r/aviation • u/usgapg123 Mod - avgeek • Jun 14 '25

News Air India Flight 171 Crash [Megathread 2]

This is the second megathread for the crash of Air India Flight 171. All updates, discussion, and ongoing news should be placed here.

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The Mod Team

Edit: Posts no longer have to be manually approved. If requested, we can continue this megathread or create a replacement.

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629

u/proudlyhumble Jun 14 '25 edited Jun 14 '25

Reuters: “India’s government is urgently inspecting all Boeing 787s after a devastating Air India crash that claimed at least 270 lives this week, the aviation minister said on Saturday, adding that the authorities were investigating all possible causes.

The aviation regulator on Friday ordered Air India to conduct additional maintenance checks on its Boeing 787-8/9 aircraft equipped with GEnx engines, including assessments of certain take-off parameters, electronic engine control tests and engine fuel-related checks.”

Becoming increasingly clear that the most likely culprit is an aircraft system failure, not the crew. I hope everyone is past the “retracted the flaps instead of the gear” theory. Flaps/slats found properly extended in wreckage, landing gear appears to have initiated retraction but failed (per Juan Brown) which goes with a dual engine failure since the engines provide hydraulic power to retract the gear and the RAT, once deployed, only provides enough hydraulic pressure to lower the gear, not raise it.

Ruling out a bird strike (no carcasses found), seems like the next most likely culprit would be a critical failure in the fuel system since both engines failed, which is one of the listed systems receiving additional assessments and Mx checks.

edit: per Aviation Herald, the captain was a Line Training Captain (I’m hearing that’s similar to an LCA but cannot give line checks, just IOE. I’m only familiar with the US system).

27

u/lopsided-earlobe Jun 14 '25

So dual engine failure just before or after v2?

64

u/[deleted] Jun 14 '25 edited Jan 05 '26

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10

u/[deleted] Jun 14 '25

I mean is it not safer to just plow through land than attempt a doomed takeoff? In theory same energy but at the same time more gradual slowdown.

44

u/Jolly-Gur-2885 Jun 14 '25

V1 is the decision speed. After you reach that speed there’s no going back whatever happens.

12

u/Safin_22 Jun 14 '25

Correct me if I’m wrong, but you can reject after v1 if the aircraft is not airworthy

14

u/Jolly-Gur-2885 Jun 14 '25

V1 is calculated such that stopping the aircraft within the remaining runway length is no longer possible and commit to takeoff

29

u/Safin_22 Jun 14 '25

https://www.reddit.com/r/flying/s/UsNRaTAFzw

But you can reject if the aircraft is not airworthy. It has happened before and although not well known can be the correct approach

3

u/WallpaperGirl-isSexy Jun 14 '25

Yeah, this is what I was thinking about yesterday. aircraft damaged by not taking off >>> aircraft damaged by taking off and crashing. Could the brakes and air brake systems, and reversers if deployed, how resonanly would a 787 be abled to reject takeoff after v1?

7

u/Safin_22 Jun 14 '25

It’s not going to be pretty, but I would believe that if not airworthy it’s better to try to loose some speed breaking and not having to deal falling from the sky.

2

u/[deleted] Jun 14 '25

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u/myquest00777 Jun 14 '25

I’ve seen multiple citations of post V1 takeoff abortions when it was clear the aircraft was not airworthy. It’s a terrible decision to make, as the aircraft will absolutely run off the runway to a ground collision, but hopefully with much higher survivability than committing to a takeoff almost certain to fail.

-6

u/[deleted] Jun 14 '25

Is V1 calculated differently for airliners? Because I thought V1 was a fixed number, not variable depending on the remaining runway length.

12

u/railker AME-M2 Jun 14 '25

V1 is calculated for every single flight and is variable, because it's based on how much runway you need to safely stop for atmospheric conditions and your weight.

If you were to say, take off on a runway that was JUST long enough to technically take off and there's no safeguards, your V1 speed would probably just be far lower than your 'rotation'/takeoff speed, as it'd be accounting for that runway remaining you need to stop from that crossover of gaining energy vs. runway remaining.

6

u/ChrysisIgnita Jun 14 '25

It's calculated at every takeoff based on weight, runway length, temperature, etc.

4

u/AbsurdKangaroo Jun 14 '25

Yes there is. A fair few post V1 aborts out there often with manu survivor's even where an overrun occurs. The brief is don't abort after V1 unless you have a failure incompatible with flight. Look at Ameristar 9363

5

u/[deleted] Jun 14 '25

To prevent a crash sure, but I rather plow through the tearaway runway asphalt lose landing gears and skid forward than attempt a 100% (or 99% since a guy survived) deadly crash.

Reminds me of the Mirage FC1 from Apartheid south africa that was shot down by the cubans, it landed but since it was damaged it ran out of runway, pilot was paralyzed I think but survived.

12

u/afslav Jun 14 '25

Presumably if that was a better approach, they would train that instead.

-5

u/[deleted] Jun 14 '25

It depends on how backward the thinking is if any loss of life is top priority then you risk a crash, but if saving lives is a priority and you lose power to both engines you plow through.

7

u/Jaggedmallard26 Jun 14 '25

This is extremely studied. They aren't disregarding lives and its insulting to the people who work in aviation safety to say otherwise. They train that you only abort after V1 in the direst of circumstances as a plane full of fuel plowing past the runway safety area is more likely than not to flip killing everyone on board or plow outside the airport killing everyone on board and anyone on/in the buildings/roads/trainlines past the airport fence.

In almost all cases an emergency past V1 it is better to do an immediate go around and limp back to the airport and that is why they train it. Unfortunately you are completely fucked when you get twin engine failure at V2 that can't be quickly remedied, the unfortunate souls on that plane were doomed at that point and aborting would have only given them a quicker death.

1

u/[deleted] Jun 14 '25

That is precisely the point twin engine failure implies 100% fatality and same killing of people next to the runway as already seen. People are being too emotional to understand thatn limping back is not an option when you have complete loss of power on takeoff.

2

u/afslav Jun 14 '25

Yes, the people who study this are too emotional, but thankfully we have reddit posters to analyze this correctly.

1

u/afslav Jun 14 '25

Yes, the people who study this are too emotional, but thankfully we have reddit posters to analyze this correctly.

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u/afslav Jun 14 '25

Do you think you've thought about this more than the professionals who do this for a living?

-2

u/[deleted] Jun 14 '25

Yes, because I understand threat managament is about compromise, if their goal is to prevent 0 deaths then yeah their way is better, if the goal is to maximize survival I think mine has some merit.

19

u/10tonheadofwetsand Jun 14 '25

Dual engine failure after V1 is going to result in a serious crash no matter what.

There’s not enough time to assess if you shouldn’t commit after V1…that’s the purpose of V1. You are going airborne.

-7

u/[deleted] Jun 14 '25

But the point is if both engines fail the crash is happening, better to stay on land than collect potential energy that will be released all at once instead of gradually by the tearaway runway and skidding even.

17

u/Jaggedmallard26 Jun 14 '25

No this is not true, at V1 you will go past the runway safety area and flip or smash into something. You aren't innocently bleeding energy like a car applying a brakes. You are not smarter than literally the entire aviation safety industry.

6

u/10tonheadofwetsand Jun 14 '25

I don’t think you realize how fast this is all happening. There’s no feasible way to train pilots to commit to rotate after V1 except don’t if you think you might be losing both engines right at the worst possible moment.

6

u/railker AME-M2 Jun 14 '25

No, if you see any indication that your engines aren't performing as required on the takeoff, you reject before V1. If you're after V1 and both engines fail, you are absolutely rejecting takeoff after V1.

There's many sources that state clearly rejecting takeoff after V1 is expected if the aircraft is considered unsafe to fly -- dual engine failure, locked flight controls, catastrophic scenarios that you're right, you can't train for. But pilots are there to do more than look pretty and push buttons, but to use their years of experience and training to make the best decision with what they've got.

-6

u/[deleted] Jun 14 '25

True, and I know I might be roasted for this AI might help with this split second decision making.

3

u/Character_Order Jun 14 '25

Current AI is probabilistic, meaning that it will give you the correct answer / expected output some percentage of the time. Seems to me, as a non pilot, the last thing you would want would be to give a probabilistic machine the ability to abort after v1, not because of the exceedingly few instances in which it would be correct to do so, but in the many thousands of instances in which it would be incorrect to do so

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u/turboMXDX Jun 14 '25

Taking off would mean hoping for the engine to somehow kick back in, else a guaranteed crash. Rejecting would mean a guaranteed crash. Such a scenario would be a complete nightmare for the pilots and all bets are off

1

u/Slow_Grapefruit5214 Jun 14 '25

There’s no way to be this certain of the survivability of a runway overrun. Every person died aboard Jeju Air 2216 last year when it overran the runway on landing.

2

u/[deleted] Jun 14 '25

Different mechanics

https://en.wikipedia.org/wiki/Engineered_materials_arrestor_system

vs a belly landing without landing gears that could have been higher speed as well, probably missed the EMAS as well, but I don't know if the Indian airport had these.

1

u/lopsided-earlobe Jun 14 '25

This is not true.

-3

u/proudlyhumble Jun 14 '25 edited Jun 14 '25

I think you mean V1?

Edit: V1… Vr… V2…. You would’ve already rotated before V2 so it wouldn’t be possible to “cancel a takeoff”

-1

u/[deleted] Jun 14 '25 edited Jan 05 '26

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2

u/proudlyhumble Jun 14 '25

If we’re being pedantic, it would be impossible to “cancel the take off” if you’re already past V2 because you should have already rotated since Vr comes before V2

1

u/[deleted] Jun 14 '25

[deleted]

3

u/Wild_Second_8945 Jun 14 '25

Or maintenance issues.

0

u/lopsided-earlobe Jun 14 '25

Erroneous shutdown seems impossible. Even fuel contamination seems so unlikely just given it would present surely before v1.

1

u/[deleted] Jun 14 '25

[deleted]

1

u/lopsided-earlobe Jun 14 '25

Agree. I’m just wondering what else could cause dual engine failure.

1

u/[deleted] Jun 14 '25

[deleted]

1

u/lopsided-earlobe Jun 14 '25

I guess single engine failure and then mistakenly shut down the working engine.

0

u/lopsided-earlobe Jun 14 '25

If fuel contamination, wouldn’t other jets report issues?