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Preliminary report into Air India crash released

(www.bbc.co.uk)
294 points cjr | 21 comments | 11 Jul 25 20:23 UTC | HN request time: 0.001s | 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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alephnerd ◴[11 Jul 25 21:30 UTC] No.44536951[source]▶
> It's difficult to conclude anything other than murder-suicide.

Is it possible it could have been an accident or a mistake by one of the pilots? How intention-proofed are engine cutoffs?

replies(2): >>44537006 #>>44537365 #
ummonk ◴[11 Jul 25 21:38 UTC] No.44537006[source]▶
You have to pull the switches out (against a spring) to be able to move them over a notch and flip them. Not really something you can just mistake for another switch or bump into by accident.

I'd liken it to turning off the ignition by turning the key while driving your car. Possibly something that could happen if you're really fatigued, but requires quite a mental lapse.

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joezydeco ◴[11 Jul 25 21:51 UTC] No.44537116[source]▶
Report says the switches went to cutoff one second apart from each other. Can a human do the physical operation on two switches that quickly?
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1. snypher ◴[11 Jul 25 21:57 UTC] No.44537174[source]▶
There's a good photo of them here; https://theaircurrent.com/aviation-safety/ai171-investigatio...

You can do them both with one hand.

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2. zihotki ◴[11 Jul 25 22:45 UTC] No.44537551[source]▶
Are you completely sure you can considering that they are spring loaded and they are like 7-10cm apart judging by the size of other controls?
replies(1): >>44537692 #
3. snypher ◴[11 Jul 25 23:04 UTC] No.44537692[source]▶
I don't understand your question. I have done this myself, am I completely sure?
replies(1): >>44537990 #
4. ajb ◴[11 Jul 25 23:15 UTC] No.44537762[source]▶
If you do them both with one hand, would they not be moved at the same instant rather than 1 second apart?
replies(1): >>44537877 #
5. lazide ◴[11 Jul 25 23:31 UTC] No.44537877[source]▶
They require a per-switch motion, so unlikely.
6. cosmicgadget ◴[11 Jul 25 23:50 UTC] No.44537990{3}[source]▶
Did you mean to say you can activate the switches with one hand simultaneously? That is probably what the above commenter assumed you meant. Since lifting and twisting two switches simultaneously with one hand seems challenging.
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7. mvdtnz ◴[12 Jul 25 00:21 UTC] No.44538143{4}[source]▶
It didn't happen simultaneously so this is irrelevant.
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8. cosmicgadget ◴[12 Jul 25 00:40 UTC] No.44538268{5}[source]▶
It is relevant to the interaction I replied to.
replies(2): >>44538646 #>>44539131 #
9. lanna ◴[12 Jul 25 01:15 UTC] No.44538454{4}[source]▶
Above commenter said _quickly_, not simultaneously
replies(1): >>44539161 #
10. arp242 ◴[12 Jul 25 01:42 UTC] No.44538586[source]▶
Is there just one set of switches? Or do both pilots have their own set?
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11. ◴[12 Jul 25 01:56 UTC] No.44538646{6}[source]▶
12. ryandrake ◴[12 Jul 25 03:49 UTC] No.44539131{6}[source]▶
You’re the only one who said “simultaneously.”
replies(1): >>44539209 #
13. cosmicgadget ◴[12 Jul 25 03:56 UTC] No.44539161{5}[source]▶
Jesus...

joey: Can you switch them quickly?

snypher: You can do them with one hand. [Ed. This is ambiguous and could be read as "one hand, simultaneously". In fact, doing it with one hand non-simultaneously would be a weird claim to make of a simple knob. See also ajb's comment below.]

zihotki: Really? They are not close together and have a spring mechanism. [Ed. Seems to believe snypher is claiming simultaneous operation.]

snypher: I am confused by the response.

Me: [Tries to facilitate clarification]

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14. cosmicgadget ◴[12 Jul 25 04:05 UTC] No.44539209{7}[source]▶
See above.
15. JumpCrisscross ◴[12 Jul 25 04:18 UTC] No.44539261{6}[source]▶
> This is ambiguous and could be read as "one hand, simultaneously"

Not within the context of the thread.

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16. ra7 ◴[12 Jul 25 04:29 UTC] No.44539315{7}[source]▶
Context is both these switches being turned off with a 1 second gap. Doing it with one hand simultaneously would possibly explain it, otherwise it doesn’t seem relevant.
17. ExoticPearTree ◴[12 Jul 25 05:33 UTC] No.44539582[source]▶
Only one set.
18. KaiMagnus ◴[12 Jul 25 06:17 UTC] No.44539777[source]▶
I wonder if they could theoretically rest on top of the notch, not fully locked into either position and flip accidentally. No idea how the switches behave when not all the way up or down, but the notch looks pretty long and flat so it could be possible.
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19. sugarpimpdorsey ◴[12 Jul 25 06:28 UTC] No.44539820[source]▶
Those switches are the size of a thumb. No one is moving those - separately, mind you - and not realize what is going on.
20. creato ◴[12 Jul 25 07:31 UTC] No.44540070[source]▶
Something like this could maybe happen to one switch, it's unlikely but possible. But two independent switches at the same time?
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21. KaiMagnus ◴[12 Jul 25 10:06 UTC] No.44540821{3}[source]▶
Good point, that is very unlikely. I was just wondering if it's possible at all.