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Captain Biggles 101
2025-06-13T08:07:00 permalink Post: 11900140 |
There isn't enough clarity on numerous issues, and without answers to the following, zero conclusions can be made as to a possible cause. This is definitely one that could go in numerous directions. Anyone claiming to have the definitive answers must have the FDR data, and I'm assuming that shouldn't take too long to be located and analysed.
1a. Were flaps deployed at start of take off roll? 1b. Were flaps retracted coinciding with climb rate reduction? 2. Did the RAT definitely deploy? The videos are grainy low quality. AI improvement surely isn't reliable. 3. If the RAT deployed, would that indicate complete power loss? 4. Was there any other audio indicating thrust loss or variations during departure? 5. Can we confirm the pilot Mayday indicating thrust loss? If so, that needs investigation as a first priority. The pilot was telling us the cause. Unless we have alternative information he should be believed. 6. Why was the gear not retracted? Distraction, hydraulic failure, flap instead of gear, intentionally, the possibilities are endless. 7. If complete thrust loss occurred, other than a severe fuel issue, what could cause simultaneous flameout? That would be almost unimaginable, yet this is what the pilot allergy said happened. It would have massive ramifications if that gets confirmed. I don't think the video clips we have are clear enough to say anything at all at this stage. Flaps are hard to see on 787 imo for departure settings. All I can say is it appeared to climb well in the first seconds, then coinciding with the point that gear would usually be retracted, lift appears to very quickly be lost. That indicates sudden speed loss, or lift loss. Speed loss would be thrust, lift loss would be flap retraction if thrust was still available. The pilot allegedly reported thrust loss, that should be highest on the list of causes imo. In the case of double engine failure without any apparent outside influence visible on videos, that would be quite something for investigators to fathom. I don't know if anyone has data to show speed trend at the point the aircraft starts to descend, or a better audio for thrust variations at that point. I'm guessing that the update frequency on FR24 would be too slow to show that sudden change at the highest point achieved. We'll have the answers soon enough, all I can say is there appears to be no clear answers here without the data recorders or clear improved information. Indeed no conclusions whatsoever can be made as to crew actions either. RIP crew and passengers, condolences to the families. 1 user liked this post. |
tumtiddle
2025-06-13T08:16:00 permalink Post: 11900154 |
Are you kidding? The RAT is deployed (at least on Airbus) when you lose normal electrical supply. This will most likely never (or maybe once) happen in any pilots career.. So you most definitely have not heard "many hundreds" of 777/787 in that abnormal state.
As to the no flaps / flaps debate, time will tell. But what is definitely obvious is that they never raise the gear. Now that is tangible, and to me it seems that initially the aircraft is climbing at a somewhat steady climb until it doesn't. Having flown both Boeings and Airbus+ numerous other types over the years, on every type I have ever flown the initial action once positive climb is determined, is to raise the gear. This goes for every takeoff, normal or with failure of any sort (with the exception of a dual engine failure at rotation, which is not the case here, as they initially climbed to xxx hundred feet). So, initially the gear should have been retracted in order to minimise drag, and the question is, why was it not? Of course, once the gear is up, and in an instance where you get a dual engine failure at low level (highly rare) over land, then it is good arimanship to extend the gear in order for it to take some of the impact when a forced landing is inevitable. But why they did not raise the gear after rotation is a mystery to me. 23 users liked this post. |
Ngineer
2025-06-13T09:11:00 permalink Post: 11900223 |
I didn\x92t think this could be a dual engine failure related accident until reports of RAT deployment started to gather steam.
A few years back a B787 previously had a dual engine shutdown after rollout when the TR was deployed too quickly and not allowing the air/GND logic time to transition to ground mode before the TR deployed. If the TCMA had inadvertently latched the TR deployment from the previous rollout then it theoretically could be possible to shutdown on transition back to air mode. Anything is possible with these high tech machines. 2 users liked this post. |
flemingcool
2025-06-13T09:26:00 permalink Post: 11900239 |
I didn\x92t think this could be a dual engine failure related accident until reports of RAT deployment started to gather steam.
A few years back a B787 previously had a dual engine shutdown after rollout when the TR was deployed too quickly and not allowing the air/GND logic time to transition to ground mode before the TR deployed. If the TCMA had inadvertently latched the TR deployment from the previous rollout then it theoretically could be possible to shutdown on transition back to air mode. Anything is possible with these high tech machines. RIP to all the victims. |
Screamliner
2025-06-13T09:36:00 permalink Post: 11900252 |
Hi everyone, 787 driver here, well lets look at the facts we see
very late rotation, but pitch and departure path look like normal up until stalling point. mayday was called but without clarification or purpose, for me this indicates stress in the flight deck, especially low level no smoke or fire from engines, I would rule out severe damage or birdstrikes at this point Flaps 5 departure would be difficult to see as a pixel on a bad video, but they would not have made the rotation at that speed so I assume they used flaps during departure, also you would neglect to ECL's and a config warning no RAT to be seen either, again ruling out dual engine failure, also the climb would not have been so parabolic maybe single engine fuel starvation/Mechanical issue/dirty fuel, but seems unlikely, the flight path is too gentle Gear stays down, and even though the pitch remains the same, they start losing lift and basically stall the aircraft into the ground don't forget, Air India uses 64/67K engines on they're 787's, with temp of 41 degrees (ambient, so even more above tarmac) and a QNH of 1001, those engines will be pushed to "hard work mode" already IMHO, two things I could assume happend - either single engine failure, no pitch adjustment and speed fell below Vstall, OR, most likely - mixup of Flaps moved to up position in stead of Gear moved to up position, that would clarify the gear, would clarify the loss of lift and that the engines have no smoke, and no RAT, 10 users liked this post. |
bobbytables
2025-06-13T10:01:00 permalink Post: 11900273 |
Hi everyone, 787 driver here, well lets look at the facts we see
very late rotation, but pitch and departure path look like normal up until stalling point. mayday was called but without clarification or purpose, for me this indicates stress in the flight deck, especially low level no smoke or fire from engines, I would rule out severe damage or birdstrikes at this point Flaps 5 departure would be difficult to see as a pixel on a bad video, but they would not have made the rotation at that speed so I assume they used flaps during departure, also you would neglect to ECL's and a config warning no RAT to be seen either, again ruling out dual engine failure, also the climb would not have been so parabolic maybe single engine fuel starvation/Mechanical issue/dirty fuel, but seems unlikely, the flight path is too gentle Gear stays down, and even though the pitch remains the same, they start losing lift and basically stall the aircraft into the ground don't forget, Air India uses 64/67K engines on they're 787's, with temp of 41 degrees (ambient, so even more above tarmac) and a QNH of 1001, those engines will be pushed to "hard work mode" already IMHO, two things I could assume happend - either single engine failure, no pitch adjustment and speed fell below Vstall, OR, most likely - mixup of Flaps moved to up position in stead of Gear moved to up position, that would clarify the gear, would clarify the loss of lift and that the engines have no smoke, and no RAT, very late rotation - stated several times on this thread but zero evidence for it and some analysis suggests the rotation was at roughly the same location as previous departures of the same flight no RAT - others, including one with a lot of experience with the sound of a deployed RAT, insist that it was deployed. The video evidence is unclear. Not saying you\x92re necessarily wrong about anything but I take issue with those that state as fact things that are not (yet) supported by any evidence at all 18 users liked this post. |
tumtiddle
2025-06-13T10:10:00 permalink Post: 11900286 |
One has to assume that, given the seeming lack of lateral deviation from the flight path, and with no obvious yawing or rudder input visible on the videos, there's only two realistic conclusions here? Simultaneous dual engine failure of unknown cause if the RAT was indeed deployed; or flaps reduced too early leading to a stall if the RAT wasn't deployed.
Evidence in this thread would lean me toward the RAT deployed and therefore dual engine out scenario. As for the cause of that, well, only a couple of likely scenarios exist that could cause simultaneous shutdown of both engines, including mistaken or intentional use of the fuel cutoff levers. 3 users liked this post. |
X-37
2025-06-13T10:23:00 permalink Post: 11900306 |
20+ years retired 777 Captain so not at all up to speed..
If you selected gear up but at that moment or just before there was a dual engine failure, would the gear move? Just curious as to how things work. |
pampel
2025-06-13T10:46:00 permalink Post: 11900336 |
The idea that the flaps weren't set for take off also seems incredibly dubious given that in several frames of the original footage you can see the engines through the wings, on both sides, something not explainable by grainy footage or compression artifacts, and only possible if the flaps are down. Edit to add: the reports on social media from the previous passengers complaining about non-functional electronics have been confirmed Last edited by pampel; 13th Jun 2025 at 11:31 . 3 users liked this post. |
C2H5OH
2025-06-13T11:32:00 permalink Post: 11900388 |
One has to assume that, given the seeming lack of lateral deviation from the flight path, and with no obvious yawing or rudder input visible on the videos, there's only two realistic conclusions here? Simultaneous dual engine failure of unknown cause if the RAT was indeed deployed; or flaps reduced too early leading to a stall if the RAT wasn't deployed.
Evidence in this thread would lean me toward the RAT deployed and therefore dual engine out scenario. As for the cause of that, well, only a couple of likely scenarios exist that could cause simultaneous shutdown of both engines, including mistaken or intentional use of the fuel cutoff levers. |
Compton3fox
2025-06-13T11:45:00 permalink Post: 11900402 |
I didn\x92t think this could be a dual engine failure related accident until reports of RAT deployment started to gather steam.
A few years back a B787 previously had a dual engine shutdown after rollout when the TR was deployed too quickly and not allowing the air/GND logic time to transition to ground mode before the TR deployed. If the TCMA had inadvertently latched the TR deployment from the previous rollout then it theoretically could be possible to shutdown on transition back to air mode. Anything is possible with these high tech machines. been examples in the past where it does something it wasn't supposed to do, causing an incident. |
CW247
2025-06-13T11:58:00 permalink Post: 11900416 |
Edit: How do we know it happened at 100ft?
I'm trying to explain the appearance of the RAT and the onboard green/white flashing lights. The alternatives right now are dual engine failure with no birds around. |
Chesty Morgan
2025-06-13T12:16:00 permalink Post: 11900432 |
I said below 100 feet, it didn't get higher than that. Are there any memory items, or indeed emergency checklists, to complete between V1 and 400 feet?
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nachtmusak
2025-06-13T12:20:00 permalink Post: 11900441 |
Related question: I asked earlier at what speed the 787's RAT becomes effective in providing hydraulic power. Is it possible that by the time the RAT deployed, the aircraft had lost airspeed to the point that it would have struggled to produce an adequate amount of pressure? Taking the Gimli Glider incident as an example, my understanding (could be wrong, this was from a magazine article) is that as they bled off speed to land, they ended up short enough of hydraulic power that they started to experience control difficulties, with the plane responding fairly sluggishly. If that's the case and this poor crew was going through something similar, it might explain why they seem to do very little about their situation.
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lighttwin2
2025-06-13T12:27:00 permalink Post: 11900451 |
Presumably a dual engine shutdown under TMCA (i.e. similar to the ANA incident) would cause the RAT to deploy.
Obviously difficult to envisage what could cause an TMCA activation on both engines simultaneously given the safeguards in place (weight on wheels etc). However maybe the time delay from an erroneous TMCA activation on the runway/at rotation would lead to a loss of power 10 seconds later. |
violator
2025-06-13T12:56:00 permalink Post: 11900487 |
Question is why both engines lost power . Foreign object ingestion , contaminated fuel or both cutoff levels operated ? We do not know .
Any autothrust discussion is misleading since every pilot in that situation will firewall the levers whatever thrust reduction was selected for TO . the same is true for the RAT discussion- if enough hydraulic pressure was generated or not . The plane pitched up last second so there obviously was control until the end . Of course , without energy pulling alone will not bring you anywhere . Why did both engines fail the same second as they would be cut off ??? Let\x92s be careful about absolutes. Emirates 521 and Turkish 1951 are both examples of crews not firewalling the thrust levers despite low energy. The late pitch up could be due to the onset of a stall not an order from the crew. TCMA is function which can reduce thrust on both engines simultaneously. It had done so in error in the past resulting in an AD. It uses air/ground logic so that it only operates on the ground, however note that at the point of thrust loss the gear is still down without any movement of the gear or doors. I would expect gear retraction to start before that height. Could we imagine an air/ground logic fault inhibiting gear retraction and allowing TCMA, which triggered (for whatever reason!) causing dual thrust loss? I would expect this to be in the realms of a combination of failures shown to be extremely impossible, but\x85 2 users liked this post. |
dragon6172
2025-06-13T13:26:00 permalink Post: 11900517 |
The only thing that is clear from the footage is that the gear remains down. Which has led to the theory that the loss of lift is a result of the flaps being raised by mistake.
However a deployed RAT would be compelling evidence of dual engine failure or shutdown. Another explanation for the gear remaining down could be startle/distraction caused by engines rolling back at around rotate or liftoff. 1 user liked this post. |
Luc Lion
2025-06-13T14:05:00 permalink Post: 11900549 |
I didn\x92t think this could be a dual engine failure related accident until reports of RAT deployment started to gather steam.
A few years back a B787 previously had a dual engine shutdown after rollout when the TR was deployed too quickly and not allowing the air/GND logic time to transition to ground mode before the TR deployed. If the TCMA had inadvertently latched the TR deployment from the previous rollout then it theoretically could be possible to shutdown on transition back to air mode. Anything is possible with these high tech machines. ANA 787 Engines shutdown during landing and in AvHerald: https://avherald.com/h?article=4c2fe53a&opt=0 Just to clarify one point: the ANA B787 was powered with RR Trent 1000 engines while the Air India had GEnx-1B67 engines. So, the Air India thrust failure may still have its source in the TCMA system, however, if it's the case, the logical path must be somewhat different than for the thrust reversers of the ANA airplane. |
HUTCHP
2025-06-13T14:18:00 permalink Post: 11900557 |
One has to assume that, given the seeming lack of lateral deviation from the flight path, and with no obvious yawing or rudder input visible on the videos, there's only two realistic conclusions here? Simultaneous dual engine failure of unknown cause if the RAT was indeed deployed; or flaps reduced too early leading to a stall if the RAT wasn't deployed.
Evidence in this thread would lean me toward the RAT deployed and therefore dual engine out scenario. As for the cause of that, well, only a couple of likely scenarios exist that could cause simultaneous shutdown of both engines, including mistaken or intentional use of the fuel cutoff levers. Hutch 11 users liked this post. |
nrunning24
2025-06-13T14:21:00 permalink Post: 11900563 |
Former Boeing Engineer, actually worked on this specific airplane prior to delivery. To me this all comes down to if the RAT was actually out. If not, lots of different factors people have already debated and likely some sort of pilot error that I'll let the pilots on this forum debate.
If the RAT did come out, then we are looking at simultaneous dual engine failure basically at V2 which is so improbable (without bird strikes or purposeful actions) that it is basically impossible. This is a 330 Min ETOPS aircraft. I saw no rudder deflection or yaw indicating 1 engine failed first and then they shut down the second one on accident. Only two realistic options for me in that case are: 1. cutoff of the engines by the pilots. Either on purpose or accidental. 2. maintenance actions by the Air India ground team that caused issues with the engine system or power generation system. 2 is the only one I haven't seen mentioned here and I say this as a no longer Boeing employee. We STRUGGLED with AI during the EIS. They were notorious for just parking airplanes and then using them as spare parts and then screaming for help when they had to go back and get the planes ready to fly again. Still think 1 is much more likely but will just throw out that 2 since there were complaints from previous flights about IFE and AC which to me speaks to issues with the power generation possibly being neglected. 18 users liked this post. |
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