Preliminary report into Air India crash released • Hacker News Board

Re: Preliminary report into Air India crash released

#471

Post by potamic » Sat, Jul 12, 2025, 10:23 AM UTC

nottorp wrote: post #408

Almost 400 comments and no avherald link for reference? https://avherald.com/h?article=528f27ec

> On Jul 12th 2025 (UTC) India's media report that the investigation is NOT focussing on a human action causing the fuel switches to appear in the CUTOFF position, but on a system failure. 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. The stated MN4 computer with faulty soldering, that might weaken and lose contact due to the thermal stress after a number of cycles, interprets data and commands fuel metering valves - with the lost contact attaching the MN4 processor to the EEC intermittent electrical contact, loss of signal processing and engine control faults can occur. The SB writes under conditions for the SB: "An LOTC (Loss Of Thrust Control) event has occurred due to an EEC MN4 microprocessor solder ball failure." According to discussions in the industry it may be possible with the number of cycles VT-ANB had already completed, the solder balls were weakened sufficiently to detach the MN4 from the EEC momentarily due to loads during the takeoff rotation leading to the loss of control of thrust and shut down of the engines.

Still quite early in the investigation, and so many things to consider. I don't know why online communities have been so quick to gravitate towards the murder/suicide theory. I thought aviation enthusiasts of all people would want to keep an open mind until every other possibility is ruled out, however minuscule it might seem.

Re: Preliminary report into Air India crash released

#472

Post by fosk » Sat, Jul 12, 2025, 10:24 AM UTC

Jtsummers wrote: post #39

breadwinner wrote: post #37

Earlier quoted context omitted.

> post-flight muscle memory (of shutting off the engines) kicked in Possible, and if so it is too early to conclude it was murder-suicide. See also: https://www.thehindu.com/news/national/dgca-slaps-80-lakh-fi...

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.

0.1% of airline pilots fly intoxicated, and probably many more fly hangover which is an undetectable condition.

There is speculation that in the Air France flight 447 that crashed into the ocean en route to Paris, one or the pilots only had 1h of rest because of partying the night before. Of course it’s all speculative, and however unlikely it is, eventually it’s bound to happen that we get pilots with poor mental clarity in charge of large Boeings with hundreds of lives on board. Unfortunately it only takes one lapse of judgement to compromise the flight profile of a large airliner, even if corrected after a few seconds.

https://generalaviationnews.com/2014/11/06/vanity-fair-the-h...

Re: Preliminary report into Air India crash released

#473

Post by chgs » Sat, Jul 12, 2025, 10:28 AM UTC

mjevans wrote: post #305

noduerme wrote: post #243

Earlier quoted context omitted.

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.

Many systems log samples at an intervale of one sample per second. I could easily envision a transition event where a bump or brush of something sufficiently toggles one switch and then a fraction of a second later the other.

If the time was :11 and :12 there’s between 0.01 and 2 seconds between. If they were both at :11 then it’s between 0.01 and 1 second.

Re: Preliminary report into Air India crash released

#474

Post by [deleted] » Sat, Jul 12, 2025, 10:34 AM UTC

maxbond wrote: post #295

I just want to call out that, whatever the facts of this case, pilot heroism is way more common than pilot murder. This is off the top of my head, so don't quote me on the precise details, I'm probably misremembering some things. But a few of my favorite examples: - British Airways 5390: An incorrect repair causes the windshield of a plane to be blown out mid flight. A pilot is nearly sucked out. The head flight atte…

[deleted]

Re: Preliminary report into Air India crash released

#475

Post by raphman » Sat, Jul 12, 2025, 10:35 AM UTC

sandspar wrote: post #238

cosmicgadget wrote: post #43

Earlier quoted context omitted.

Is it easy to inadvertantly move both switches in such a scenario?

The switches are spring-loaded, notched in place, and have a rubber knob on the top. A pilot must squeeze the knob, remove the switch from its ON notch, press the switch, click it into the OFF notch, then release the knob. Doing it accidentally is impossible.

Here's also a video showing operation of the switches: https://www.youtube.com/watch?v=33hG9-BCJVQ

Re: Preliminary report into Air India crash released

#476

Post by azan_ » Sat, Jul 12, 2025, 10:39 AM UTC

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.

People do irrational things, especially if they are mentally unwell - https://en.wikipedia.org/wiki/Germanwings_Flight_9525

Re: Preliminary report into Air India crash released

#477

Post by bestouff » Sat, Jul 12, 2025, 10:40 AM UTC

dyauspitr wrote: post #162

fsckboy wrote: 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…

If you shut off the engines a couple of dozen meters above ground shouldn’t every alarm be blaring or there should be some sort of additional lever you have to pull way out of the way to enable shutting off the engine that close to the ground.

On an Airbus yes, engines won't stop if the thrust lever isn't on "idle".

Not so much on a Boeing.

Re: Preliminary report into Air India crash released

#478

Post by bestouff » Sat, Jul 12, 2025, 10:42 AM UTC

potamic wrote: post #471

nottorp wrote: post #408

Almost 400 comments and no avherald link for reference? https://avherald.com/h?article=528f27ec

> On Jul 12th 2025 (UTC) India's media report that the investigation is NOT focussing on a human action causing the fuel switches to appear in the CUTOFF position, but on a system failure. 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…

Kneejerk patriotic reaction ?

Re: Preliminary report into Air India crash released

#479

Post by raphman » Sat, Jul 12, 2025, 10:44 AM UTC

cypherpunks01 wrote: post #444

JSteph22 wrote: post #410

Earlier quoted context omitted.

>mental fog, cognitive overload, wrong muscle memor Agreed. The sequence of events also supports this. I believe one of the pilots made a terrible muscle memory mistake and cutoff the fuel instead of raising the landing gear. This would explain why the landing gear was never raised, why the pilot who was accused of cutting off the fuel denied it (in his mind he had only retracted the landing gear) and why the engines…

Were the landing gear switches and fuel cutoff switches pretty close to each other here?

Not really. Landing gear switches are above the throttle between the screens¹, fuel cutoff switches are below it².

¹) https://youtu.be/RbmFmWqqq0c?t=19

²) https://youtu.be/33hG9-BCJVQ?t=5

(I'm not an expert, I just watched these videos)

Re: Preliminary report into Air India crash released

#480

Post by nosianu » Sat, Jul 12, 2025, 10:46 AM UTC

xlbuttplug2 wrote: post #401

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?

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 them much more time - about 3.5 minutes of glide time, vs. 32 seconds in the air, total, for the Air India flight.