2025-06-13T06:45:00
permalink Post: 11900070
Re fuel contamination. Shouldn\x92t the engines be feeding from separate tanks at that point? What are the odds of simultaneous Engine Failure? (Basing that on there is little yaw or wing drop to the live)
It\x92s years since I looked at it. I thought it was in the FARs explicitly but I can only find CFR 25.1309 states the safety analysis for equipment systems and installations that would be likely encompass this.
It\x92s years since I looked at it. I thought it was in the FARs explicitly but I can only find CFR 25.1309 states the safety analysis for equipment systems and installations that would be likely encompass this.
If the fuel from the bowser/ground tank was contaminated it would affect both engines.
However, this would also have affected other aircraft at the airport. It could of course been refuelled with the wrong fuel, but that\x92s pretty much unheard of, and big engines like this can pretty much run on anything that will burn.
1 user liked this post.
2025-06-13T07:03:00
permalink Post: 11900085
To me the radio call signals possibly helplessness and confusion.I do not think a pilot who understands what is going on would make the call. He would be too busy trouble shooting. It could be a sign that is was NOT an engine failure or a bird strike ( in both cases they would have mentioned it). Nor a deliberate crash. They had no idea why they could not climb and that tells me they most probably retracted the flaps. Time will tell.
Last edited by Sisiphos; 13th Jun 2025 at 07:22 .
4 users liked this post.
2025-06-13T07:30:00
permalink Post: 11900107
2025-06-13T07:31:00
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.
2 users liked this post.
2025-06-13T07:36:00
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.
2 users liked this post.
2025-06-13T08:06:00
permalink Post: 11900137
6 users liked this post.
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.
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.
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.
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.
2025-06-13T09:03:00
permalink Post: 11900213
https://assets.publishing.service.go...211_G-POWN.pdf
One example of fuel contamination causing a significant loss of thrust on both engines at low altitude.
But it seems extremely unlikely for contaminated fuel to impact both engines at exactly the same time, with no asymmetry and no surges or smoke.
What can cause a sudden catastrophic loss of thrust on both engines at exactly the same time?
Birds (but no apparent surges)
Inadvertent movement of the fuel cut off switches (which would be an incredible error but I suppose it could conceivably be muscle memory having done so recently after the last leg…weirder things have happened. Remember the 767 events of the late 80s)
Intentional shutdown of the engines (pilot suicide has happened before)
Some catastrophic electrical/FADEC/engine interface failure (which I highly doubt is feasible in a modern 1309 aircraft)
I can’t think of any others…
One example of fuel contamination causing a significant loss of thrust on both engines at low altitude.
But it seems extremely unlikely for contaminated fuel to impact both engines at exactly the same time, with no asymmetry and no surges or smoke.
What can cause a sudden catastrophic loss of thrust on both engines at exactly the same time?
Birds (but no apparent surges)
Inadvertent movement of the fuel cut off switches (which would be an incredible error but I suppose it could conceivably be muscle memory having done so recently after the last leg…weirder things have happened. Remember the 767 events of the late 80s)
Intentional shutdown of the engines (pilot suicide has happened before)
Some catastrophic electrical/FADEC/engine interface failure (which I highly doubt is feasible in a modern 1309 aircraft)
I can’t think of any others…
I cant think of any reason for electrical failure and "no thrust" (as per statements) without any visual cues other than (a) suicide, or (b) starvation. Is there any electrical failure that can cause fuel valves to close? I dont fly Boeing, so can any Dreamliner driver explain what conditions could trigger an overspeed and auto engine shutdown (quote from Google below)? Would short runway, and hot/low QNH do it? Also, what happened to the order demanding a full power down/recycle every 51 days?
The EEC has build in protections to protect the engine. One of these protections is the Engine Overspeed Protection, when the core engine exceeds 120% the EEC shuts off the fuel to the applicable engine.
Last edited by Arrowhead; 13th Jun 2025 at 09:46 .
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.
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.
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.
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.
2025-06-13T09:30:00
permalink Post: 11900245
I'm sorry but pilots are taught to recognise lack of acceleration during takeoff. They're also taught about cross checking FMC entries during setup. How are they taught? By me and many others.
Even if the pilots had the wrong FMC performance, it would be noticed in the before takeoff cxl.
Even if the pilots had the wrong FMC performance, it would be noticed in the before takeoff cxl.
I often contemplate when I rattle down the runway with 375 metric tons if I really hit V1 at the right place of the concrete strip. Although I learned how it feels when you stop with this weight at this very moment (engine failure with MTOM).
2 users liked this post.
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,
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.
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, 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.
2025-06-13T10:06:00
permalink Post: 11900279
This seems to be the best summary so far. Based on the detail of the mayday its probably time to rule out the flaps, load shift, and other suggestions.
I cant think of any reason for "no thrust" (as per ATC) without any visual cues other than (a) suicide, or (b) starvation. Is there any electrical failure that can cause fuel valves to close? I dont fly Boeing, so can any Dreamliner driver explain what conditions could trigger an overspeed and auto engine shutdown (quote from Google below)? Would short runway, and hot/low QNH do it?
The EEC has build in protections to protect the engine. One of these protections is the Engine Overspeed Protection, when the core engine exceeds 120% the EEC shuts off the fuel to the applicable engine.
I cant think of any reason for "no thrust" (as per ATC) without any visual cues other than (a) suicide, or (b) starvation. Is there any electrical failure that can cause fuel valves to close? I dont fly Boeing, so can any Dreamliner driver explain what conditions could trigger an overspeed and auto engine shutdown (quote from Google below)? Would short runway, and hot/low QNH do it?
The EEC has build in protections to protect the engine. One of these protections is the Engine Overspeed Protection, when the core engine exceeds 120% the EEC shuts off the fuel to the applicable engine.
Many GE engines - including GEnx-1B/67s - require microprocessors to be routinely replaced due to soldered joints failing after multiple cycles. There is a 2021 AD that notes "This AD was prompted by an in-service occurrence of loss of engine thrust control resulting in uncommanded high thrust" (I cannot post a link but google: 2021-25491 (86 FR 66447))
I am NOT suggesting that this specific failure mode happened here - for one thing, this would happen to one engine, not both. But on any flight it is possible that a unique set of sensor inputs to occur that are the first time any system has encountered them (example: NATS incident in 2023), and then you need failover & redundancy to keep things working.
The GE Aviation CCS system, which includes thrust management, has up to now flown for 1m flight hours without incident. It would be interesting to hear the perspectives of any engineers familiar with the system.
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.
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.
2025-06-13T10:12:00
permalink Post: 11900291
I\x92d like to ask a legitimate question here regarding the runway footage.
there seems to be little to no change in aircraft attitude from point of lift off until just before impact.
I have no experience on commercial jets, so I am waiting to be corrected, but first thing in engine failure after take off is lower the nose? If RAT deployed they should have at least been able to do so?
The fact the attitude remains unchanged, would this not suggest they at least thought they had a chance of flying their way out of this situation?
im sure 787 is not prone to pitot/static blockage?
time will tell, until then we can only speculate I guess.
there seems to be little to no change in aircraft attitude from point of lift off until just before impact.
I have no experience on commercial jets, so I am waiting to be corrected, but first thing in engine failure after take off is lower the nose? If RAT deployed they should have at least been able to do so?
The fact the attitude remains unchanged, would this not suggest they at least thought they had a chance of flying their way out of this situation?
im sure 787 is not prone to pitot/static blockage?
time will tell, until then we can only speculate I guess.
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.
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.
2025-06-13T10:45:00
permalink Post: 11900333
I think this is the wrong attitude and technique, but it's an opinion.
To me the radio call signals possibly helplessness and confusion.I do not think a pilot who understands what is going on would make the call. He would be too busy trouble shooting. It could be a sign that is was NOT an engine failure or a bird strike ( in both cases they would have mentioned it). Nor a deliberate crash. They had no idea why they could not climb and that tells me they most probably retracted the flaps. Time will tell.
To me the radio call signals possibly helplessness and confusion.I do not think a pilot who understands what is going on would make the call. He would be too busy trouble shooting. It could be a sign that is was NOT an engine failure or a bird strike ( in both cases they would have mentioned it). Nor a deliberate crash. They had no idea why they could not climb and that tells me they most probably retracted the flaps. Time will tell.
Of course the didn't know why they'd lost power, they just knew they'd lost it. Yeh they would have felt pretty helpless 200 feet above the ground surrounded by tall buildings. My heart goes out to them being by that point no more than passengers to their own death. At least the actual passengers didn't have to watch the building coming at them knowing there was no escape. It's unthinkable.
So I don't know how on earth you think this suggests the flap theory. You're reading an awful lot into the words of a man who was likely processing the fact he's about to die in a horrific way.
Can we just forget about flaps? We have pictures of the wing at the crash site with flaps extended. The plane is on video with no engine noise and the RAT audible and visible. The pilot sent a mayday saying they'd lost thrust. The only survivor says the lights were flickering and the cabin went dark. Why are some people so desperate to pin this on a pilot mistake there is zero evidence for?
33 users liked this post.
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.