June 13, 2025, 07:24:00 GMT
permalink Post: 11900099
My theory on this is a wrong weight/temperature entry, too much derating, attempted take-off in too low an energy state and subsequent departure stall.
From the airport cam video, the aircraft seems to stick off just at the end of the runway.
Both engines are working at full blast until at least obstacle clearance height, they kick up unusual amounts of dust for a take-off.
Theoretical sequence of events:
1. Pilots entered the wrong take off perf data
2. During the take-off roll they realize that the aircraft isn't picking up enough speed but too late to reject and firewall the throttles
3. They use up the whole runway and get the aircraft off the ground in ground effect
4. Ground effect ends and they fail to maintain a positive rate of climb, hence gears stay down
5. Aircraft stalls and sinks into the ground
Textbook departure stall and failure to pitch down to recover from it.
From the airport cam video, the aircraft seems to stick off just at the end of the runway.
Both engines are working at full blast until at least obstacle clearance height, they kick up unusual amounts of dust for a take-off.
Theoretical sequence of events:
1. Pilots entered the wrong take off perf data
2. During the take-off roll they realize that the aircraft isn't picking up enough speed but too late to reject and firewall the throttles
3. They use up the whole runway and get the aircraft off the ground in ground effect
4. Ground effect ends and they fail to maintain a positive rate of climb, hence gears stay down
5. Aircraft stalls and sinks into the ground
Textbook departure stall and failure to pitch down to recover from it.
June 13, 2025, 07:30:00 GMT
permalink Post: 11900107
June 13, 2025, 07:31:00 GMT
permalink Post: 11900108
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.
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.
June 13, 2025, 07:36:00 GMT
permalink Post: 11900111
People on here seem convinced the RAT was deployed because they\x92ve seen it/heard it so many times before. They may be right. But if they are, then it means the RAT has deployed countless times before without both engines having failed, so it doesn\x92t definitively tell us anything.
System-wide electrical issues
Double engine failure
Selection of fuel switch and/or fire switch on both engines
Any speculation about gear, flap, runway, etc. is redundant if the RAT did auto-deploy as it points to a very serious technical issue with the airframe rather than what was done with thrust levers or what the pilots had for breakfast.
I haven\x92t seen what the 787 cockpit looks like on battery power only but on the 777 it gets pretty dark with only the essential P1 instruments and VHF1 available until the RAT comes online, which is a measurable amount of time after deployment is triggered.
June 13, 2025, 07:36:00 GMT
permalink Post: 11900113
The latest hi res video does have audio and very clear. You can hear a RAT sound as it passes by or certainly a deep propeller sound, And a blob where the RAT would be. Only the FDR will help here, That would point to total power loss. But the sudden loss of lift apparent in the video doesn't look like power loss.
June 13, 2025, 07:50:00 GMT
permalink Post: 11900127
Every Boeing (and Airbus) twin plus the 747-8 has a RAT -.
The Boeing 737?
The Airbus 220?
Is there a reason the setting should not default after a landing to ‘Input required’?
June 13, 2025, 08:06:00 GMT
permalink Post: 11900136
June 13, 2025, 08:06:00 GMT
permalink Post: 11900137
June 13, 2025, 08:07:00 GMT
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.
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.
June 13, 2025, 08:09:00 GMT
permalink Post: 11900142
What the 767s I flew did have, was a hydraulic generator (or 2 in some cases), but that sure ain\x92t a RAT.
June 13, 2025, 08:16:00 GMT
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.
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.
June 13, 2025, 08:47:00 GMT
permalink Post: 11900195
RAT? Here\x92s an unprocessed frame from the video. I really don\x92t see that the RAT has deployed.
June 13, 2025, 08:54:00 GMT
permalink Post: 11900208
Electrical AC loss results in the activation of an emergency geberator driven by the green system.
A4
June 13, 2025, 09:04:00 GMT
permalink Post: 11900214
Probably the best, early stage theory of the the cause that I have seen as yet. By a current 777 captain:
https://www.youtube.com/watch?v=z7EZkungFEE
https://www.youtube.com/watch?v=z7EZkungFEE
June 13, 2025, 09:11:00 GMT
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.
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.
June 13, 2025, 09:26:00 GMT
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.
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.
June 13, 2025, 09:36:00 GMT
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,
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,
June 13, 2025, 09:49:00 GMT
permalink Post: 11900263
June 13, 2025, 10:01:00 GMT
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, 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
June 13, 2025, 10:03:00 GMT
permalink Post: 11900277
Flap - gear mix-up indeed seems most consistent - if there was no RAT. But looks to me their anomaly started when the automation switches from ground to fly mode. So is there some automation that could potentially cut or idle both engines during that transition?
It's just too simple to be true. I expect/hope for some Swiss Cheese type failure.
It's just too simple to be true. I expect/hope for some Swiss Cheese type failure.