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Screamliner
2025-06-15T15:11:00 permalink Post: 11902541 |
I'm reading a lot of the comments, speculation is something we all like, but some things just do not add up, even with a RAT deployed
if they had dual engine failure around 50 feet where you raise the gear, how can they still find the energy to climb, since they would be at VR/V2 speed (not V2+20 at that altitude, what VNAV would command after take off, especially with a take off weight of around 205/210 tons, the 787 wings are amazing but not miracles if they had a normal departure, why did they not raise the gear, they had a positive rate since they were climbing and the speed according to ADS-B was a constant. if they were single engine ! this would have saved them with this weight and weather, one of the first things you learn when EFATO with a 787, raise the gear, your climb performance increases dramatically Intersection take off can be ruled out: if they did an intersection departure with they're genex 64-70K engines, they would have had a take off limited weight of around 172 tons, I estimate that they were close to 205/210 tons, (max zfw of around 161 tons and around 45/50 tons of fuel) even full length would have been a stress for the engines, with the prevailing weather conditions, they would have never made it, full length is already difficult. When we see the video, the airplane is still climbing / flying straight and level (not losing altitude), yet we hear what we think might be the RAT, I can't imagine that they had the kinetic energy to do this with no engines. if they had dual engine failure, they would have been a brick, Hot and High, no thrust, flaps 5, zero chance. flickering of lights etc. seen by the survivor and the loud bang heard, I would not trust pax observations, because of the things they had to go through, also and I've said this before, if it was a loud bang, where is the smoke and fire in the engines, or in the video, its not audible lets see what the report will say, but it it could be a lot to swallow for some Last edited by T28B; 15th Jun 2025 at 16:30 . Reason: cleaned up formatting 1 user liked this post. |
triumph120
2025-06-15T16:52:00 permalink Post: 11902628 |
Retired aircraft engineer here, mostly military experience. Way back in this thread a contributor stated that he/she had heard the noise the RAT makes many times because Boeing regularly tested it in flight on production aircraft near to where they lived. Can someone tell us how the RAT is tested in flight? Is there a switch to manually deploy the RAT and. if so, could the RAT have been deployed by the crew in this way?
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StuntPilot
2025-06-15T17:09:00 permalink Post: 11902641 |
So it seems (after hours of reading), that the Almighty Prune has split into 3 camps, with each camp ignoring at least some evidence to the contrary, including that from actual experienced 787 pilots, test pilots, and engineers.
1. Incorrect flap / thrust settings / performance data / Autopilot management / general pilot error 2. Immediate, simultaneous thrust loss in both engines shortly after rotation 3. Crazy electrical / mechanical "theories" based on nonsense My head hurts. 1: Flaps were down 2: The RAT story is based on a single unsharp video frame. Earlier frames were much sharper but the RAT could not be seen (although there was a sound). 3. Lack of evidence I could be wrong, in that case please link QUALITY evidence so that we can learn something new. This way thousands of people are wasting countless hours. 6 users liked this post. |
sorvad
2025-06-15T17:19:00 permalink Post: 11902647 |
After hours of reading I conclude that so far nobody has the slightest clue about what happened.
1: Flaps were down 2: The RAT story is based on a single unsharp video frame. Earlier frames were much sharper but the RAT could not be seen (although there was a sound). 3. Lack of evidence I could be wrong, in that case please link QUALITY evidence so that we can learn something new. This way thousands of people are wasting countless hours. Last edited by sorvad; 15th Jun 2025 at 17:35 . 14 users liked this post. |
StuntPilot
2025-06-15T18:15:00 permalink Post: 11902683 |
Visual evidence the rat was deployed, audio evidence the rat was deployed, evidence the APU inlet door was open, evidence the gear retraction was interrupted, evidence there was very little engine noise after departure, very obvious evidence that the aeroplane didn\x92t have enough thrust to stop it descending into the ground. All of this strongly suggests that both engines were to all intents and purposes, and for want of a better word, \x91failed\x92 now that could be intentional, accidental or because of some sort of technical malfunction or external factor. Nothing conclusive and no answers as to how or why, but not quite as wildly stabbing in the dark as your post would infer.
2 users liked this post. |
Kraftstoffvondesibel
2025-06-15T18:25:00 permalink Post: 11902693 |
I realise the discussion has largely moved on, but for completeness I have analysed, filtered and compared the audio from several 787 videos\x97both take-off and landing (the latter with and without RAT deployment; take-off footage with the RAT out is rare).
Using the same style of frequency plots employed in the RAT analysis\x97and drawing on speed of different engine components data supplied by other contributors\x97it is straightforward to identify the engines\x92 high-power acoustic signatures objectively, despite variations among clips and the presence of Doppler shift. What is clear is that the engine noise in the recording bears no resemblance to a typical 787 take-off profile. Whether the engines were merely at very low thrust/idle or fully windmilling I cannot say with certainty, but they were certainly nowhere near take-off power. Make of that what you will. 40 users liked this post. |
fdr
2025-06-15T18:58:00 permalink Post: 11902721 |
The biggest news site in Greece claims to have the results of a kind of preliminary report from India AAIB which say that as the plane rotated, the pilot's seat malfunctioned (broken pin) and went suddenly far back forcing the captain to accidentally lower the thrust lever as he already had his hand on it and despite the co-pilots effort to help increase the thrust it was already to late to avoid the stall. I dont believe they would have posted something as serious as this without any credible source cause they are supposed to be a serious news outlet but you never know when stupidity takes over validity. Source is the protothema dot gr site
The proposition that is floated is that the pilot does not pull back on the control column, which he is holding onto with both hands as his seat slides backwards like a caricature of a bad Cessna 180 seat rail, that is plainly obvious from the pitch attitude of the aircraft, yet grabs lustily a double handful of thrust levers and holds onto those until meeting Ganesh in the next life? Greek papers appear to be as rigorous and incisive in their cognition as the Daily Telegraph. Golly. Seats: electric. RAT deployment... presumably the hapless pilot doesn't grab the control column, or the thrust levers, just grabs both fuel control switches instead???? Do any reporters bother to read what they write? 9 users liked this post. |
njc
2025-06-15T19:03:00 permalink Post: 11902726 |
![]() I'd phrase it differently: the frequency (and harmonics) of the noise are consistent with it being a RAT. If you then assume that it was a RAT and infer distance and speed curves from the Doppler variation, you get plausible values for an aircraft. But the two things are somewhat linked so you can't really treat the second thing as confirmation of the first. (FWIW, I'm personally quite satisfied that it was indeed a RAT on the audio.) 4 users liked this post. |
sorvad
2025-06-15T19:15:00 permalink Post: 11902740 |
We agree that there was a lack of thrust. Possibly caused by a dual engine failure. But the sharpest frames in the video do NOT show the RAT and this is counter evidence to the RAT theory. If there were substantial technical failures who knows what sounds could be generated. I find the evidence weak at best. And we immediately get into a chicken-egg problem: did some power issue of unknown nature cause an engine failure or did a dual engine failure occur, resulting in a power loss? Both are extremely unlikely and need to be backed by quality evidence. The video is not it, in my opinion. I don't know the APU intake mechanism and whether it could open after the impact.
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Stivo
2025-06-15T19:23:00 permalink Post: 11902745 |
I will wager that this is absolute nonsense. The effect of pulling the power levers back to idle at rotate would be readily countered by pushing them back up again. The engines are still delivering thrust, it is a function of N1, not the lever. The lever commands where the thrust level will end up, the N1 gives the thrust output. The acceleration/thrust characteristics of these engines is not like a J52 or JT3D etc.
The proposition that is floated is that the pilot does not pull back on the control column, which he is holding onto with both hands as his seat slides backwards like a caricature of a bad Cessna 180 seat rail, that is plainly obvious from the pitch attitude of the aircraft, yet grabs lustily a double handful of thrust levers and holds onto those until meeting Ganesh in the next life? Greek papers appear to be as rigorous and incisive in their cognition as the Daily Telegraph. Golly. Seats: electric. RAT deployment... presumably the hapless pilot doesn't grab the control column, or the thrust levers, just grabs both fuel control switches instead???? Do any reporters bother to read what they write? 2 users liked this post. |
limahotel
2025-06-15T19:24:00 permalink Post: 11902747 |
The biggest news site in Greece claims to have the results of a kind of preliminary report from India AAIB which say that as the plane rotated, the pilot's seat malfunctioned (broken pin) and went suddenly far back forcing the captain to accidentally lower the thrust lever as he already had his hand on it and despite the co-pilots effort to help increase the thrust it was already to late to avoid the stall. I dont believe they would have posted something as serious as this without any credible source cause they are supposed to be a serious news outlet but you never know when stupidity takes over validity. Source is the protothema dot gr site
1 user liked this post. |
DIBO
2025-06-15T19:29:00 permalink Post: 11902749 |
But the sharpest frames in the video do NOT show the RAT
and this is counter evidence to the RAT theory.
After hours of reading I conclude that so far nobody has the slightest clue about what happened.
1: ... 2: The RAT story is based on a single unsharp video frame. Earlier frames were much sharper but the RAT could not be seen (although there was a sound). 3. ... I could be wrong, in that case please link QUALITY evidence so that we can learn something new. This way thousands of people are wasting countless hours. This Pprune-forensic audio analysis (and subsequent posts) by Kraftstoffvondesibel, although completely ignored by many it seems, is the only clear proof there was a deployed RAT sound recorded in the young boy's video clip. You may disprove the analysis as much as you like, but referring to blurry video regarding possible RAT deployment or not, is indeed " thousands of people are wasting countless hours " I'm rather under the impression that many recent discussions are going backwards or h amsterwheeling. But thank you for your valuable audio analysis 5 users liked this post. |
sorvad
2025-06-15T19:34:00 permalink Post: 11902757 |
I've been sitting on my hands for days now...but please stop linking RAT deployment evidence with some blurry cluster of pixelation, which proves nothing.
This Pprune-forensic audio analysis (and subsequent posts) by Kraftstoffvondesibel, although completely ignored by many it seems, is the only clear proof there was a deployed RAT sound recorded in the young boy's video clip. You may disprove the analysis as much as you like, but referring to blurry video regarding possible RAT deployment or not, is indeed " thousands of people are wasting countless hours " I'm rather under the impression that many recent discussions are going backwards or h amsterwheeling. But thank you for your valuable audio analysis 3 users liked this post. |
Alty7x7
2025-06-15T20:23:00 permalink Post: 11902791 |
Engine failure with electrical power loss
We agree that there was a lack of thrust. Possibly caused by a dual engine failure. But the sharpest frames in the video do NOT show the RAT and this is counter evidence to the RAT theory. If there were substantial technical failures who knows what sounds could be generated. I find the evidence weak at best. And we immediately get into a chicken-egg problem: did some power issue of unknown nature cause an engine failure or did a dual engine failure occur, resulting in a power loss? Both are extremely unlikely and need to be backed by quality evidence. The video is not it, in my opinion. I don't know the APU intake mechanism and whether it could open after the impact.
Tdracer earlier confirmed that an airplane electrical power loss would allow engines to keep running , because 1) engines are fully-capable of suction feed operation in takeoff envelope (if boost pumps lost), and 2) the EECs are powered by their own PMAs when running and to substantially below idle (I recall roughly 10% N2). Airplane powers the EEC for ground starts, prior to PMA coming online, and as backup to the PMA after that. Related: Engine igniters are powered by the aircraft. So theoretical full loss of aircraft power would disable Autorelight upon a flameout. Ignitors typically don't make the cut for most-essential battery-only loads because it would also take an engine flameout, and the airplane past V1 in ground roll can fly fine on one engine that can achieve takeoff thrust. Autorelight is relevant - if there was a single-engine failure post V1, autorelight will attempt to relight the engine, so there is no need for a pilot to try to cycle the fuel switch to reset the EEC (potentially grabbing the wrong one), or to otherwise intervene. In such a circumstance, they need to trust their training. I've heard accounts that the most likely pilot instinct in such a situation would be to push the throttle(s) forward. Finally - there was talk earlier about accidentally cutting the fuel switches - and it was duly noted that they have to be pulled out over the detent, so very unlikely. The same cutoff effect could be achieved with the engine fire handle(s), right behind the fuel switches on the pedestal - though they are an upward pull, so also not subject to inadvertent or accidental engagement. |
Compton3fox
2025-06-15T20:52:00 permalink Post: 11902822 |
After hours of reading I conclude that so far nobody has the slightest clue about what happened.
1: Flaps were down 2: The RAT story is based on a single unsharp video frame. Earlier frames were much sharper but the RAT could not be seen (although there was a sound). 3. Lack of evidence I could be wrong, in that case please link QUALITY evidence so that we can learn something new. This way thousands of people are wasting countless hours. 7 users liked this post. |
Captain Fishy
2025-06-15T21:56:00 permalink Post: 11902882 |
Do not discount the mistaken early flap retraction scenario too easily. Mull on this:
PF commanded gear up on attaining positive rate of climb, fixating on the HUD. PM mistakenly raise flap lever from 5 to Flap 1 gate. Thrust reduced to Climb Thrust. Landing gear remained deployed. Massive loss of lift misidentified as loss of thrust. If any one pilot just had a dual engine failure scenario on a recent sim ride, brain and muscle memory would jump to loss of thrust in dual engine, prompting them to accomplish the recall memory items which called for both engine fuel control switches to CUTOFF and then RUN, and physically deployed the RAT. There would be immediate loss of thrust with the engine taking time to recover , if at all, at such low airspeed! The rest is left for Ppruners\x92 imagination.😖🥴😬 A loss of lift AND thrust at this critical juncture could have had caused this awful disaster. I think the data recorders have already revealed the cause but If it's this, then I don't think we will hear much anytime soon. |
Kraftstoffvondesibel
2025-06-15T22:06:00 permalink Post: 11902890 |
If you would read my post carefully you would know that my issue is that at the moment that the RAT is claimed to be heard and the plane is close the RAT is not seen in the frames. That comes much later when the plane is far away and pixelated. There is no ear witness. There is someone who claims to have heard hundreds of RAT deployments (not 500) and who has heard the audio. So yes, there is a brief RAT-like sound. But the evidence is too weak to base elaborate theories on.
Just putting this out there, since many might be unfamiliar with this, you included. 35 users liked this post. |
DIBO
2025-06-15T22:27:00 permalink Post: 11902910 |
But indeed, a lot of noise is being generated by some that continue to simply ignore the professional sound analysis provided already 600+ (surviving) posts ago, without any relevant counter-arguments or proof (other than some low quality video). (And I don't mind this sound analysis to be proven invalid, but then only with similar professional skills and counter arguments.) 5 users liked this post. |
First_Principal
2025-06-15T23:22:00 permalink Post: 11902953 |
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. 55 users liked this post. |
Kraftstoffvondesibel
2025-06-15T23:36:00 permalink Post: 11902967 |
Maybe you should describe your analysis then and present the data? I'm a physicist so chances are I might actually not be so unfamiliar. Please include an analysis of raw data quality, spectral resolution and binning as well. And don't state it is the 'exact same' as this is statistically impossible.
The latest techniques let us separate such things as reverbration from the source, when superimposing the reverberation/ambience and background noise of the AI crash urban environment on the clean, dead open field recording of the known B787 w/rat, they do indeed sound exactly the same to this very skilled and experienced listener. Although this is not courtesy of the computer analysis. It is just another angle of confirmation. All in all, i think this source audio is excellent. The source is an iphone, their mems based microphones, although noisy shows great spectral balance and is comparable to basic measurement microphones of professional application. There is plenty of information to analyse from in this sample. And again, I can't see it in the video either, and until I put on some really expensive headphones and fired up the software I was of a different opinion. I bowed to the science. Edit: I took an extra look, I am prepared to say the fall off at slightly above 16kHz is from the original recording, this is probably a limitation in the microphone, as it is not a hard cut-off before a 16kHz Nyquist frequency as it would be with a 32kHz sampling rate, there is dither noise from 16-20kHz fitting with the source being 16 bit. Last edited by Kraftstoffvondesibel; 15th Jun 2025 at 23:54 . 42 users liked this post. |
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