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Preliminary report into Air India crash released

(www.bbc.co.uk)
294 points cjr | 10 comments | 11 Jul 25 20:23 UTC | HN request time: 1.326s | source | bottom
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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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chupchap ◴[11 Jul 25 21:29 UTC] No.44536947[source]▶
Or a mechanical failure
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ceejayoz ◴[11 Jul 25 21:30 UTC] No.44536955[source]▶
Both switches, at slightly different times? Seems pretty unlikely.
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1. userbinator ◴[12 Jul 25 01:35 UTC] No.44538547[source]▶
A rodent chewing on wires. Vibration-induced chafing. Tin whiskers causing an intermittent short. There are many possibilities, those came to mind first.
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2. Epa095 ◴[12 Jul 25 01:59 UTC] No.44538655[source]▶
But why does the pilot then comment that they are in the CUTTOF position and move it to RUN? A mechanical failure would have to also move the physical switch in the cockpit for the audio recording to make sence.
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3. userbinator ◴[12 Jul 25 02:05 UTC] No.44538690[source]▶
You have the exact CVR audio? The report says "one of the pilots is heard asking the other why did he cutoff" which I interpreted to mean one of them noticed the engines shutting down, and asked the other if he did that.
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4. apical_dendrite ◴[12 Jul 25 02:40 UTC] No.44538849[source]▶
We know that the switches physically moved from the run to the cutoff position because one of the pilots noted that they were in the wrong position. We know that they were moved back to the run position because they found in that position. I don't understand how a short could explain that - it really seems like someone would have had to physically move the switches.
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5. bronson ◴[12 Jul 25 02:57 UTC] No.44538922{3}[source]▶
Then he would have asked the other pilot why the engines are shutting down. It seems a lot more probable that he glanced at the switches before asking such an explicit question.
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6. userbinator ◴[12 Jul 25 04:09 UTC] No.44539227{4}[source]▶
Without listening to the CVR audio and knowing what they actually said, there's no evidence either way, and AFAIK they have not released that.
7. fyrn_ ◴[12 Jul 25 08:25 UTC] No.44540293[source]▶
Do we know that the pilot noticed they were in the wrong physical position, or did some other status indicate the engie fuel had been cut? I would be surprised if there was only one channel for this information
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8. shash ◴[12 Jul 25 12:06 UTC] No.44541490[source]▶
What we have is reported speech: "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."

So we don't know the exact words used. Did he say for example, "Why did you move the switches to cutoff" or did he ask "Why did you cut off the engines"? If there are indeed two shorts (astronomically low as those probabilities are), the other pilot would say "I didn't", look around confused and then (possibly?) flip both of them down and back up? Which could explain the 4s delay in pulling them back up.

Speculation, but since we do not have actual transcripts or recordings, all I'm doing is answering speculation with more speculation.

9. shash ◴[12 Jul 25 12:09 UTC] No.44541508{3}[source]▶
In the last mentour pilot livestream, they showed the simulator and both engines, and there's a little graphic near the cutoffs showing engine state and performance. Also, in _this_ livestream as soon as the report was released, Ben mentions in response to a question that if you cut off the engine, a lot of electrical systems are going to face power cuts, so there will be alarms blaring all over the cockpit. So, yes. There are many channels of information here.
10. mr_toad ◴[12 Jul 25 12:44 UTC] No.44541670[source]▶
It amazes me that some people can ever make it out the door if they spend all their lives contemplating a series of increasingly unlikely possibilities.