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Preliminary report into Air India crash released

bbc.co.uk

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Re: Preliminary report into Air India crash released

#511

Post by briandear »

sillysaurusx wrote: post #50
lazystar wrote: post #17

Earlier quoted context omitted.

https://ad.easa.europa.eu/ad/NM-18-33 well hold your horses there... from the FAA in their 2019 report linked above: > The Boeing Company (Boeing) received reports from operators of Model 737 airplanes that the fuel control switches were installed with the locking feature disengaged. The fuel control switches (or engine start switches) are installed on the control stand in the flight deck and used by the pilot to sup…

https://www.youtube.com/live/SE0BetkXsLg?si=LPss_su3PVTAqGCO Both of these extremely-experienced pilots say that there was near zero chance that the fuel switches were unintentionally moved. They were switched off within one second of each other, which rules out most failure scenarios. If it was an issue with the switches, we also would have seen an air worthiness directive being issued. But they didn’t, because this…

My buddy says the same, he’s a 787 captain for United. Essentially impossible to accidentally turn off those switches. My buddy isn’t “evidence” of course, but actual airline captains are all saying similar things.

Re: Preliminary report into Air India crash released

#512

Post by shash »

apical_dendrite wrote: post #234
userbinator wrote: post #193

Earlier quoted context omitted.

A rodent chewing on wires. Vibration-induced chafing. Tin whiskers causing an intermittent short. There are many possibilities, those came to mind first.

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.

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.

Re: Preliminary report into Air India crash released

#513

Post by [deleted] »

userbinator wrote: post #442
Epa095 wrote: post #211

Earlier quoted context omitted.

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.

Where can I listen to this recording?

[deleted]

Re: Preliminary report into Air India crash released

#514

Post by shash »

fyrn_ wrote: post #428
apical_dendrite wrote: post #234

Earlier quoted context omitted.

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.

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

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.

Re: Preliminary report into Air India crash released

#515

Post by yread »

epolanski wrote: post #289
burnt-resistor wrote: post #275

Earlier quoted context omitted.

> It's difficult to conclude anything other than murder-suicide. You're leaping into the minds of others and drawing conclusions of their intent. One of them moved the levers. It could've been an unplanned reaction, a terrible mistake, or it could've been intentional. We may never know the intention even with a comprehensive and complete investigation. To claim otherwise is arrogance.

The car equivalent is being on a highway and "mistakenly" pulling the hand brakes, except that there are 2 hand brakes and you need to first unlock both of them. That's very hard to do by panic and mistake, if not impossible by design.

On pprune there is a professional pilot that says they had multiple instances of inadverent switching off fuel switches. They do it every startup, shutdown and training captains (the captain on this flight was pilot not flying, he had >10k hours) do it all the time in the sim to trigger engine out scenario during training

Re: Preliminary report into Air India crash released

#516

Post by shash »

Spooky23 wrote: post #299
chupchap wrote: post #12

Earlier quoted context omitted.

Or a mechanical failure

Serious question: why is it so difficult to fathom that a deranged pilot could decide to commit suicide by plane?

Not difficult, but can you close an investigation on that note without going over other possibilities?

What if there's another safety lesson to be learnt here?

Re: Preliminary report into Air India crash released

#517

Post by VBprogrammer »

mdavid626 wrote: post #45
lazystar wrote: post #17

Earlier quoted context omitted.

https://ad.easa.europa.eu/ad/NM-18-33 well hold your horses there... from the FAA in their 2019 report linked above: > The Boeing Company (Boeing) received reports from operators of Model 737 airplanes that the fuel control switches were installed with the locking feature disengaged. The fuel control switches (or engine start switches) are installed on the control stand in the flight deck and used by the pilot to sup…

Well, can you move it back, when accidentally activated?

In older turbine aircraft this would cause a hot start or worse. It would be interesting to know what the FADEC systems do in this case.

Re: Preliminary report into Air India crash released

#518

Post by bravesoul2 »

macintux wrote: post #245
747fulloftapes wrote: post #139

Earlier quoted context omitted.

The landing gear lever is rather prominently featured in the 787 in a panel central to the cockpit layout so that either pilot can easily reach it. For decades and across many manufacturers, the landing gear lever has traditionally featured a knob that deliberately resembles an airplane wheel. It's very hard to mistake it for anything else. It's actuated by simply moving it up or down. The fuel control switches are b…

> This idea strikes me as even more unlikely than someone shifting their moving vehicle into reverse while intending to activate the window wipers. I suspect you've never driven an older vehicle with the shifter on the steering column.

But if he did, would have done hours of retraining in a simulator?

Re: Preliminary report into Air India crash released

#519

Post by bravesoul2 »

Mawr wrote: post #448
cjbprime wrote: post #156

Earlier quoted context omitted.

> There is no possible way to confuse these two actions. This is obviously an overstatement. Any two regularly performed actions can be confused. Sometimes (when tired or distracted) I've walked into my bathroom intending to shave, but mistakenly brushed my teeth and left. My toothbrush and razor are not similar in function or placement.

That's just your brain associating the bathroom with the act of brushing your teeth, and therefore doing it automatically upon the trigger of entering the bathroom. It bears no resemblance to the accidental activation of a completely different button. The other poster's correction: "it’s like brushing your teeth with razor" is apt. Touching the fuel cutoff switches is not part of any procedure remotely relevant to th…

I agree. Has anyone here unplugged their mouse instead of pressing caps lock by mistake?

Re: Preliminary report into Air India crash released

#520

Post by shash »

bgwalter wrote: post #75
cosmicgadget wrote: post #54

Earlier quoted context omitted.

Murder-suicide has happened on a few occasions. How many times has your malfunction occurred on an aircraft fuel system?

Not precisely the electrical malfunction, but dual engine shutdown has occurred, fortunately after landing: https://www.aerosociety.com/news/ana-787-engine-shutdown/

Different engine (those are Trents and this was a GEnx), but yeah, that _did_ happen.
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