Preliminary report into Air India crash released • Hacker News Board

Re: Preliminary report into Air India crash released

#311

Post by lxgr » Sat, Jul 12, 2025, 5:07 AM UTC

p1mrx wrote: post #217

pixl97 wrote: post #142

Earlier quoted context omitted.

When your engine catches on fire/blows apart on takeoff you want to cut fuel as fast as possible.

Proposed algorithm: If the flight computer thinks the engine looks "normal", then blare an alarm for x seconds before cutting the fuel. I wonder if there have been cases where a pilot had to cut fuel before the computer could detect anything abnormal? I do realize that defining "abnormal" is the hardest part of this algorithm.

If the computer could tell perfectly whether the engine “looks normal” or not, there wouldn’t be any need for a switch. If it can’t, the switch most likely needs to work without delay in at least some situations.

In safety-critical engineering, you generally either automate things fully (i.e. to exceed human capabilities in all situations, not just most), or you keep them manual. Half-measures of automation kill people.

Re: Preliminary report into Air India crash released

#312

Post by abracadaniel » Sat, Jul 12, 2025, 5:07 AM UTC

mcpeepants wrote: post #252

adrianmonk wrote: post #222

Earlier quoted context omitted.

I don't think the theory is that the muscle memory sequences resemble each other. Instead, it's that because muscle memory allows you to do things without thinking about it, you can get mixed up about which action you meant to perform and go through the whole process without realizing it.

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.

Re: Preliminary report into Air India crash released

#313

Post by ExoticPearTree » Sat, Jul 12, 2025, 5:09 AM UTC

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…

> And both pilots deny doing it. > It's difficult to conclude anything other than murder-suicide.

You’re trying to prove a negative here.

I am not familiar with the 787 operations, but there are a few issues that need to be sorted out first: - altitude when pilots start the after takeoff checklist

- if there are any other switches that are operated in tandem in the general vicinity of where the engine cutoff switches are

- if the cutoff switches had the locking mechanisms present, and if not, if they could be moved inadvertently by the pilot flying hand

Discarding other possibilities in an investigation can have adverse consequences.

Did you ever always push the right buttons every time?

Re: Preliminary report into Air India crash released

#314

Post by ssivark » Sat, Jul 12, 2025, 5:16 AM UTC

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…

> So the fuel supply was cut off intentionally. The switches in question are also built so they cannot be triggered accidentally

FAA issued a Special Airworthiness Information Bulletin SAIB NM-18-33 in 2018 warning that on several Boeing models including the 787 the locking mechanism of the fuel switches could be inoperative.

https://www.aviacionline.com/recommended-versus-mandatory-th...

Per FAA the checks were recommended but not mandatory.

Re: Preliminary report into Air India crash released

#315

Post by moralestapia » Sat, Jul 12, 2025, 5:17 AM UTC

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.

This kind of attitude gets innocent people behind bars for life. Disgusting.

It's difficult to conclude anything until the investigation is finished and I hope the ones who are carrying it out are as levelheaded, neutral and professional as possible.

Re: Preliminary report into Air India crash released

#316

Post by michaelmrose » Sat, Jul 12, 2025, 5:22 AM UTC

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…

Given the recent boundless incompetence by Boeing why not ask if their is any way for such to fail out of scope of the normal interface?

Re: Preliminary report into Air India crash released

#317

Post by card_zero » Sat, Jul 12, 2025, 5:22 AM UTC

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…

Cutting the engines within seconds of leaving the ground doesn't fit suicide very well. I'd expect something more like flying into the side of a mountain or heading really far out into the Indian ocean until you vanish from radar and cause a big mystery.

For instance, you might deliberately kill yourself by driving your car really fast into something solid, but you probably wouldn't try to do that while backing out of the garage.

Re: Preliminary report into Air India crash released

#318

Post by moralestapia » Sat, Jul 12, 2025, 5:25 AM UTC

alphabettsy wrote: post #58

Jtsummers wrote: post #39

Earlier quoted context omitted.

The report shows 0 flight hours during the prior 24 hours for both pilots, and 7 hours and 6 hours each for the previous 7 days. It seems they were both fresh pilots for this flight.

that doesn’t tell us they were fresh. Only that they hadn’t flown. They could’ve slept 0 hours before or any number of things.

Sure, and aliens could also be involved.

However, the only relevant evidence that exists suggests they had enough rest. You don't build verdicts on suppositions, you build them on proven facts.

This does not guarantee you will reach the truth, but it's miles better than admitting every baseless hypothesis that comes up.

Re: Preliminary report into Air India crash released

#319

Post by ExoticPearTree » Sat, Jul 12, 2025, 5:29 AM UTC

yardstick wrote: post #176

Waterluvian wrote: post #152

Earlier quoted context omitted.

Not that humans are known to behave rationally when trying to commit suicide, but it’s interesting that the switches were re-engaged successfully without protest or a fight. It’s just an interesting detail to wonder about.

The reasoning I’ve heard is: it didn’t matter anymore, the damage was already done and there was no way any attempts at recovering from it would have been successful.

There would have been an inaction on the part of the pilot that did this, but it is not mentioned in the CVR transcript.

Hard to believe the other pilot wouldn’t have said anything.

Recovering the airplane and have some people survive the crash are two very different things.

Re: Preliminary report into Air India crash released

#320

Post by burnt-resistor » Sat, Jul 12, 2025, 5:30 AM UTC

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.

Bad analogy because pilots are trained and rehearse and practice memory items until they are instinctual.

> impossible by design.

Deflecting that the human is the weakest part of the system. One or other may have panicked and made a mistake, made a mistake unintentionally, went crazy and doomed the flight, or intentionally doomed the flight for some socioeconomic reasons. These are speculative possibilities that we don't know yet, and may never know; we only know what has definitely happened from the evidence per the investigation. It's standing way out over one's feet to declare from an armchair that it was "definitely" X or Y before the investigation is complete.