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Baffling tragedy, again. Clear skies, no LiveATC but reports of single Mayday call, gear out but no flaps and no control inputs visible in the grainy video. So

Baffling tragedy, again. Clear skies, no LiveATC but reports of single Mayday call, gear out but no flaps and no control inputs visible in the grainy video. Something has to go really catastrophically wrong with a modern jetliner for that to happen, like the very dense flock of birds in Korea with the 737 a couple of months back. The very short intersection takeoff seems like a good hint (and terrible practice), but all gears and engines look kinda OK from the outside. If they‘d scraped something on takeoff hard enough to take out both engines, there’d probably be some visible damage, or at least some gears sheared off. EDIT: Fully agree with the speculation in light of tragedy comments, but aviation is a bit of a special case. The reason it’s so safe is because an awful lot of people immediately start looking into potential reasons and then spend years getting to the bottom of it. The initial speculation is like an exercise: what could have happened? What if I’m in that situation, and need to act now, without knowing much of anything? If you do that a couple of dozen or hundred times throughout your life, it really builds a foundation for when an actual emergency ever happens to you. It’s a bit like the reason most flight attendants in the emergency exit jump seat across from you won’t talk with you during the actual takeoff and landing: they‘re mentally walking through a potential emergency and what they‘d then need to do. Every single time. So if it ever happens, there‘s muscle memory, 10000x over. EDIT 2: see the Flightradar24 comment below, it looks like they did backtrack and use the full runway.

dist-epoch 1y ago
A pilot speculated that it looks like a multiple bird strike.
- xattt 1y ago
  Why no control inputs then? Surely, the plane could still be commanded in absence of engine power.
  - cm2187 1y ago
    But also how long after take off do you retract the flaps? Can it be a pilot error (took off without flaps?). It happened more than once in the past, though I thought a modern plane like the dreamliner would make that mistake nearly impossible.
  - fabian2k 1y ago
    I don't really know enough about this, but what would you expect the pilots to do with that control if they don't have any thrust? Unless there was a suitable landing spot very, very close I don't see what they could do even if they have full control of the plane. There is nothing they can do except getting the engines to work to avoid a crash, the only thing controls would give them is the option to choose a slightly different place to crash.
  - Arch-TK 1y ago
    The engines power the hydraulic actuators in an aircraft an aircraft of that size cannot be trivially controlled without that hydraulic system. The APU should have been started to provide backup power in the case of engine failure but during take-off there is already very little time to do anything and it's possible that the sudden workload overloaded both the pilot and copilot or some other human factors were involved. That being said, in the video I saw, the aircraft was already going too slow to realistically recover. And all you would get at that point is just an extended duration of glide which at best would let you find a less populated area to crash into.
    - consumer451 1y ago
      You can hear what sounds a lot like the very distinct sound of the RAT having been deployed in one of the videos. There is also no main turbine sound. This really seems like dual engine failure, for whatever reason. https://old.reddit.com/r/ahmedabad/comments/1l9i1ga/om_shanti_to_everyone/?share_id=FWeAcxJDXum67xe83WaA9 https://old.reddit.com/r/ahmedabad/comments/1l9i1ga/om_shant... https://en.wikipedia.org/wiki/Ram_air_turbine https://en.wikipedia.org/wiki/Ram_air_turbine
      - Arch-TK 1y ago
        I saw you mentioning this but the RAT on the 787 sticks out of the bottom and should have been visible at around :04 seconds into that video when the aircraft silhouette is visible clearly against the background. Although it's possible I am just missing from the video. You are right that the sound is quite distinct and can be clearly heard in the video.
        consumer451 1y ago
        The RAT is surprising tiny on the 787, and this is a phone video of a monitor, then run through Reddit compression. I am of course not 100% sure about any of this. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ95qKjo2w-eWEKSE-iYN-PRERIvBdr7A6sxA&s https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ95qKj... edit: here you might possibly see it on the right, a very tiny blurry thing https://imgur.com/a/CElWKzQ https://imgur.com/a/CElWKzQ source: https://old.reddit.com/r/aviation/comments/1l9hqzp/air_india_flight_171_crash/mxcn99k/ https://old.reddit.com/r/aviation/comments/1l9hqzp/air_india...
  - tim333 1y ago
    What would you do with the controls? There wasn't an alternative landing area they could have got to. About all they could probably do was to try to get the engines going.
greybox 1y ago
What do you mean by "(and terrible practice)"?
- brunohaid 1y ago
  „Runway behind you“ is drilled into your head as one of the useless things in aviation. You always want to make sure to use the most runway available to you, exactly for cases when something happens. Hypothetical in this case: you realize something’s wrong with the plane, but you’re already too fast and close to the end of the runway to reject the takeoff because you wouldn’t be able to stop in time anymore. Large airports with heavy traffic sometimes have operational constraints to send a plane out ahead of another from some intersection, but if the ADSB data is correct, taking off from half the available runway in a fully loaded 787 isn’t a good idea. You just give up a ton of margin for errors.
- FridayoLeary 1y ago
  it means using less then the full length of runaway available. I'm not a pilot but i'm guessing that it's not good because it adds an unnecessary potential complication to the take off.
- Arch-TK 1y ago
  An intersection takeoff is a takeoff where you do not use the full length of the runway. When you are a large aeroplane with a full load, reaching the necessary takeoff speeds required to rotate (pull up and begin lifting from the ground) can take longer than normal, at which point the climb speed will also be reduced if not properly compensated for (e.g. you miscalculate something and set the wrong elevator trim/takeoff thrust/something else). When you are taking off, you have a short portion of the runway which you can use to abort the takeoff depending on failures, but that portion can become even shorter depending on the length of the runway. Usually the first part of takeoff you would abort for almost any reason, and the second part you would only abort in a serious emergency, once you reach a certain point you simply cannot afford to abort because you will not stop in time to crash into whatever is at the end of the runway at which point you must take-off even if you are going to immediately request an emergency landing afterwards. So if you are heavily loaded, with a lot of people on board, and you do an intersection takeoff, you are taking a risk that if you made a mistake or something goes wrong you will not have the ability to safely recover. That's why it's a terrible practice in this case. All it does is save a little bit of time which would be spent taxiing to the actual start of the runway.
pncnmnp 1y ago
Regarding the intersection takeoff, Flightradar24 just tweeted this: > We are continuing to process data from receiver sources individually. Additional processing confirms #AI171 departed using the full length of Runway 23 at Ahmedabad. RWY 23 is 11,499 feet long. The aircraft backtracked to the end of the runway before beginning its take off roll. https://x.com/flightradar24/status/1933138841214611760 https://x.com/flightradar24/status/1933138841214611760
- james_pm 1y ago
  FR24 is also on Bluesky: https://bsky.app/profile/flightradar24.com/post/3lrfwaqs2ls2v https://bsky.app/profile/flightradar24.com/post/3lrfwaqs2ls2...
epolanski 1y ago
> gear out That is normal and standard procedure if you're having issues lifting the plane, because retracting the gear means _increasing_ drag for a crucial 10/15 seconds as the doors open and thus slowing the plane further. > but no flaps and no control inputs visible Standard Dreamliner operating procedure, you take off at flaps 10 or 5, they are barely visible from the outside, see many random videos of 787s takeoffs on Youtube like this: https://www.youtube.com/shorts/Ld_zyEESazI https://www.youtube.com/shorts/Ld_zyEESazI
- brunohaid 1y ago
  True on both counts, was a quite early comment and initially thought they're coming back in to land vs barely having taken off. Only leaves control inputs but given how short the video is it could also be that there simply wasn't much to input/correct anymore despite the slight rocking. Can't edit anymore, but the general gist of catastrophic failure needed to prevent a 787 from climbing out of this situation still holds.
  - wat10000 1y ago
    I don't think you'd expect any control inputs in that scenario. They were level with a reasonable pitch angle. Aircraft attitude was fine, they just didn't have enough power to arrest the descent. Such a loss of power with a full load of fuel definitely indicates a swift catastrophic failure to the engines at least.
- FireBeyond 1y ago
  Very much so. Gear retraction should only happen if (generalizing here) you've established a "positive rate of climb".
- apple4ever 1y ago
  > That is normal and standard procedure if you're having issues lifting the plane, because retracting the gear means _increasing_ drag for a crucial 10/15 seconds as the doors open and thus slowing the plane further. Oh fascinating! I would not have considered that but it totally makes sense.

dist-epoch 1y ago

A pilot speculated that it looks like a multiple bird strike.

xattt 1y ago
Why no control inputs then? Surely, the plane could still be commanded in absence of engine power.
- cm2187 1y ago
  But also how long after take off do you retract the flaps? Can it be a pilot error (took off without flaps?). It happened more than once in the past, though I thought a modern plane like the dreamliner would make that mistake nearly impossible.
- fabian2k 1y ago
  I don't really know enough about this, but what would you expect the pilots to do with that control if they don't have any thrust? Unless there was a suitable landing spot very, very close I don't see what they could do even if they have full control of the plane. There is nothing they can do except getting the engines to work to avoid a crash, the only thing controls would give them is the option to choose a slightly different place to crash.
- Arch-TK 1y ago
  The engines power the hydraulic actuators in an aircraft an aircraft of that size cannot be trivially controlled without that hydraulic system. The APU should have been started to provide backup power in the case of engine failure but during take-off there is already very little time to do anything and it's possible that the sudden workload overloaded both the pilot and copilot or some other human factors were involved. That being said, in the video I saw, the aircraft was already going too slow to realistically recover. And all you would get at that point is just an extended duration of glide which at best would let you find a less populated area to crash into.
  - consumer451 1y ago
    You can hear what sounds a lot like the very distinct sound of the RAT having been deployed in one of the videos. There is also no main turbine sound. This really seems like dual engine failure, for whatever reason. https://old.reddit.com/r/ahmedabad/comments/1l9i1ga/om_shanti_to_everyone/?share_id=FWeAcxJDXum67xe83WaA9 https://old.reddit.com/r/ahmedabad/comments/1l9i1ga/om_shant... https://en.wikipedia.org/wiki/Ram_air_turbine https://en.wikipedia.org/wiki/Ram_air_turbine
    - Arch-TK 1y ago
      I saw you mentioning this but the RAT on the 787 sticks out of the bottom and should have been visible at around :04 seconds into that video when the aircraft silhouette is visible clearly against the background. Although it's possible I am just missing from the video. You are right that the sound is quite distinct and can be clearly heard in the video.
      - consumer451 1y ago
        The RAT is surprising tiny on the 787, and this is a phone video of a monitor, then run through Reddit compression. I am of course not 100% sure about any of this. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ95qKjo2w-eWEKSE-iYN-PRERIvBdr7A6sxA&s https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ95qKj... edit: here you might possibly see it on the right, a very tiny blurry thing https://imgur.com/a/CElWKzQ https://imgur.com/a/CElWKzQ source: https://old.reddit.com/r/aviation/comments/1l9hqzp/air_india_flight_171_crash/mxcn99k/ https://old.reddit.com/r/aviation/comments/1l9hqzp/air_india...
- tim333 1y ago
  What would you do with the controls? There wasn't an alternative landing area they could have got to. About all they could probably do was to try to get the engines going.

greybox 1y ago

What do you mean by "(and terrible practice)"?

brunohaid 1y ago
„Runway behind you“ is drilled into your head as one of the useless things in aviation. You always want to make sure to use the most runway available to you, exactly for cases when something happens. Hypothetical in this case: you realize something’s wrong with the plane, but you’re already too fast and close to the end of the runway to reject the takeoff because you wouldn’t be able to stop in time anymore. Large airports with heavy traffic sometimes have operational constraints to send a plane out ahead of another from some intersection, but if the ADSB data is correct, taking off from half the available runway in a fully loaded 787 isn’t a good idea. You just give up a ton of margin for errors.
FridayoLeary 1y ago
it means using less then the full length of runaway available. I'm not a pilot but i'm guessing that it's not good because it adds an unnecessary potential complication to the take off.
Arch-TK 1y ago
An intersection takeoff is a takeoff where you do not use the full length of the runway. When you are a large aeroplane with a full load, reaching the necessary takeoff speeds required to rotate (pull up and begin lifting from the ground) can take longer than normal, at which point the climb speed will also be reduced if not properly compensated for (e.g. you miscalculate something and set the wrong elevator trim/takeoff thrust/something else). When you are taking off, you have a short portion of the runway which you can use to abort the takeoff depending on failures, but that portion can become even shorter depending on the length of the runway. Usually the first part of takeoff you would abort for almost any reason, and the second part you would only abort in a serious emergency, once you reach a certain point you simply cannot afford to abort because you will not stop in time to crash into whatever is at the end of the runway at which point you must take-off even if you are going to immediately request an emergency landing afterwards. So if you are heavily loaded, with a lot of people on board, and you do an intersection takeoff, you are taking a risk that if you made a mistake or something goes wrong you will not have the ability to safely recover. That's why it's a terrible practice in this case. All it does is save a little bit of time which would be spent taxiing to the actual start of the runway.

pncnmnp 1y ago

Regarding the intersection takeoff, Flightradar24 just tweeted this: > We are continuing to process data from receiver sources individually. Additional processing confirms #AI171 departed using the full length of Runway 23 at Ahmedabad. RWY 23 is 11,499 feet long. The aircraft backtracked to the end of the runway before beginning its take off roll. https://x.com/flightradar24/status/1933138841214611760 https://x.com/flightradar24/status/1933138841214611760

james_pm 1y ago
FR24 is also on Bluesky: https://bsky.app/profile/flightradar24.com/post/3lrfwaqs2ls2v https://bsky.app/profile/flightradar24.com/post/3lrfwaqs2ls2...

epolanski 1y ago

> gear out That is normal and standard procedure if you're having issues lifting the plane, because retracting the gear means _increasing_ drag for a crucial 10/15 seconds as the doors open and thus slowing the plane further. > but no flaps and no control inputs visible Standard Dreamliner operating procedure, you take off at flaps 10 or 5, they are barely visible from the outside, see many random videos of 787s takeoffs on Youtube like this: https://www.youtube.com/shorts/Ld_zyEESazI https://www.youtube.com/shorts/Ld_zyEESazI

brunohaid 1y ago
True on both counts, was a quite early comment and initially thought they're coming back in to land vs barely having taken off. Only leaves control inputs but given how short the video is it could also be that there simply wasn't much to input/correct anymore despite the slight rocking. Can't edit anymore, but the general gist of catastrophic failure needed to prevent a 787 from climbing out of this situation still holds.
- wat10000 1y ago
  I don't think you'd expect any control inputs in that scenario. They were level with a reasonable pitch angle. Aircraft attitude was fine, they just didn't have enough power to arrest the descent. Such a loss of power with a full load of fuel definitely indicates a swift catastrophic failure to the engines at least.
FireBeyond 1y ago
Very much so. Gear retraction should only happen if (generalizing here) you've established a "positive rate of climb".
apple4ever 1y ago
> That is normal and standard procedure if you're having issues lifting the plane, because retracting the gear means _increasing_ drag for a crucial 10/15 seconds as the doors open and thus slowing the plane further. Oh fascinating! I would not have considered that but it totally makes sense.