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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

#771

Post by yuliyp »

mihaaly wrote: post #728
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…

How can it be known that the switches were moved physically and not some electrical signal occured on its own (fault) equivalent of switches operated, without actual physical moement of the switch? Some electronic fault in the line of the signal. I do not expect having an independent sensor for this switch monitoring actual physical movements of the switch in parallel of the intended fuel controlling signals occurrin…

We know that they restarted a few seconds later a few seconds apart from each other, and shut off a second part from each other.

It's extremely unlikely for a pilot to decide to react by shutting both switches off, then turning them on within seconds (this is not a failure mode they'd have expected, deciding to shut the engine off a couple hundred feet in the air would be... a fairly reckless decision).

That leaves both switches spontaneously turning off, then back on, a couple seconds after takeoff, which is a failure mode that's never been seen before once let alone twice. Also the pilots didn't make a statement about an incongruity between the report from the plane's systems about the switch being off vs the physical position, which they very likely would have in such a situation.

I think it's reasonable to rule that theory out.

Re: Preliminary report into Air India crash released

#773

Post by MangoToupe »

gamblor956 wrote: post #759
sillysaurusx wrote: post #701

Earlier quoted context omitted.

On the contrary: https://youtu.be/988j2-4CdgM?si=G39BwNy1zJEeUi2k The whole reason a pilot made that video is because there’s a huge problem in the airline industry right now.

On the contrary, that video actually supports the OP's claim. A pilot with a well-managed mental condition would be allowed to fly. So, a pilot with depression over the loss of a parent would still be allowed to fly. But a pilot with suicidal ideations, or taking hallucinogens, like Emerson from Alaska Airlines Flight 2509 (the flight discussed in the linked video), would not be allowed to fly. And that's exactly the…

Suicidal ideation is a normal part of being human. Fantasizing about committing suicide by crashing a plane is jot. Neither of these are remotely comparable to hallucinogens.

Re: Preliminary report into Air India crash released

#774

Post by userbinator »

shash wrote: post #503
userbinator wrote: post #454

Earlier quoted context omitted.

I'd suspect the wiring leading from the switches to the engine controllers first, especially since it looked like both circuits cut out nearly at the same time.

This is speculation again since I don't really know, but my understanding of aviation engineering is that there would be two separate controllers for each engine connected to these two switches. At no point would they be connected to the _same_ control unit. The really short time (~1s) between the two being cutoff is the difficult thing to explain here.

Are the wires leading up to those switches on the console also kept separate, or are they just bundled together as part of the same harness (presumably before it splits to go to the engines)? I think that's also important in understanding the possible failure modes.

Re: Preliminary report into Air India crash released

#775

Post by manquer »

sgerenser wrote: post #768
manquer wrote: post #720

Earlier quoted context omitted.

Given the fly by wire nature of 787 there is an also fourth option. The physical switch was not touched at all , and the software has a bug under some rare conditions which cut off the supply to both engines.

Extremely unlikely, since we can hear the other pilot ask why he turned the fuel switches. If it was an electrical glitch, he wouldn’t be able to see that they are in the cutoff position.

All we know is the pilot flying is only asking whether the pilot monitoring if he cut off

- We don't know if he meant the switch specifically at all. He could also have meant engines or thrust in general. There are many other visual signals and UX indicators to know if engines are spinning down. Thrust levels, to RPM to falling speed, change in angle of attack, rate of climb, even engine noise, vibrations you expect at full thrust etc.

- We also don't know if the switch was physically in cut off position in the first place or even if was the pilot noticed that specific visual signal and meant that when he spoke.

If it was a software issue, it is possible the switch was properly positioned, and software issue cut engine was cutoff, the display screens and other lights would show that.

In such a scenario, the pilot(s) would have likely checked with each other first if they did something as in the audio and manually tried restarting the engine as they seem to have done.

I am not saying it is a bug or any specific fault scenario, Just that it too early, we don't yet have enough information to say what is likely at all.

Re: Preliminary report into Air India crash released

#776

Post by dewarrn1 »

breadwinner wrote: post #638
SAI_Peregrinus wrote: post #629

Assuming this is a murder-suicide and not a mistake or malfunction somehow, it's very damning of the FAA's policy to revoke the pilot's licenses of anyone seeking treatment for mental health issues. This was in India and thus not FAA jurisdiction, but it still would be a case where an untreated mental health issue lead to hundreds of deaths. By making pilots choose between their careers & medical treatment (since the…

Wouldn't it be better to provide such pilots alternate career paths? That way they can still make a living and the traveling public is not placed under unnecessary risk.

A “dead airspace”, perhaps?

Re: Preliminary report into Air India crash released

#777

Post by Miner49er »

seydor wrote: post #392

So what's the status of full self driving airplanes (aka autopilot , or maybe autodriver to avoid the bad connotations)

Is it really desirable though? Sure, it might eliminate human error, but it also probably eliminate pilots saving planes. I don't think an autopilot would have put US Airways Flight 1549 into the Hudson.

Re: Preliminary report into Air India crash released

#779

Post by cryptonector »

DebtDeflation wrote: post #733
hackrmn wrote: post #680

Earlier quoted context omitted.

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)?

I'd say the odds are 50%. The odds of the opposite scenario - where the pilot who said "did you flip the fuel cutoff" wasn't the one who did it are also 50%. Based on the cutoffs for both engines being flipped 1 second apart, the above exchange being caught on the CVR, and then within 10 seconds the (presumably the other) pilot switching them back to Run, it's pretty clear that this was a deliberate act.

Reading https://news.ycombinator.com/item?id=44543536 I think we should not jump to conclusions yet.

Re: Preliminary report into Air India crash released

#780

Post by noqc »

histriosum wrote: post #699
noqc wrote: post #661

Earlier quoted context omitted.

The murder suicide angle isn't particularly worthy of assumption yet. Have you ever put your phone in the fridge? Pilots deactivate the fuel cutoff at the end of the final taxi to the gate. This makes flipping these switches a practiced maneuver , capable of being performed without conscious thought, regardless of whether they came with safety locks installed. Brain farts are a real phenomenon, and an accidental fuel…

> The report is actually a little cagey about whether the locks were properly installed on these switches. Said locks are supposedly optional. The locks/gates on the switches are definitely NOT optional. There was an SAIB about some switches that may have been installed improperly. It didn't result in an AD, which likely means the extent was limited or potentially even nil. The switches were moved to cutoff with a on…

> one second delay

did the report say a one second delay or that the two switches were turned off at consecutive seconds? The latter is what I remembered, but I'll check again.

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