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Preliminary report into Air India crash released

bbc.co.uk

491–500 of 924 posts

Re: Preliminary report into Air India crash released

#491

Earlier quoted context omitted.

> One of them moved the levers. It could've been an unplanned reaction, a terrible mistake, or it could've been intentional. Fuel levers are designed to only be moved deliberately; they cannot be mistaken for something else by a professional pilot. It's literally their job to know where these buttons are, what they do, and when to (not) push them. It's not arrogance to assume the most likely conclusion is true, despi…

> cannot be mistaken for something else Assumption. Big ass assumption. Pilot are trained until actions are instinctual and certain memory items are almost unconscious. But pilots are still people and people are fallible and make mistakes, and sometimes act unreasonably. Intent cannot be determined without clear evidence or statements because that's now how thoughts locked away in people's minds work. > It's not arro…

> sometimes act unreasonably. Intent cannot be determined without clear evidence or statements because that's now how thoughts locked away in people's minds work.

By this logic it would be impossible to ever find anyone guilty of murder (or any other nefarious action) with intent unless they explicitly state that it was in fact their intent. Obviously this is not how justice works anywhere, because at some point you have to assume that the overwhelmingly most likely reason for doing an action was the true reason.

If someone pulls out a gun, cock it, aim it at someone and pull the trigger, killing the other person, should we hold off any judgement because they might have done it purely mechanically while in their head thinking about the lasagna they are going to cook tonight and not realizing what they were doing ?

The fuel cut off switches have a unique design, texture and sequence of action that need to be taken to actuate them, they don’t behave like any other switch. Pilot are also absolutely not trained to engage with those particular switches until it’s instinctual.

Re: Preliminary report into Air India crash released

#492

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…

What is "01 second" as quoted above? If it's 1 second, you could possibly conclude that it was intentional. If it's 0.1 second you might think it was an accident and the lock was disengaged.

There is no electronic lock as far as I know, as many people seem to assume. It's a mechanical notch that you have to physically pull the switch past to operate it. The lock failures described in the air worthiness directive was about this mechanical stop or notch not being installed.

Re: Preliminary report into Air India crash released

#493

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.

This is actually very clever and elegant!

Re: Preliminary report into Air India crash released

#494
post #60

Earlier quoted context omitted.

Airlines are decades behind on tech. You can get satellite internet almost anywhere on the planet and GPS can give you ten-foot accurate positioning, but we've still _lost_ planes because we haven't mandated a system that sends the realtime position of the plane over the satellite internet. The days of limited storage are still going strong in the industry.

There are reasons they don’t. This is a deceptively difficult problem Cost is a big one (satellite data is still quite a bit more expensive than you think, especially with many stations) And by stations, I mean aircraft. There are a TON. Current constellations probably wouldn’t even be able to handle half the current aircraft transmitting all at once. Bandwidth, in the physical sense, becomes a limiting factor Covera…

> Cost is a big one (satellite data is still quite a bit more expensive than you think, especially with many stations)

I can pay $10 to have internet for the entire flight. Reasonably low bandwidth of course, but if I can splurge $10, the airline can.

Re: Preliminary report into Air India crash released

#495

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?

Engine fire requires you to cut fuel to the affected engine.

Pretty sure nearly all runbooks have you first move the thrust lever to idle before cutting off fuel. That suggests you shouldn't be able to cut fuel independently of the throttle.

Re: Preliminary report into Air India crash released

#496
post #19

Earlier quoted context omitted.

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

I imagine it would be more difficult to fly into terrain without a cooperative co pilot than cutting the fuel just after take off.

Re: Preliminary report into Air India crash released

#497
post #72

it makes sense to me that the pilot who said "I did not do it" actually did do it without realizing it, was supposed to be putting the landing gear up when he committed a muscle memory mistake. it happened around the time the landing gear should be up, and this explanation matches what was said in the cockpit, and the fact that the landing gear wasn't retracted. I think this idea was even floated initially by the you…

> it makes sense to me that..

This is exactly how the investigations are NOT conducted. You don't find the evidence that confirms your theory and call it a day when the pieces sorta fit together. You look solely at the evidence and listen to what they tell you leaving aside what you think could have happened.

Re: Preliminary report into Air India crash released

#498

Earlier quoted context omitted.

The timing is really curious. 08:08:35 Vr 08:08:39 Liftoff 08:08:42 Engine 1 cut-off 08:08:42 Engine 2 cut-off 08:08:47 minimum idel speed reached ?? One pilot to other: why cut-off. Other: Did not do it 08:08:52 Engine 1 run 08:08:52 Engine 2 run 1 second to switch them both off and then 4 seconds to switch them both on. No one admitted to switch them off. They are probably going with fine comb over the audio and al…

> Looks like the engines react very quickly to cut-off so it is not clear whether the question about the cut-off is prompted by a glance to the switches or the feel of the airplane. The workload is pretty high during the takeoff phase. The engines react right away when fuel flow is stopped. The engine displays can have some lag before data is updated. Relighting an engine at low speed is not feasible - most need 230-…

> I would assume the captain

The report states the FO was pilot flying.

Re: Preliminary report into Air India crash released

#499
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?

You can't yet - what we have is this sentence from the report: "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."

It's not a direct quote or transcript, it's reported speech.

Re: Preliminary report into Air India crash released

#500

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…

I'm not disagreeing with you I think this was manually done

But here's the thing a "near zero chance" when we are talking about an actual event changes the math

Maybe there's a combination of vibration and manufacturing defect or assembly fault or "hammer this until it works" that can cause the switches to flip. Very unlikely? Yes. Still close to 0% but much more likely in the scenario of an accident

Of course AAIB/NTSB etc didn't have any time to investigate the mechanical aspects of this failure

So yeah it was probably done intentionally but the "switches turning off by themselves" should not be excluded

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