]▶
and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec

Or more precisely, the signals which come from them were found to behave as such.

Without any audible record of turning the switches off, I wouldn't blame the pilots without first checking the wiring and switches themselves for faults. This reminds me of the glitches caused by tin whiskers.

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Epa095 ◴[12 Jul 25 01:56 UTC] No.44538645[source]▶
But from the audio recording it seems like one pilot is noticing them bering in the CUTOFF position, and asking why (and moving it back). If the switch was actually in RUN, but some other issue caused the signal to be sendt, the pilot would see it beeing in the RUN position, not CUTTOF.
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1. michaelmrose ◴[12 Jul 25 05:33 UTC] No.44539581[source]▶
Are they looking at the physical switch or data about the state of the engine displayed in some other fashion?
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2. mrlongroots ◴[12 Jul 25 06:10 UTC] No.44539744[source]▶
This is very clearly EAFR data, so the logical/electrical switch state. Nothing about the mechanical state of the switches has been mentioned, except a picture that shows their final state to be in the RUN position (which makes sense given the relight procedure was ongoing).

From what I understand, the relight procedure involves cycling these back to CUTOFF and then to RUN anyway. So it is not clear if they were mechanically moved from RUN to CUTOFF preceding the loss of thrust, or cycled during relight.