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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

#481

Post by Simon_O_Rourke »

decimalenough wrote: post #11

> 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 swi…

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

The balance of probability might tend to support that hypothesis. However I'm wondering if it was just something involuntary. My ex for instance who learned to drive on a stick shift would randomly stall the engine after a few weeks driving an automatic.

Re: Preliminary report into Air India crash released

#482

Post by ionwake »

Aurornis wrote: post #345
prepend wrote: post #228

Earlier quoted context omitted.

I once worked with a software engineer who would do things and then bald face lie about it. This reminds me of that person. Me: “The build is breaking right after you checked in. Why did you do that?” Him:”I did not do so.” Me: “The commit shows it as you. And when I rolled back everything builds.” Him:”It must have been someone else.” That person was really annoying.

I’ve worked with some chronic liars. They would deny reality no matter how much evidence you had. The weirdest thing was how often it worked for them. In each case their lying eventually caught up with them, but in some cases they’d get away with lying for years. It’s amazing how often someone would have clear evidence against what they were saying, but the people in positions of authority just wanted to de-escalate…

i worked in many companies but I always remember one , where during a public chat in the middle of an open office the programmer next to me (who was always conniving but I just ignored it ), said incorrectly something akin to " yes I know all about that source control its... based on locking " , the whole point was that although locking technically occurs, the SC would allow different coders to work on it at the same time. The non technical manager said correctly, "no the whole point is that the codebase isnt locked", to which the programmer replied " yeah thats what I mean".

In that moment I realised he was just bare faced lying right infront of everyone, about a technical subject, only HE should be the expert in, and to this day I am perplexed why his contract kept being renewed.

Eventually I was let go ( he possibly suggested I be let go ) for an incident that was unrelated to me.

This is all fine, but i learnt 5 years on he was still being paid a top 1% salary at the same company.

I promise the point isnt that I am jealous, its that this guy, who was a sub par coder and liar, somehow managed to keep his job whilst everyone else lost theirs and earnt untold amount in England ( where salaries are always low).

My goodness - I just remembered he was found by police driving a vehicle seemingly under the influence on a motorway, work found out after the police called them, and somehow he turned up the next day at work , lied about it, and STILL kept his job.

I am only mentioning this guy , because he was NOT a nepotist hire, he was just some guy who would lie and somehow people were ok with it. I still think of him often and wish I could have learnt more from his abilities just out of interest.

Re: Preliminary report into Air India crash released

#483

Post by bestouff »

melenaboija wrote: post #353

I'm completely ignorant about this matter, but why is it even possible to cut off fuel while taking off? Shouldn't there be a control that completely disables this? Is there actually a situation where cutting off both engines could be necessary and wouldn't lead to a catastrophe?

Airbus liners don't allow cutting fuel with trust lever on.

Re: Preliminary report into Air India crash released

#484

Post by jon_smark »

sgt101 wrote: post #462
decimalenough wrote: post #370

Earlier quoted context omitted.

The issue with the 737 MAX became evident within months of the plane's launch. By contrast, the Dreamliner has accumulated over a decade of flying history across over 1000 aircraft with precisely zero fatal accidents.

Absence of evidence isn't evidence of absence. The fact that the pilots denied that they had shut the switch (one asking the other why they had done so and the other denying it), and that they restarted the engines should be taken into account. Ok, murder suicide is definitely on the table but I would want to see some other reasons for believing that this is so.

Sorry to nitpick, but for a good Bayesian, absence if evidence is evidence of absence. If you want the aphorism to be technically correct, you should say "absence of proof is not proof of absence".

A note on the terminology: "evidence" is a piece of data that suggests a conclusion, while not being conclusive by itself. Whereas "proof" is a piece of data that is conclusive by itself.

Re: Preliminary report into Air India crash released

#485

Post by bestouff »

chii wrote: post #436
m101 wrote: post #387

What makes me more inclined to suicide is that this might have been the perfect time to do this so that even a small interruption in fuel would be catastrophic.

If this is the case, you have to then think about why this pilot would want suicide but also murder all aboard the plane. It's a bit irrational if they wanted to just suicide - you can easily just cut your own throat, hang yourself, or jump off a tall building.

There are already 5 other cases of pilot suicide with a full plane.

Re: Preliminary report into Air India crash released

#486

Post by [deleted] »

Velorivox wrote: post #350
decimalenough wrote: post #11

> 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 swi…

This is highly reminiscent to me of this case. [0] The co-pilot accidentally hit the wrong switch and then quietly corrected his mistake later, without resetting the previous switch (which led to feathering). [0] https://en.wikipedia.org/wiki/Yeti_Airlines_Flight_691

[deleted]

Re: Preliminary report into Air India crash released

#487

Post by fakedang »

abracadaniel wrote: post #312
mcpeepants wrote: post #252

Earlier quoted context omitted.

Is actuating the fuel cutoff switches something that is done routinely in these aircraft, to the extent it could reasonably become muscle memory? ETA: downthread it is mentioned that these switches are used on the ground to cut the engines

Seems akin to something like a parking brake. Something you only use at a stop, or rarely during an emergency.

They're pilots, they do hundreds of stops each year. In case of domestic pilots, even thousands. And with years of experience, switching off fuel control switches is basically muscle memory at this time now.

Re: Preliminary report into Air India crash released

#488

Post by fakedang »

callmeal wrote: post #443
sugarpimpdorsey wrote: post #348

Excellent analysis here, those switches are stout, no one is moving them by accident: https://www.youtube.com/watch?v=wA_UZeHZwSw

Except when they are not: From the avherald link: >Service Bulletins by Boeing issued in year 2018 recommending to upgrade the fuel switches to locked versions to prevent inadvertent flip of the switches, as well as the FAA/GE issued Service Bulletin FAA-2021-0273-0013 Attachment 2 relating to loss of control issue (also see above) were NOT implemented by Air India.

Because that maintenance check is an optional one as stipulated by Boeing. I don't think most users of the 787 themselves carry out the check, so singling out Air India for this alone is just bad faith

Re: Preliminary report into Air India crash released

#489

Post by gosub100 »

ummonk wrote: post #19
decimalenough wrote: post #11

> 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 swi…

Yeah and the other pilot flipped the switches back on and one of the engines started spooling up but it was too late. Murder-suicide looks like the likely conclusion, given that flipping the cutoff switches requires a very deliberate action. That said, it's not entirely impossible that due to stress or fatigue the pilot had some kind of mental lapse and post-flight muscle memory (of shutting off the engines) kicked i…

> Murder-suicide looks like the likely conclusion

But why cutoff the fuel instead of flying into terrain? It's such a passive action

Re: Preliminary report into Air India crash released

#490

Post by padjo »

throwawayben wrote: post #469
padjo wrote: post #380

Earlier quoted context omitted.

It’s nowhere near an obvious conclusion. A failure with the locking mechanism or muscle memory confusion are just as likely, and probably other theories I’m not thinking of. More investigation is clearly needed, which is why this is called a preliminary report.

Dual failure of the locking mechanism is extremely unlikely. These are not switches that are regularly used so a muscle memory issue also seems very unlikely (but is still the most likely non-suicide scenario)

If the switches have an unknown design flaw then it’s unknown how likely it is they’d both fail simultaneously

My understanding is these switches are used routinely during the shutdown procedure or did I get that wrong?

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