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?
Subjects: Bird Strike Electrical Failure Engine Failure (All) FlightRadar24 Gear Retraction Mayday RAT (All) RAT (Deployment)
9 users liked this post.
2025-06-14T02:51:00
permalink Post: 11901095
I attempted a rudimentary timeline analysis of the two most prominent videos. Folks on here are usually far quicker & more adept than me at producing this type of analysis, so approach the following with due scepticism!
Please verify the videos using the links below, so we know we are all talking about the same thing. I deliberately avoid any judgment regarding theories posted thus far - I am merely supplying information against which you can further test those theories.
1. Primary eye witness video with audio:
[ X link ending 1933089931347345596 in case the hyperlink itself doesn't work for any reason]
- Footage starts with aircraft directly overhead, give or take, (based on both sound & vision)
- 13 seconds from start until fireball clearly visible above roofline
2. Airport CCTV:
[X link ending 1933162059556159903 ]
- 49-50 seconds until impact and fireball clearly visible
Subtract the 13 secs noted in video #1 and this establishes the approximate moment the aircraft passes over the video witness's position when viewed from video #2 (CCTV):
49 - 13 = 36 secs into video 2
Estimated timeline (CCTV #2):
19s: rotate
31s: climb rate noticeably deteriorates (12s after TO / 18s from impact)
36s: estimated moment aircraft overflies eyewitness camera (17s after TO / 13s from impact)
38-40s: pitch up then descent begins (19-21s from TO / 9-11s from impact)
49s: first contact with ground (30s after TO / approx impact)
50s: fireball visible above rooftops
Conclusions from combining both videos:
- Aircraft overflies eyewitness camera roughly 13 secs before impact
- This is well after it has stopped climbing (~6 secs)
- This is also mere seconds before CCTV shows the aircraft pitch up and start to descend (which I believe I can substantiate in the eye witness video, although this is tougher to confirm with the naked eye from this viewing angle - someone may have to look more closely than I can this evening!)
- I have previously asked questions about the audio in video #1 and whether we can draw any conclusions regarding RAT deployment & engine thrust. There are strong opinions on both sides. Your personal view on this will influence your evaluation of what the videos show, but either way your theory needs to fit the timeline (or advance a different one).
So, anyone who is developing a theory ought to consider whether it is consistent with the following:-
- rate of climb decays to 0ft/m within 10-12 secs of rotation
- RAT (possibly) audible within 17s of rotation *
- pitch up shortly afterwards with no discernible increase in engine noise & unable to arrest descent
- impact with ground within 30 secs of rotation
* I recognise that the RAT deployment is not an established fact, but any theory that proposes RAT deployment needs to take into account this timeline in addition to the rest.
Alternatively, you are welcome to refute this simplistic, late night analysis of the limited video evidence.
Please verify the videos using the links below, so we know we are all talking about the same thing. I deliberately avoid any judgment regarding theories posted thus far - I am merely supplying information against which you can further test those theories.
1. Primary eye witness video with audio:
[ X link ending 1933089931347345596 in case the hyperlink itself doesn't work for any reason]
- Footage starts with aircraft directly overhead, give or take, (based on both sound & vision)
- 13 seconds from start until fireball clearly visible above roofline
2. Airport CCTV:
[X link ending 1933162059556159903 ]
- 49-50 seconds until impact and fireball clearly visible
Subtract the 13 secs noted in video #1 and this establishes the approximate moment the aircraft passes over the video witness's position when viewed from video #2 (CCTV):
49 - 13 = 36 secs into video 2
Estimated timeline (CCTV #2):
19s: rotate
31s: climb rate noticeably deteriorates (12s after TO / 18s from impact)
36s: estimated moment aircraft overflies eyewitness camera (17s after TO / 13s from impact)
38-40s: pitch up then descent begins (19-21s from TO / 9-11s from impact)
49s: first contact with ground (30s after TO / approx impact)
50s: fireball visible above rooftops
Conclusions from combining both videos:
- Aircraft overflies eyewitness camera roughly 13 secs before impact
- This is well after it has stopped climbing (~6 secs)
- This is also mere seconds before CCTV shows the aircraft pitch up and start to descend (which I believe I can substantiate in the eye witness video, although this is tougher to confirm with the naked eye from this viewing angle - someone may have to look more closely than I can this evening!)
- I have previously asked questions about the audio in video #1 and whether we can draw any conclusions regarding RAT deployment & engine thrust. There are strong opinions on both sides. Your personal view on this will influence your evaluation of what the videos show, but either way your theory needs to fit the timeline (or advance a different one).
So, anyone who is developing a theory ought to consider whether it is consistent with the following:-
- rate of climb decays to 0ft/m within 10-12 secs of rotation
- RAT (possibly) audible within 17s of rotation *
- pitch up shortly afterwards with no discernible increase in engine noise & unable to arrest descent
- impact with ground within 30 secs of rotation
* I recognise that the RAT deployment is not an established fact, but any theory that proposes RAT deployment needs to take into account this timeline in addition to the rest.
Alternatively, you are welcome to refute this simplistic, late night analysis of the limited video evidence.
Subjects: CCTV RAT (All) RAT (Deployment)
13 users liked this post.
2025-06-14T15:41:00
permalink Post: 11901584
To me, it makes sense to focus on testing out theories that fit within the ambit of Murphy's Law. There is no way of knowing which of us will turn out to be right. Possibly none of us...
Subjects: None
1 user liked this post.
2025-06-14T16:17:00
permalink Post: 11901617
The assumption is often made that the witness must regularly find him/herself beneath the flight path and is therefore familiar with normal operations, but there is no particular reason why that should be the case. It could equally be their first time.
I usually think this but don't post it. " Why bother this time? " I hear you cry. Well, because (1) this time a question was asked (which I like), (2) the question actually has an answer, and (3) this is a timely example of Murphy's Law, which I referenced in another recent post.
Apparently, the boy who filmed it was visiting his father's rented flat for the first time and was thrilled at how low the aircraft were passing overhead. As I understand it, this is the very first one he attempted to film and he is utterly traumatised.
https://indianexpress.com/article/ci...ying-10066763/
Last edited by Pip_Pip; 14th Jun 2025 at 16:19 . Reason: typo
Subjects: None
9 users liked this post.
2025-06-14T16:44:00
permalink Post: 11901644
Subjects: Mayday
3 users liked this post.
2025-06-15T00:32:00
permalink Post: 11901994
The mayday reports are so unreliable / inconsistent that you simply cannot base any theory on these alone. It is best to focus on some other aspect at this time.
Some have questioned whether a solitary 'communication' was optimal, given the timings, circumstances and the prioritisation of aviation & navigation. I see both sides of that particular argument. But the idea of making a second call during a flight that was airborne for less than 30 seconds to repeat a mayday? I find that hard to believe.
Some have questioned whether a solitary 'communication' was optimal, given the timings, circumstances and the prioritisation of aviation & navigation. I see both sides of that particular argument. But the idea of making a second call during a flight that was airborne for less than 30 seconds to repeat a mayday? I find that hard to believe.
Subjects: Mayday
4 users liked this post.
2025-06-16T02:21:00
permalink Post: 11903062
As one of the two authors who have offered an acoustic analysis of the AI 171 'RAT' video here I feel obliged to make some observations.
First of all Kraftstoffvondesibel and I did our work completely without knowledge of each other. We reached the same conclusions more or less, most likely using different software (I used four different methodologies) and in subsequent discussions between us we've found our specific results (frequency etc) match very closely - including the doppler shift that we've also both commented on.
While this doesn't absolutely prove the RAT scenario (I was, at least initially, somewhat more circumspect on this matter as anyone reading my first post would find) it does go some distance towards reconciling our respective methodologies and outcomes. Given the confluence and discussion I am now more satisfied that the RAT was deployed than I was before - although for the reasons espoused earlier I totally recognise the [scientific] challenges to this view.
In this regard I too would not 'mind' if our view regarding RAT deployment were proven incorrect. What Kraftstoffvondesibel and I have done is simply use a little science and apply a quantitative analysis to the available data that many had qualitatively argued over. One might hope that, amongst other things, it could have dispelled the RAT/no RAT question to some degree and reduce thread noise, but unfortunately it seems some haven't read the thread through, or perhaps lack analytical reasoning.
This site isn't the place for a full academic paper+peer review and for me the real subject of this thread is the tragedy of AI 171 and what might determinable from what we know in the hope it will be useful to those closer to the coal face. If you are a physicist, scientist or engineer and have the capability then the same data we used is also available to you to do your own analysis. Should you do so we'd welcome hearing the outcome - whether it concurs with our results or not - as this is the scientific way. If you want to include the full nitty-gritty detail of how you've gone about then for a very small percentage of us that might be interesting, but it'd be peripheral to the main issue - and bear in mind that RAT deployment itself is merely an indicator of other potentially more serious issues. It is not likely to be the cause per se !
To conclude, I understand it's a long thread but as far as the RAT question is concerned, I'd encourage you to read the relevant posts at least and if you remain unconvinced, and you have the skills, then why not conduct your own analysis and let us know the results? Otherwise perhaps as a group we could move on from this, remembering that this is a terrible event which at the very least deserves informed useful discussion rather than wild and/or repetitive speculation.
FP.
First of all Kraftstoffvondesibel and I did our work completely without knowledge of each other. We reached the same conclusions more or less, most likely using different software (I used four different methodologies) and in subsequent discussions between us we've found our specific results (frequency etc) match very closely - including the doppler shift that we've also both commented on.
While this doesn't absolutely prove the RAT scenario (I was, at least initially, somewhat more circumspect on this matter as anyone reading my first post would find) it does go some distance towards reconciling our respective methodologies and outcomes. Given the confluence and discussion I am now more satisfied that the RAT was deployed than I was before - although for the reasons espoused earlier I totally recognise the [scientific] challenges to this view.
In this regard I too would not 'mind' if our view regarding RAT deployment were proven incorrect. What Kraftstoffvondesibel and I have done is simply use a little science and apply a quantitative analysis to the available data that many had qualitatively argued over. One might hope that, amongst other things, it could have dispelled the RAT/no RAT question to some degree and reduce thread noise, but unfortunately it seems some haven't read the thread through, or perhaps lack analytical reasoning.
This site isn't the place for a full academic paper+peer review and for me the real subject of this thread is the tragedy of AI 171 and what might determinable from what we know in the hope it will be useful to those closer to the coal face. If you are a physicist, scientist or engineer and have the capability then the same data we used is also available to you to do your own analysis. Should you do so we'd welcome hearing the outcome - whether it concurs with our results or not - as this is the scientific way. If you want to include the full nitty-gritty detail of how you've gone about then for a very small percentage of us that might be interesting, but it'd be peripheral to the main issue - and bear in mind that RAT deployment itself is merely an indicator of other potentially more serious issues. It is not likely to be the cause per se !
To conclude, I understand it's a long thread but as far as the RAT question is concerned, I'd encourage you to read the relevant posts at least and if you remain unconvinced, and you have the skills, then why not conduct your own analysis and let us know the results? Otherwise perhaps as a group we could move on from this, remembering that this is a terrible event which at the very least deserves informed useful discussion rather than wild and/or repetitive speculation.
FP.
Now, if you and Kraftstoffvondesibel wouldn't mind conducting similar audio analysis of a moped whizzing past, that might help to dispel one of the most popular competing theories.
I appreciate the time taken to produce information that might help us advance our understanding. I am not qualified to mark your homework, but I can recognise that you have spent time on it, shown your workings, and self-reported the limitations. That sets you apart (from some) and earns my respect.
(I just hope you haven't been proven wrong in the time it has taken me to post this...)
Subjects: Audio Analysis RAT (All) RAT (Deployment)
11 users liked this post.
2025-06-16T03:08:00
permalink Post: 11903073
Times (of London).
"A loss of engine power is emerging as the most likely cause of the crash of the Air India Boeing that killed at least 279 people at Ahmedabad on Thursday. The Boeing 787-8 series appeared to have suffered from lower than normal thrust from its General Electric GEnx engines as it took off and failed to climb more than 450ft before crashing, video and reports from the Indian authorities have indicated."
"A loss of engine power is emerging as the most likely cause of the crash of the Air India Boeing that killed at least 279 people at Ahmedabad on Thursday. The Boeing 787-8 series appeared to have suffered from lower than normal thrust from its General Electric GEnx engines as it took off and failed to climb more than 450ft before crashing, video and reports from the Indian authorities have indicated."
The story also says, "No cause has yet been identified for what would be an extremely rare power loss from both engines, but on Sunday the Indian civil air authority (DGCA) began urgent pre-flight inspections of fuel systems, electronic engine controls and other systems on Indian Boeing 787s."
And it quotes Juan Browne (Blancolirio): \x93There was something terribly wrong with this 787 jet and we need to find out really quickly what went wrong because we\x92ve got a thousand of these operating today and operators need to find out what happened.\x94
And it quotes Juan Browne (Blancolirio): \x93There was something terribly wrong with this 787 jet and we need to find out really quickly what went wrong because we\x92ve got a thousand of these operating today and operators need to find out what happened.\x94
Subjects: DGCA GEnx (ALL)