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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

#671

Post by sgt101 »

jon_smark wrote: post #484
sgt101 wrote: post #462

Earlier quoted context omitted.

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.

For a long time my wife refused to accept that Tree Kangaroos existed and insisted that I'd made them up. When the internet came along she looked them up and treated me strangely for a while.

What things that you have never seen do you not believe in?

Re: Preliminary report into Air India crash released

#672

Post by yason »

It is known that the switches cannot effectively be flipped by accident.

It is known that the switches were set to "cut-off" because they were then later restored to "run", so it was not an electrical fault (i.e. switches pointing to run but reporting cut-off).

Pilot dialogue and engine telemetry confirms the cause of power loss was fuel cut-off.

The question I can't help but think is how did the pilot realize it was the cut-off switches?

I'm sure there's a warning message for them somewhere but in the few seconds of time when you're losing thrust right after rotate, and you're bombarded by a lot of warnings and errors on the screen and in the speakers: how likely are you to notice the fuel cut-off switches have been flipped?

Those switches are something you never, ever think about during operation because you're trained to only operate them when starting up and parking (and yes, in an emergency where you need to shut down the engine quick).

How long would it take for an average pilot to realize it's not one of the dozens of memory items pointing to more likely scenarios causing loss of thrust, ones that they've been training to check in case of an imminent emergency? And why didn't the first pilot who was recorded to notice the fuel cut-off didn't immediately flip the switches to "run" position first instead of asking the other pilot about it?

Re: Preliminary report into Air India crash released

#673

Post by mnahkies »

ninkendo wrote: post #646
cjbprime wrote: post #457

Earlier quoted context omitted.

Now I'm trying to remember if I've ever picked up my razor and accidentally begun tooth brushing motions with it. Probably! More relevantly, you seem to me to be unduly confident about what this pilot's associative triggers might and might not be.

I've definitely put shaving cream on my toothbrush before.

Not a bathroom one, but the number of times I've tried to pay for public transport with my work/office fob is mental. Generally happens on days where I'm feeling sharper than average but also consumed with problem solving

Re: Preliminary report into Air India crash released

#674

Post by xlbuttplug2 »

nosianu wrote: post #480
xlbuttplug2 wrote: post #401

Earlier quoted context omitted.

I'm assuming fuel being cut off is salvageable if not in the middle of a densely populated city, especially if above a plain or water. So it could be the favorable option in case of an engine fire. Also, such complexity would introduce additional points of failure - as a sister comment mentions, a faulty altimeter (or whatever sensor) could prevent you from cutting off fuel when you need to.

> if not in the middle of a densely populated city, especially if above a plain or water What is on the ground below does not matter at that point - how far above that ground you are is what is important. More altitude is more time. This flight was less than 200 meters up in the air. Sully's flight that you probably remember, that made a successful emergency landing on the river, was about 860 meters high, giving the…

Okay, maybe there is little hope of making an ideal landing. But the likelihood of it being a fatal accident is significantly reduced without the building in the equation, no?

Re: Preliminary report into Air India crash released

#675

Post by interestica »

WalterBright wrote: post #626
interestica wrote: post #572

Earlier quoted context omitted.

That’s absolutely applicable here. It means that an engine cutoff shouldn’t be allowed at all during certain parts of flight. It’s not crazy to think that a design fix would be to prevent those engagements during certain parts of takeoff (a certain window). It’s fly by wire anyway so it could presumably be done programmatically. MCAS was basically made to prevent user input that would send the plane into a dangerous…

> The computer overrode the inputs. This is incorrect. The manual stabilizer trim thumb switches override MCAS.

Are we not in agreement? MCAS overrode the inputs and the thumb switches could override MCAS?

Re: Preliminary report into Air India crash released

#676

Post by jeffbee »

MaKey wrote: post #583
jeffbee wrote: post #119

Earlier quoted context omitted.

Suggest a system that would prevent this, but only this, without causing other risks.

Another comment mentioned that with an Airbus you first have to move the thrust lever to idle before you're able to cutoff the fuel.

That seems sensible and relatively easy to implement without screwing it up.

Re: Preliminary report into Air India crash released

#677

Post by BurningFrog »

ExoticPearTree wrote: post #339
Spooky23 wrote: post #299

Earlier quoted context omitted.

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

To answer your question: because it is a very rare occurence.

All commercial plane crashes are very rare occurrences.

Re: Preliminary report into Air India crash released

#678

Post by JumpCrisscross »

ra7 wrote: post #300
JumpCrisscross wrote: post #293

Earlier quoted context omitted.

> This is ambiguous and could be read as "one hand, simultaneously" Not within the context of the thread.

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.

> Context is both these switches being turned off with a 1 second gap. Doing it with one hand simultaneously would possibly explain it

It would. So would switching both quickly in succession. One second is a long time—I can adjust power, prop, fuel pump and flaps in about that time.

Re: Preliminary report into Air India crash released

#680

Post by hackrmn »

yason wrote: post #672

It is known that the switches cannot effectively be flipped by accident. It is known that the switches were set to "cut-off" because they were then later restored to "run", so it was not an electrical fault (i.e. switches pointing to run but reporting cut-off). Pilot dialogue and engine telemetry confirms the cause of power loss was fuel cut-off. The question I can't help but think is how did the pilot realize it was…

Given what you're vaguely implying -- that the switches would be nowhere near the first thing a pilot would normally think of in the kind of situation -- what are the odds the pilot asking on record "did you flip the fuel cut-off switch?" is the one who actually flipped the switches and was simply trying to fool the would-be investigation (even knowing they all are about to perish)?
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