2025-06-13T11:18:00
permalink Post: 11900373
Plane crash near Ahmedabad
Here is a very unlikely scenario. It may be possible that there was nothing wrong with the aircraft.
We have been told the experience levels of the pilots but not how long they have been flying the 787.
The 787 is very automatic and, in my experience, the easiest aircraft to fly. It does a lot of things for you and reminds you of things that you may have forgotten to do. For that reason, in my opinion it is also the safest aircraft around. However, you have to understand what the automatics are doing in order to manage it correctly.
By putting the departure route into the FMC you set up the lateral navigation and also the vertical navigation including speeds and altitudes. After take-off the FMC will command you initially to fly at up to V2 + 20 until flap retraction ( normally no lower than 1000 feet agl), and then increase the speed with flap retraction until initial climb speed and then final climb speed above FL 100.
If your first altitude restriction on departure is 4000 feet (which will be in the FMC) and VNAV is engaged you will level at 4000 feet. But, if prior to departure, you put 3000 feet in the altitude window (maybe as instructed by ATC) the aircraft will level at 3000 feet.
If I remember correctly LNAV engages at 50 feet and VNAV engages at 400 feet agl. And, I may be mistaken, but I think that the auto-pilot could be engaged at 100 feet agl.
Now, I am probably wrong about this, but if you forget to set the altitude window to the first altitude in departure and leave it at 0 (which with some airlines the previous crew will do on shutdown) the following might possibly occur. At 50 feet LNAV engages, at 100 feet the autopilot engages, at 400 feet VNAV engages but as the altitude window is set to 0 the aircraft (on autopilot) now descends to capture 0 feet. The speed at this point in VNAV is low (max V2 + 20 kts) so, to maintain that, both thrust levers close. This, of course, would be totally unexpected and could have a startle effect. If you do not realise what has caused this you might think that there is a problem with the engines and you have very little time to deal with it. I would suggest that putting out a Mayday call at this stage is not a good use of time.
As I stated at the beginning this is probably very unlikely and may not be possible, but could be tried in a simulator.
We have been told the experience levels of the pilots but not how long they have been flying the 787.
The 787 is very automatic and, in my experience, the easiest aircraft to fly. It does a lot of things for you and reminds you of things that you may have forgotten to do. For that reason, in my opinion it is also the safest aircraft around. However, you have to understand what the automatics are doing in order to manage it correctly.
By putting the departure route into the FMC you set up the lateral navigation and also the vertical navigation including speeds and altitudes. After take-off the FMC will command you initially to fly at up to V2 + 20 until flap retraction ( normally no lower than 1000 feet agl), and then increase the speed with flap retraction until initial climb speed and then final climb speed above FL 100.
If your first altitude restriction on departure is 4000 feet (which will be in the FMC) and VNAV is engaged you will level at 4000 feet. But, if prior to departure, you put 3000 feet in the altitude window (maybe as instructed by ATC) the aircraft will level at 3000 feet.
If I remember correctly LNAV engages at 50 feet and VNAV engages at 400 feet agl. And, I may be mistaken, but I think that the auto-pilot could be engaged at 100 feet agl.
Now, I am probably wrong about this, but if you forget to set the altitude window to the first altitude in departure and leave it at 0 (which with some airlines the previous crew will do on shutdown) the following might possibly occur. At 50 feet LNAV engages, at 100 feet the autopilot engages, at 400 feet VNAV engages but as the altitude window is set to 0 the aircraft (on autopilot) now descends to capture 0 feet. The speed at this point in VNAV is low (max V2 + 20 kts) so, to maintain that, both thrust levers close. This, of course, would be totally unexpected and could have a startle effect. If you do not realise what has caused this you might think that there is a problem with the engines and you have very little time to deal with it. I would suggest that putting out a Mayday call at this stage is not a good use of time.
As I stated at the beginning this is probably very unlikely and may not be possible, but could be tried in a simulator.
9 users liked this post.
2025-06-13T11:34:00
permalink Post: 11900389
It's fine that the \x93Enhanced Airborne Flight Recorders\x94 have 10 minutes battery backup. If the bits of equipment/sensors sending data to be recorded don't have power, you will be recording 10 minutes of silence/blank data.
The concept of powering 'critical (sensor) equipment' has been floated - the problem being that it must be possible to power down malfunctioning equipment in case of fire - real or suspected. Having independent power supplies and battery back-ups all around the airframe, each with an ability to lose their magic smoke, is a poor idea.
Commercial passenger jet aircraft already have robust power supplies with multiple generators and emergency battery support. However, if one malfunctions, rather than fails completely, it can be difficult to decide which one to disable, as it can cause problems in all systems.
The concept of powering 'critical (sensor) equipment' has been floated - the problem being that it must be possible to power down malfunctioning equipment in case of fire - real or suspected. Having independent power supplies and battery back-ups all around the airframe, each with an ability to lose their magic smoke, is a poor idea.
Commercial passenger jet aircraft already have robust power supplies with multiple generators and emergency battery support. However, if one malfunctions, rather than fails completely, it can be difficult to decide which one to disable, as it can cause problems in all systems.
Once the RAT deployed at least some data should have come back.
Now, I am probably wrong about this, but if you forget to set the altitude window to the first altitude in departure and leave it at 0 (which with some airlines the previous crew will do on shutdown) the following might possibly occur. At 50 feet LNAV engages, at 100 feet the autopilot engages, at 400 feet VNAV engages but as the altitude window is set to 0 the aircraft (on autopilot) now descends to capture 0 feet. The speed at this point in VNAV is low (max V2 + 20 kts) so, to maintain that, both thrust levers close. This, of course, would be totally unexpected and could have a startle effect. If you do not realise what has caused this you might think that there is a problem with the engines and you have very little time to deal with it. I would suggest that putting out a Mayday call at this stage is not a good use of time.
As I stated at the beginning this is probably very unlikely and may not be possible, but could be tried in a simulator.
As I stated at the beginning this is probably very unlikely and may not be possible, but could be tried in a simulator.
It does not explain the RAT and generally you would expect crews to shove the thrust levers fully forward.
1 user liked this post.
2025-06-13T11:53:00
permalink Post: 11900411
Assumptions
30 secs to 100 kts from TO power set.and 200 kts after 60 seconds
Impact occurred 30 secs after Vr 1 nm out, so about 120 kts and no more than 300ft
The gear was not or could not be retracted.
Without doubt the crew knew impact was inevitable at least 10 seconds prior to impact noted by body angle change in video evidence
whether a Mayday Call was in fact made or not.
I think that the only thing that would matter for any of us in that 20 seconds would be THRUST and everything it's got.
Which occurred first, the loss of thrust on both engines causing all generators to go offline or a total electrical failure that caused flight Idle thrust.
30 secs to 100 kts from TO power set.and 200 kts after 60 seconds
Impact occurred 30 secs after Vr 1 nm out, so about 120 kts and no more than 300ft
The gear was not or could not be retracted.
Without doubt the crew knew impact was inevitable at least 10 seconds prior to impact noted by body angle change in video evidence
whether a Mayday Call was in fact made or not.
I think that the only thing that would matter for any of us in that 20 seconds would be THRUST and everything it's got.
Which occurred first, the loss of thrust on both engines causing all generators to go offline or a total electrical failure that caused flight Idle thrust.
2025-06-13T12:22:00
permalink Post: 11900444
Here is a very unlikely scenario. It may be possible that there was nothing wrong with the aircraft.
We have been told the experience levels of the pilots but not how long they have been flying the 787.
The 787 is very automatic and, in my experience, the easiest aircraft to fly. It does a lot of things for you and reminds you of things that you may have forgotten to do. For that reason, in my opinion it is also the safest aircraft around. However, you have to understand what the automatics are doing in order to manage it correctly.
By putting the departure route into the FMC you set up the lateral navigation and also the vertical navigation including speeds and altitudes. After take-off the FMC will command you initially to fly at up to V2 + 20 until flap retraction ( normally no lower than 1000 feet agl), and then increase the speed with flap retraction until initial climb speed and then final climb speed above FL 100.
If your first altitude restriction on departure is 4000 feet (which will be in the FMC) and VNAV is engaged you will level at 4000 feet. But, if prior to departure, you put 3000 feet in the altitude window (maybe as instructed by ATC) the aircraft will level at 3000 feet.
If I remember correctly LNAV engages at 50 feet and VNAV engages at 400 feet agl. And, I may be mistaken, but I think that the auto-pilot could be engaged at 100 feet agl.
Now, I am probably wrong about this, but if you forget to set the altitude window to the first altitude in departure and leave it at 0 (which with some airlines the previous crew will do on shutdown) the following might possibly occur. At 50 feet LNAV engages, at 100 feet the autopilot engages, at 400 feet VNAV engages but as the altitude window is set to 0 the aircraft (on autopilot) now descends to capture 0 feet. The speed at this point in VNAV is low (max V2 + 20 kts) so, to maintain that, both thrust levers close. This, of course, would be totally unexpected and could have a startle effect. If you do not realise what has caused this you might think that there is a problem with the engines and you have very little time to deal with it. I would suggest that putting out a Mayday call at this stage is not a good use of time.
As I stated at the beginning this is probably very unlikely and may not be possible, but could be tried in a simulator.
We have been told the experience levels of the pilots but not how long they have been flying the 787.
The 787 is very automatic and, in my experience, the easiest aircraft to fly. It does a lot of things for you and reminds you of things that you may have forgotten to do. For that reason, in my opinion it is also the safest aircraft around. However, you have to understand what the automatics are doing in order to manage it correctly.
By putting the departure route into the FMC you set up the lateral navigation and also the vertical navigation including speeds and altitudes. After take-off the FMC will command you initially to fly at up to V2 + 20 until flap retraction ( normally no lower than 1000 feet agl), and then increase the speed with flap retraction until initial climb speed and then final climb speed above FL 100.
If your first altitude restriction on departure is 4000 feet (which will be in the FMC) and VNAV is engaged you will level at 4000 feet. But, if prior to departure, you put 3000 feet in the altitude window (maybe as instructed by ATC) the aircraft will level at 3000 feet.
If I remember correctly LNAV engages at 50 feet and VNAV engages at 400 feet agl. And, I may be mistaken, but I think that the auto-pilot could be engaged at 100 feet agl.
Now, I am probably wrong about this, but if you forget to set the altitude window to the first altitude in departure and leave it at 0 (which with some airlines the previous crew will do on shutdown) the following might possibly occur. At 50 feet LNAV engages, at 100 feet the autopilot engages, at 400 feet VNAV engages but as the altitude window is set to 0 the aircraft (on autopilot) now descends to capture 0 feet. The speed at this point in VNAV is low (max V2 + 20 kts) so, to maintain that, both thrust levers close. This, of course, would be totally unexpected and could have a startle effect. If you do not realise what has caused this you might think that there is a problem with the engines and you have very little time to deal with it. I would suggest that putting out a Mayday call at this stage is not a good use of time.
As I stated at the beginning this is probably very unlikely and may not be possible, but could be tried in a simulator.
Last edited by JG1; 13th Jun 2025 at 13:15 .
2025-06-13T14:37:00
permalink Post: 11900577
Mechanical (physical) error and mental (flow) error.
If 2 levers are close to each other and you grab the wrong one without looking (condition levers/flaps in turboprop) then that's a mechanical error, unlikely yes here.
But... a mental error choosing the wrong item out of 2 when BOTH are part of normal takeoff procedure would (and has been) a simple error to make if concentration not there for some reason. Or inexperience. Gear up would certainly be the first action once climbing out but what if the pilot flying had actually called flaps 1 or retract flaps? Personally think this is not as likely as loss of power, or premature rotation for available power. Do we know if that MAYDAY was actually made for certain yet? If it was then only a major catastrophic event would divert the pilots from trying to fly the plane to making any radio call. They were (hopefully) on take off thrust the whole time and what goes up does not easily come down without a major change of energy. I was really surprised most by no obvious attempt to lower the nose to gain speed early on. They had clearance altitude for some acceleration. Some terrible CG imbalance maybe? Way too early and minimal facts to even speculate yet.
1 user liked this post.
2025-06-13T16:45:00
permalink Post: 11900682
SLF here, retired physicist, but with much engineering (esp. systems engineering) background and considerable interest/experience in fault-finding in complex (not aircraft) systems.
I think it is helpful here to work through some possible failure scenarios in some detail. You could usefully partition these into two separate groups: “RAT was deployed” and “RAT was not deployed.” I’ll mostly follow the former here.
\xb7 By following this path, I think we can exclude incorrect flaps setting or premature flap retraction as the primary cause of the crash. It’s difficult to see how improper use of the flaps would be correlated with RAT deployment. Everything in this case points to a loss of engine thrust.
\xb7 The first question is, why did the RAT deploy? As I understand it, manual deployment by a pilot is possible, or automatic deployment caused by detection of major electrical or engine failures. I haven’t found an authoritative, detailed discussion of this, or about the time to deployment, which is relevant here as there is so little time involved.
\xb7 According to tdracer , if the primary issue was a major electrical failure, that should not have caused any engine rollback. Thus, absent pull back of the throttles (which surely would have been corrected by the pilots), there should not have been a loss of thrust.
\xb7 Thus we are left with engine rollback as the likely underlying problem. Absent other issues, a single engine rollback should not have been a major problem, so dual rollback, unlikely as it might be, seems a reasonable conclusion.
\xb7 This is consistent with the reported mayday call, although that report needs confirmation.
\xb7 It is difficult to understand a dual engine rollback. Various causes have been suggested but ruled “unlikely” here. However, it is not possible to rule out a unicorn event, like the dual engine rollback experienced by BA 38. Leaving aside the cause, it is useful to look at the consequences.
\xb7 There would have been a major loss of electrical power (apart from battery backup), assuming the APU was not running. I don’t know if is possible the APU might be used at takeoff (e,g., to unload the main engines), or if any evidence from the tail photo at the crash site provides a meaningful indication (e.g., intake door status).
\xb7 Are there other indications of loss of electrical power? The reported statements of the surviving passenger may have some relevance, but I would want to see the results of an interview by crash investigators.
\xb7 What about the loss of Flight Aware ADS-B data shortly after takeoff? There have been a few mentions of this, but not much discussion. Could this indicate loss of electrical power?
I hope this is of some use. I’m happy to defer to professionals or others here for better information/analysis.
I think it is helpful here to work through some possible failure scenarios in some detail. You could usefully partition these into two separate groups: “RAT was deployed” and “RAT was not deployed.” I’ll mostly follow the former here.
\xb7 By following this path, I think we can exclude incorrect flaps setting or premature flap retraction as the primary cause of the crash. It’s difficult to see how improper use of the flaps would be correlated with RAT deployment. Everything in this case points to a loss of engine thrust.
\xb7 The first question is, why did the RAT deploy? As I understand it, manual deployment by a pilot is possible, or automatic deployment caused by detection of major electrical or engine failures. I haven’t found an authoritative, detailed discussion of this, or about the time to deployment, which is relevant here as there is so little time involved.
\xb7 According to tdracer , if the primary issue was a major electrical failure, that should not have caused any engine rollback. Thus, absent pull back of the throttles (which surely would have been corrected by the pilots), there should not have been a loss of thrust.
\xb7 Thus we are left with engine rollback as the likely underlying problem. Absent other issues, a single engine rollback should not have been a major problem, so dual rollback, unlikely as it might be, seems a reasonable conclusion.
\xb7 This is consistent with the reported mayday call, although that report needs confirmation.
\xb7 It is difficult to understand a dual engine rollback. Various causes have been suggested but ruled “unlikely” here. However, it is not possible to rule out a unicorn event, like the dual engine rollback experienced by BA 38. Leaving aside the cause, it is useful to look at the consequences.
\xb7 There would have been a major loss of electrical power (apart from battery backup), assuming the APU was not running. I don’t know if is possible the APU might be used at takeoff (e,g., to unload the main engines), or if any evidence from the tail photo at the crash site provides a meaningful indication (e.g., intake door status).
\xb7 Are there other indications of loss of electrical power? The reported statements of the surviving passenger may have some relevance, but I would want to see the results of an interview by crash investigators.
\xb7 What about the loss of Flight Aware ADS-B data shortly after takeoff? There have been a few mentions of this, but not much discussion. Could this indicate loss of electrical power?
I hope this is of some use. I’m happy to defer to professionals or others here for better information/analysis.
8 users liked this post.
2025-06-13T18:31:00
permalink Post: 11900789
Interested observer here, nothing more; with a question:
If the mayday call has been reported correctly, it states: \x91Mayday! No thrust. Losing power. Cannot lift.\x92
Is the term \x91Cannot lift\x92 standard comms for lack of climb rate/stall? If not, it strikes me that the transcript is incomplete, either due to loss of comms, inaudibility, or even just bad reporting.
\x91Cannot lift gear\x92?
If the mayday call has been reported correctly, it states: \x91Mayday! No thrust. Losing power. Cannot lift.\x92
Is the term \x91Cannot lift\x92 standard comms for lack of climb rate/stall? If not, it strikes me that the transcript is incomplete, either due to loss of comms, inaudibility, or even just bad reporting.
\x91Cannot lift gear\x92?
Last edited by BlueSkyBoy1; 13th Jun 2025 at 19:22 .
2025-06-13T19:31:00
permalink Post: 11900839
In summary,
Flaps were extended, possibly flaps 5 or 15. Looks like it in the video and clearly shown post crash.
Aircraft reached a height of just over 100\x92 AGL (possibly 200\x92 if you compare wingspan to height in videos)
RAT was deployed. Seen on videos and heard conclusively.
Aircraft rotated at \x91usual\x92 spot. Comparing FR24 data from previous flights over the past week.
Aircraft took off at \x91usual\x92 speed. Comparing other flights.
FR24 data stopped being sent shortly after take off. Possibly indicating electrical fault.
Green and white flashing light reported by survivor. Possibly indicating electrical fault.
Gear bogies were at unusual angle indicating Gear selected up and then interrupted.
No smoke or flames to indicate bird strike. (Edit - still debate about this in the video above where the aircraft is behind a building)
No rudder input to indicate single engine failure.
All speculation but hopefully a pretty balanced summary from the thread so far. It would be great if there was more focus now on what might have caused above rather than talking flaps, birds, 625\x92, etc.
Flaps were extended, possibly flaps 5 or 15. Looks like it in the video and clearly shown post crash.
Aircraft reached a height of just over 100\x92 AGL (possibly 200\x92 if you compare wingspan to height in videos)
RAT was deployed. Seen on videos and heard conclusively.
Aircraft rotated at \x91usual\x92 spot. Comparing FR24 data from previous flights over the past week.
Aircraft took off at \x91usual\x92 speed. Comparing other flights.
FR24 data stopped being sent shortly after take off. Possibly indicating electrical fault.
Green and white flashing light reported by survivor. Possibly indicating electrical fault.
Gear bogies were at unusual angle indicating Gear selected up and then interrupted.
No smoke or flames to indicate bird strike. (Edit - still debate about this in the video above where the aircraft is behind a building)
No rudder input to indicate single engine failure.
All speculation but hopefully a pretty balanced summary from the thread so far. It would be great if there was more focus now on what might have caused above rather than talking flaps, birds, 625\x92, etc.
The most productive responses would be along the lines of:-
(1) I too have read all previous posts and agree that your summary reflects the current consensus,
(2) I too have read all previous posts and agree your summary reflects the consensus HOWEVER I challenge that consensus because... [ [i]EITHER (a) reference to previous post that merits greater credence, OR (b) new evidence supplied],
(3) I too have read all previous posts but I do NOT agree your summary reflects the consensus [explanation required].
It is not necessary for everyone who thinks (1) to say it (although some initial feedback would be useful!). However, if any of the more experienced and informed PPRuNers are thinking either (2) or (3) then it would be instructive to hear that.
FWIW, yours strikes me as a reasonable summary of the best consensus I have been able to discern (as of ~30 minutes ago). There are multiple caveats to each line item, but I presume you've deliberately left those out for the sake of readability, so I'll do the same!
The only comments I would add are:-
- It's a stretch to say the RAT is seen or heard "conclusively". Doubts have been expressed about the video quality and there are dissenting views regarding the audio. If a few more people were able to wade in on the audio point in particular, this could be very beneficial in moving the discussion forward because the presence or otherwise of the RAT is significant to several competing theories.
- On the subject of audio, I am surprised there has not been more discussion regarding engine noise. In the primary eye witness video the (alleged) RAT can be heard distinctly, as can the sounds of distant impact. If the engines were working as expected when overflying the camera and then flying directly away from it, do we really not think the engine noise would be more conclusive, i.e. louder (notwithstanding quiet engines and derated takeoffs)?
Whichever way readers are leaning in the flaps versus power loss debate, surely these two points are pivotal, and we have actual evidence available to discuss?
- Gear bogies: I'm not sure a consensus has yet been reached regarding the angle of the bogies. (I am not personally qualified to comment on this - I am purely saying I don't see a clear consensus just yet among those who are)
- Mayday call: I don't recall seeing a confirmed source for the widely reported mayday. Others have brought this up in the thread but nobody appears to be able to confirm one way or the other. If accurate, its contents are informative. Am I right to presume that you have left it out of your summary due to a lack of confirmation?
9 users liked this post.
2025-06-13T20:31:00
permalink Post: 11900874
The only comments I would add are:-
- It's a stretch to say the RAT is seen or heard "conclusively". Doubts have been expressed about the video quality and there are dissenting views regarding the audio. If a few more people were able to wade in on the audio point in particular, this could be very beneficial in moving the discussion forward because the presence or otherwise of the RAT is significant to several competing theories.
- On the subject of audio, I am surprised there has not been more discussion regarding engine noise. In the primary eye witness video the (alleged) RAT can be heard distinctly, as can the sounds of distant impact. If the engines were working
- Gear bogies: I'm not sure a consensus has yet been reached regarding the angle of the bogies. (I am not personally qualified to comment on this - I am purely saying I don't see a clear consensus just yet among those who are)
- Mayday call: I don't recall seeing a confirmed source for the widely reported mayday. Others have brought this up in the thread but nobody appears to be able to confirm one way or the other. If accurate, its contents are informative. Am I right to presume that you have left it out of your summary due to a lack of confirmation?
I simply forgot to mention the Mayday. I think there are enough sources to suggest one was made but I\x92m slightly wary of its content.
The recording and rebroadcast of RT exchanges is illegal in India as it is in the U.K. so we can\x92t be sure until its official release.
Gear bogies - This was also mentioned by Juan Browne/Blancolirio as something to focus on, that\x92s probably what swayed me on this.
I was initially in the gear up/flaps up camp but I\x92ve been impressed by the testimonies of others here, particularly by the poster who\x92s heard hundreds of these overhead and the several videos shared for comparison.
As you say, hopefully we can put most of these topics to bed now (unless there is contradictory new evidence) and focus instead on where Occam\x92s razor points us.
2 users liked this post.
2025-06-13T21:30:00
permalink Post: 11900926
Having read all the posts, watched the videos and with a 30 year background interest in air safety, I have a nagging feeling that the engine fuel cut off switches were pulled just after take-off. I am not saying this with the intention of idle speculation, it is just that to me nothing else seems to make sense. To anyone disagreeing with this, I really hope you are right and I am wrong.
2025-06-13T22:50:00
permalink Post: 11900977
I've been closely examining a video frame captured very early in the footage depicting the aircraft's final moments. In this particular frame, I believe the
left main landing gear (MLG) door is clearly visible in the open position
, while the
right MLG door appears closed
. Additionally, both
main gear bogies are noticeably tilted forward
\x97 a configuration that typically occurs at the initiation of the gear retraction sequence.
This combination strongly suggests that a gear retraction was commanded , but the sequence was interrupted and never completed . What\x92s particularly striking is the asymmetry \x97 the left door open, the right door closed \x97 which should not occur during normal operations and points toward a possible hydraulic failure scenario during retraction.
As many will know, on the Boeing 787-8, each main gear door is hydraulically actuated and powered by its respective side\x92s hydraulic system \x97 the left gear door by the left hydraulic system , and the right by the right . This leads me to propose the following hypothesis:
Further supporting this theory are:
In the meantime, my thoughts are very much with all those affected by this heartbreaking event.
( NOTE: Unfortunately this is my first post here. I wanted to upload the frame for all to see but the forum is restricting me from doing this until I reach 8 posts. I can't link to it via a URL either. I studied a frame from the very start of the video, just as the full aircraft enters view and expanded it by 400% allowing me to see the position of the MLG doors).
This combination strongly suggests that a gear retraction was commanded , but the sequence was interrupted and never completed . What\x92s particularly striking is the asymmetry \x97 the left door open, the right door closed \x97 which should not occur during normal operations and points toward a possible hydraulic failure scenario during retraction.
As many will know, on the Boeing 787-8, each main gear door is hydraulically actuated and powered by its respective side\x92s hydraulic system \x97 the left gear door by the left hydraulic system , and the right by the right . This leads me to propose the following hypothesis:
-
Shortly after rotation, with a positive rate of climb established, the
flight crew commands gear up
.
-
The
gear retraction sequence initiates
; the
main gear bogies tilt forward
, consistent with the start of retraction.
-
The right engine fails first
, resulting in a
loss of right hydraulic system pressure
. Consequently, the
right MLG door does not open
.
-
The
left MLG door, still powered by the left hydraulic system, opens
.
-
Moments later, the left engine also fails
, leading to
loss of the left hydraulic system
. With the door now open but no remaining hydraulic pressure,
the left main gear remains extended and the door remains open
.
-
The
ram air turbine (RAT) deploys
, consistent with total engine and electrical power loss.
-
With the
loss of thrust from both engines
, the aircraft loses lift and enters an unrecoverable descent, tragically ending in impact.
Further supporting this theory are:
-
Eyewitness reports of a loud bang
, possibly indicating an engine failure.
-
A
mayday call
reportedly made by the crew.
-
The
audible presence of the RAT
in the video, suggesting a complete loss of engine-driven electrical and hydraulic systems.
-
The
noticeable absence of typical engine noise
, supporting the hypothesis of dual engine failure.
In the meantime, my thoughts are very much with all those affected by this heartbreaking event.
( NOTE: Unfortunately this is my first post here. I wanted to upload the frame for all to see but the forum is restricting me from doing this until I reach 8 posts. I can't link to it via a URL either. I studied a frame from the very start of the video, just as the full aircraft enters view and expanded it by 400% allowing me to see the position of the MLG doors).
2 users liked this post.
2025-06-13T23:07:00
permalink Post: 11900986
Interested observer here, nothing more; with a question:
If the mayday call has been reported correctly, it states: \x91Mayday! No thrust. Losing power. Cannot lift.\x92
Is the term \x91Cannot lift\x92 standard comms for lack of climb rate/stall? If not, it strikes me that the transcript is incomplete, either due to loss of comms, inaudibility, or even just bad reporting.
\x91Cannot lift gear\x92?
If the mayday call has been reported correctly, it states: \x91Mayday! No thrust. Losing power. Cannot lift.\x92
Is the term \x91Cannot lift\x92 standard comms for lack of climb rate/stall? If not, it strikes me that the transcript is incomplete, either due to loss of comms, inaudibility, or even just bad reporting.
\x91Cannot lift gear\x92?
2025-06-13T23:21:00
permalink Post: 11900993
Combining all the bits and pieces of info from this thread so far, IMO we can theoretically sequence it thus using the video from the left:
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
4 users liked this post.
2025-06-14T00:52:00
permalink Post: 11901042
Couldn't agree more - never understood this - got to say, calling a mayday seconds into an event (particularly when still down in the dirt) does my head in - nobody is coming up to help. I think you need to keep the focus completely on the task at hand. In an emergency, external distractions destroy checklist SOPs, crew coordination etc etc - I try and keep ATC, company maintenance, etc etc disruptions out of the cockpit until everything is under control.
4 users liked this post.
2025-06-14T13:13:00
permalink Post: 11901471
Narrow body Airbus training Captain here, two comments:
From the thread it is assumed the Co-Pilot was Pilot Not Flying. Are we sure who was Pilot Flying and who was Pilot Not Flying? (Or whatever nomenclature Air India uses for those positions)
What is Air India’s cockpit culture. Does the Captain always fly the first leg of a trip? Are we sure the Mayday call was made by the Co-Pilot? (I would believe it was even if the Co-Pilot had made the takeoff as when everything went sideways the Captain most likely would have taken the controls)
Things went bad almost immediately after takeoff, ie at virtually the point where the airplane shifts from ground mode to flight mode. I am unfamiliar with the 787. Is there anything in the litany of the things which take place during that transition which could have malfunctioned to cause or contribute to this tragedy?
From the thread it is assumed the Co-Pilot was Pilot Not Flying. Are we sure who was Pilot Flying and who was Pilot Not Flying? (Or whatever nomenclature Air India uses for those positions)
What is Air India’s cockpit culture. Does the Captain always fly the first leg of a trip? Are we sure the Mayday call was made by the Co-Pilot? (I would believe it was even if the Co-Pilot had made the takeoff as when everything went sideways the Captain most likely would have taken the controls)
Things went bad almost immediately after takeoff, ie at virtually the point where the airplane shifts from ground mode to flight mode. I am unfamiliar with the 787. Is there anything in the litany of the things which take place during that transition which could have malfunctioned to cause or contribute to this tragedy?
2025-06-14T13:43:00
permalink Post: 11901497
Hello everyone. According to India Today, the last words of the pilot were "Thrust not achieved, falling, mayday".
2025-06-14T14:05:00
permalink Post: 11901513
I agree it is helpful to seek a consensus on some of these matters.
The most productive responses would be along the lines of:-
(1) I too have read all previous posts and agree that your summary reflects the current consensus,
(2) I too have read all previous posts and agree your summary reflects the consensus HOWEVER I challenge that consensus because... [ [i]EITHER (a) reference to previous post that merits greater credence, OR (b) new evidence supplied],
(3) I too have read all previous posts but I do NOT agree your summary reflects the consensus [explanation required].
It is not necessary for everyone who thinks (1) to say it (although some initial feedback would be useful!). However, if any of the more experienced and informed PPRuNers are thinking either (2) or (3) then it would be instructive to hear that.
FWIW, yours strikes me as a reasonable summary of the best consensus I have been able to discern (as of ~30 minutes ago). There are multiple caveats to each line item, but I presume you've deliberately left those out for the sake of readability, so I'll do the same!
The only comments I would add are:-
- It's a stretch to say the RAT is seen or heard "conclusively". Doubts have been expressed about the video quality and there are dissenting views regarding the audio. If a few more people were able to wade in on the audio point in particular, this could be very beneficial in moving the discussion forward because the presence or otherwise of the RAT is significant to several competing theories.
- On the subject of audio, I am surprised there has not been more discussion regarding engine noise. In the primary eye witness video the (alleged) RAT can be heard distinctly, as can the sounds of distant impact. If the engines were working as expected when overflying the camera and then flying directly away from it, do we really not think the engine noise would be more conclusive, i.e. louder (notwithstanding quiet engines and derated takeoffs)?
Whichever way readers are leaning in the flaps versus power loss debate, surely these two points are pivotal, and we have actual evidence available to discuss?
- Gear bogies: I'm not sure a consensus has yet been reached regarding the angle of the bogies. (I am not personally qualified to comment on this - I am purely saying I don't see a clear consensus just yet among those who are)
- Mayday call: I don't recall seeing a confirmed source for the widely reported mayday. Others have brought this up in the thread but nobody appears to be able to confirm one way or the other. If accurate, its contents are informative. Am I right to presume that you have left it out of your summary due to a lack of confirmation?
The most productive responses would be along the lines of:-
(1) I too have read all previous posts and agree that your summary reflects the current consensus,
(2) I too have read all previous posts and agree your summary reflects the consensus HOWEVER I challenge that consensus because... [ [i]EITHER (a) reference to previous post that merits greater credence, OR (b) new evidence supplied],
(3) I too have read all previous posts but I do NOT agree your summary reflects the consensus [explanation required].
It is not necessary for everyone who thinks (1) to say it (although some initial feedback would be useful!). However, if any of the more experienced and informed PPRuNers are thinking either (2) or (3) then it would be instructive to hear that.
FWIW, yours strikes me as a reasonable summary of the best consensus I have been able to discern (as of ~30 minutes ago). There are multiple caveats to each line item, but I presume you've deliberately left those out for the sake of readability, so I'll do the same!
The only comments I would add are:-
- It's a stretch to say the RAT is seen or heard "conclusively". Doubts have been expressed about the video quality and there are dissenting views regarding the audio. If a few more people were able to wade in on the audio point in particular, this could be very beneficial in moving the discussion forward because the presence or otherwise of the RAT is significant to several competing theories.
- On the subject of audio, I am surprised there has not been more discussion regarding engine noise. In the primary eye witness video the (alleged) RAT can be heard distinctly, as can the sounds of distant impact. If the engines were working as expected when overflying the camera and then flying directly away from it, do we really not think the engine noise would be more conclusive, i.e. louder (notwithstanding quiet engines and derated takeoffs)?
Whichever way readers are leaning in the flaps versus power loss debate, surely these two points are pivotal, and we have actual evidence available to discuss?
- Gear bogies: I'm not sure a consensus has yet been reached regarding the angle of the bogies. (I am not personally qualified to comment on this - I am purely saying I don't see a clear consensus just yet among those who are)
- Mayday call: I don't recall seeing a confirmed source for the widely reported mayday. Others have brought this up in the thread but nobody appears to be able to confirm one way or the other. If accurate, its contents are informative. Am I right to presume that you have left it out of your summary due to a lack of confirmation?
- The bogie could be explained by the Flap/Slat priority valve giving priority to the flaps if the PM suddenly realised his mistake and quickly put the flap lever back to the TO position and then selected the gear lever to UP. Those systems are both heavy hitters and would\x92ve sucked the life out of the CTR hydraulic system pumps.
- There is no way loss of AC (alleged RAT deployment) could've caused a spool down of both engines. Think QF A380 incident in SIN - The entire #1 engine wiring harness in the wing was completely severed and yet it continued (by design) to run at its previous thrust setting. They had to shut it down using a fire truck!
- History and design would dictate that a big 180 minutes ETOP\x92s twin such as the 787 having a dual engine failure or significant power loss at such a critical phase of flight would be a billion to one chance at best. Only the Airbus A400 had a software issue causing all 4 engine fuel shutoff valves to close causing it to crash killing the flight test crew - But this was during its development and flt testing.
- Wide body twin\x92s delivering in the region of 60,000 to 115,000 lbs of thrust at TO rarely , if at all, flame out from multiple bird strike(s) like the baby Bus\x92s and Boeing\x92s. If anyone has seen the frozen chickens at TO power video would know what I\x92m talking about. And the Fan Blade being \x91blown off\x92 as well. In both cases the engine was was able to maintain full TOGA thrust for significantly longer than the AI aircraft.
But it\x92s early days and anything could happen. And nothing surprises me anymore.
3 users liked this post.
2025-06-14T14:09:00
permalink Post: 11901517
Max EGzt and autorelight
Combining all the bits and pieces of info from this thread so far, IMO we can theoretically sequence it thus using the video from the left:
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
In-flight, the Autorelight function should attempt to restart the engine as soon as a flameout is detected, and for an engine flaming out at high power it might catch it before it even goes sub-idle. Generally, Autorelight will continue attempting until some cutoff N2 at which time it will stop attempting, or if the pilot move the fuel switch to Cutoff. And while the EEC is still powered (via its own PMA) down to roughly 10% N2, the ignition exciters required for Autorelight do get their power from the airplane.
2025-06-14T15:27:00
permalink Post: 11901573
https://www.theguardian.com/world/20...ay-authorities
Interesting to note that this report says pilot's mayday consisted only of 2 words "mayday, mayday", with no response to the ATC request for further reply. I have seen this quoted elsewhere now in mainstream media. I will leave others to formulate their own theories in response to this report. It seems popular to do so.
Interesting to note that this report says pilot's mayday consisted only of 2 words "mayday, mayday", with no response to the ATC request for further reply. I have seen this quoted elsewhere now in mainstream media. I will leave others to formulate their own theories in response to this report. It seems popular to do so.
1 user liked this post.
2025-06-14T15:35:00
permalink Post: 11901582
What concerns me a little bit is if indeed AC power is lost, would the suction feed inlets in the wing tanks provide enough fuel flow to maintain TO thrust?
I know the system is designed to achieve this in a situation where all of the AC powered boost pumps are lost. But what about in a real situation...
Could this cause a degradation of thrust? Even the slightest decrease..
And if the Captain(?) mentioned power loss in his Mayday. Was he referring to electrical power loss?
I know the system is designed to achieve this in a situation where all of the AC powered boost pumps are lost. But what about in a real situation...
Could this cause a degradation of thrust? Even the slightest decrease..
And if the Captain(?) mentioned power loss in his Mayday. Was he referring to electrical power loss?