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Someone Somewhere
2025-06-12T12:34:00 permalink Post: 11899162 |
For an aircraft that will likely have TOGA pressed and be at a high power setting (plus the RAT deployed) it sounds awfully quiet.
Perhaps the gear was down because they knew they were going to force land due to lack of thrust. (Only a 738 driver), but the electric pumps to drive the hydraulics is much slower than the engine driven pumps and so flap selection / re-selection could be not as expected. RIP to all involved. The 787 has 2x Enhanced Airborne Flight Recorders (EAFR), which each record both cockpit voice and flight data. Hopefully flight data is not going to be an issue for this investigation. It's also maybe visible in a few stills (e.g. post 64). Last edited by Someone Somewhere; 14th Jun 2025 at 06:01 . 2 users liked this post. |
DaveReidUK
2025-06-13T11:17:00 permalink Post: 11900370 |
AFAIK , both the NTSB and UK AAIB are by now onsite to assist the investigation at the request of the Indian AIB. The suggestion that they wouldn't notice, or would be party to, funny business with the flight recorders is ridiculous. 14 users liked this post. |
Tom Bangla
2025-06-13T11:37:00 permalink Post: 11900392 |
I think the word you are looking for is "inconceivable".
AFAIK , both the NTSB and UK AAIB are by now onsite to assist the investigation at the request of the Indian AIB. The suggestion that they wouldn't notice, or would be party to, funny business with the flight recorders is ridiculous. |
A0283
2025-06-14T16:41:00 permalink Post: 11901642 |
reported were India AAIB with support from NTSB, earlier report was about UK AAIB ref the 50 plus UK passengers, other report mentioned Boeing and GE supporting.
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ATC Watcher
2025-06-14T17:03:00 permalink Post: 11901662 |
The investigation is being led by the Aircraft Accident Investigation Bureau (AAIB) of India in accordance with ICAO Annex 13. The U.S. National Transportation Safety Board (NTSB) as the respective State of Design for the aircraft and engines is expected to participate
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OldnGrounded
2025-06-15T13:29:00 permalink Post: 11902475 |
World wide grounding of the DC10 fleet after Chicago where maintenance had modified engine removal procedures which led to a wing engine loss taking out hydraulic systems that allowed the slats to retract ..aircraft stalled asymetrically and rolled inverted. Many other aircraft had damaged mounts/bolts not all were reported.
Last edited by OldnGrounded; 15th Jun 2025 at 13:37 . Reason: Typo. to not yo |
Lord Bracken
2025-06-16T09:34:00 permalink Post: 11903315 |
Quick example, EK 521 accident in DXB:
1.11 Flight Recorders The Aircraft was equipped with a Honeywell sold-state flight data recorder (SSFDR) and an L-3 Communication cockpit voice recorder (CVR). Both flight recorders were found mounted in their original locations on the Aircraft, with external signs of prolonged exposure to elevated temperatures. However, temperature indicators within each crash-survivable memory unit indicated that the memory components themselves had not been exposed to significantly elevated temperatures. The flight recorders were sent to the Air Accidents Investigation Branch (AAIB) facility in the United Kingdom for data retrieval in the presence of the Investigation Committee.
1.11. Flight Recorders 1.11.1. The aircraft was equipped with solid-state DFDR and solid-state CVR. DFDR and CVR were recovered from the accident site and taken to BEA, France by Investigator In-charge (IIC) from AAIB, Pakistan on 1st June, 2020. Despite having crash and heat effects, both recorders were successfully downloaded by BEA experts.
4 users liked this post. |
Gino230
2025-06-17T00:58:00 permalink Post: 11903898 |
Greg Feith, former NTSB chief investigator, stated on his personal Facebook page yesterday that he has reliable information from an impeccable source stating that the flaps were extended. He stops short of saying they were in the correct position, but one would imagine he has some knowledge of people on scene. Just another piece of info to chew on.
I've had two theories personally and both now seem wrong so I'm keeping any of my opinions to myself! 3 users liked this post. |
Lord Bracken
2025-06-17T18:13:00 permalink Post: 11904527 |
Absolutely. This confidence that the EAFR has already been read is misplaced. It\x92s a specialist piece of equipment and probably can\x92t even be downloaded in India. It\x92s most likely on its way to the NTSB, the BEA or the AAIB (UK) for analysis which will be done under strict conditions (for obvious reasons).
2 users liked this post. |
DIBO
2025-06-17T18:54:00 permalink Post: 11904567 |
Absolutely. This confidence that the EAFR has already been read is misplaced. It\x92s a specialist piece of equipment and probably can\x92t even be downloaded in India. It\x92s most likely on its way to the NTSB, the BEA or the AAIB (UK) for analysis which will be done under strict conditions (for obvious reasons).
An if they decide to do it locally, they will take their time (I hope) not to screw up their moment de gloire 5 users liked this post. |
DaveReidUK
2025-06-17T19:03:00 permalink Post: 11904575 |
Absolutely. This confidence that the EAFR has already been read is misplaced. It’s a specialist piece of equipment and probably can’t even be downloaded in India. It’s most likely on its way to the NTSB, the BEA or the AAIB (UK) for analysis which will be done under strict conditions (for obvious reasons).
Each is downloaded separately in pretty much the same way as always. 5 users liked this post. |
tdracer
2025-06-17T21:41:00 permalink Post: 11904694 |
I was referring to CVR/FDRs in general being specialist equipment requiring specialist facilities to process. In any case, I would be very interested to find out where those from this accident are read. It appears from a post upthread there are new facilities in New Dehli that could be used. Having said that, for the EK 521 accident in Dubai the recorders were sent to the UK for analysis, despite a "flight data recorder centre" in Abu Dhabi being opened (again with much fanfare) by the UAE GCAA five years before the occurrence.
Usually when I hear of data recorders going back to the US NTSB or the recorder manufacturer, it's because the crash damage is such that specialized equipment is needed to download the data. The recorder in the tail would likely have little damage. While the AAIB may have held off on downloading the recorders until all the major players are present, it's been several days - I'd expect everyone who matters is already there. So I think it is reasonable to believe that the investigators have done a download and have had at least a preliminary look at the data. If there is a smoking gun, they probably already know (and the longer we don't hear something regarding the rest of the 787 fleet, or at least the GEnx powered fleet, the less likely it is that they suspect a systemic problem with the aircraft and/or engine). However the proviso that I posted earlier about potential data loss/corruption due to a sudden shutdown still applies - so maybe the data simply isn't on the recorder. As has already been posted, EMI is highly unlikely - the current cert requirements for HIRF are quite high, and due to the composite airframe construction of the 787, the lighting requirements are much higher than for conventional aluminum aircraft (the higher resistance of the composite airframe results is higher lightning induced currents). FDR has suggested a large slug of water hitting critical aircraft electronics at rotation - it is possible that resultant electrical short circuits could falsely signal the engines that the switches are in cutoff. Highly unlikely that it would do that to both engines, but possible. Then again, all the other plausible explanations are highly unlikely, so... BTW, I do have a life outside PPRuNe - and I'm going to be traveling the next several days, with limited to non-existent internet access. So don't be surprised if I'm not responding posts or PMs. 16 users liked this post. |
Magplug
2025-06-18T10:17:00 permalink Post: 11905107 |
Boeing will safeguard Boeing's interests, the NTSB will safeguard American interests. If the Indian AAIB start dragging their feet over publishing their initial report in an effort to protect Indian interests then Boeing and the NTSB will make a joint press release to the effect that the aircraft was serviceable right up to the point of impact. They have done it before.
4 users liked this post. |
N8477G
2025-06-18T14:45:00 permalink Post: 11905301 |
Think bigger
Think about this accident from 100,000 feet. In other words, DON\x92T think about the specific root cause. We have almost no factual information to ponder at the moment but we can still ask a larger question: How did an experienced crew in a modern aircraft find themselves in a situation from which there apparently was no escape? Given the redundancies, fault tolerances, crew training, and engineering and operational controls present in modern aviation, how could it be that they happily took off in an airplane and flew it into an unsurvivable event just moments later?
This isn\x92t the first one either. On February 9, 2024 a Challenger 600 manuevering to final at Naples FL, (APF) lost both engines simultaneously and crashed on a highway short of the runway. The NTSB final report isn\x92t out yet so we don\x92t know that cause either, but the situation was the same. SOMEhow, a highly experienced crew found themselves in a situation from which there was apparently no escape. Whatever the cause was, how did it go un-detected until it produced an accident? (It\x92s NTSB accident number ERA24FA110. You can find that thread on PPRUNE by searching on Challenger 600. The preliminary NTSB report contains interesting readouts from the FDR. Yes, they lost both fans simultaneously.) I\x92m not suggesting these two accidents have related causes, I\x92m only observing that both crews apparently had no way out. I\x92m asking, \x93Whatever the flaw was that initiated these events, how did it remain un-known *until* it produced an accident?\x94 We test and re-test modern aircraft for every imaginable failure mode during the design, certification, and production process. We train and re-train techs, mechanics, flight crew, and everybody else that touches the airplane to be sure a high level of performance and safety is not compromised. Think bigger. Think about \x93the system\x94 as a whole. Apparently the system missed something. What are we not seeing? My condolences to all who were lost. Please keep in mind that except by the grace of God it could have been any one of us on that terrible day. NASA retired, licensed since 1971. 18 users liked this post. |
OldnGrounded
2025-06-18T18:04:00 permalink Post: 11905429 |
Do you recall the issue with the hydraulic PCU in 737s?. If you don't, they had a design flaw which led to the loss of two 737s including crew and passengers and even then, it took YEARS before the root cause was identified.
The time between the introduction of the 737-200 and the first crash due to the rudder reversal was around 24 YEARS. Then it was another 3 years until the second repeat occurrence which led to another crash. And only after another incident happened in yet another 737 in 1996 where the crew were able to land their stricken craft and tell the tale, could they finally identify the root cause. This is the first crash / hull loss of the 787. Taking the design flaw of the Boeing 737 as a baseline and the time taken to identify it, to claim that "if there was a design fault, we'd know about it" is premature, to say the least. Sometimes it's really, really difficult to determine the cause(s) of a catastrophic failure of a complex system and it may take a long time. 8 users liked this post. |
Gino230
2025-06-18T18:38:00 permalink Post: 11905461 |
This isn’t the first one either. On February 9, 2024 a Challenger 600 manuevering to final at Naples FL, (APF) lost both engines simultaneously and crashed on a highway short of the runway. The NTSB final report isn’t out yet so we don’t know that cause either, but the situation was the same. SOMEhow, a highly experienced crew found themselves in a situation from which there was apparently no escape. Whatever the cause was, how did it go un-detected until it produced an accident? (It’s NTSB accident number ERA24FA110. You can find that thread on PPRUNE by searching on Challenger 600. The preliminary NTSB report contains interesting readouts from the FDR. Yes, they lost both fans simultaneously.) I’m not suggesting these two accidents have related causes, I’m only observing that both crews apparently had no way out.
My condolences to all who were lost. Please keep in mind that except by the grace of God it could have been any one of us on that terrible day. NASA retired, licensed since 1971. But I agree that the complete, simultaneous loss of thrust on both engines has to be an astronomical probability, and the cause is going to be interesting to say the least. I also agree that any one of us could be put in a horrible position within seconds that would be very hard to recover from- the older I get and the more hours I spend in the air, this starts to spend more time in one's consciousness, unfortunately. BTW calling the crew " highly experienced" is a bit of a stretch IMO, the Captain certainly was, but 1100 hours isn't even enough for an ATP in most countries. For all we know it was not a factor, of course. PS, what is an SLF?? |
B2N2
2025-06-19T01:04:00 permalink Post: 11905646 |
If:
Then Air India can have an accident on take off without any nefariousness or hidden design flaws. This accident has the full attention of
1,189 Dreamliners have been delivered. There have been no worldwide or even regional groundings. No Emergency AD\x92s, no required inspections. If a hidden hardware or software issue would be suspected there would have been a response by FAA/EASA already. The silence is deafening\x85and telling. 6 users liked this post. |
Seamless
2025-06-19T07:22:00 permalink Post: 11905790 |
There seem to be issues with the evaluation due to damages. Cannot assess the reliability of the source.
https://weeklyvoice.com/damaged-blac...medium=twitter
The black box from the Air India flight AI171 that crashed in Ahmedabad on June 12 has been found damaged and may need to be sent to the United States for further data retrieval, according to government sources. Officials indicated that the final decision will rest with the Indian aviation authorities, but the device could be flown to Washington DC for evaluation by the U.S. National Transportation Safety Board (NTSB).
Technically, the “black box” includes two crucial components: the Cockpit Voice Recorder (CVR) and the Flight Data Recorder (FDR). These devices are essential for reconstructing the events leading up to the crash, offering both voice recordings from the cockpit and a detailed record of the aircraft’s flight parameters. Due to damage sustained in the crash and fire, India may require the specialized equipment and expertise of the NTSB to recover and interpret the remaining data. If the device is sent abroad, a team of Indian officials is expected to accompany it to ensure compliance with all security and procedural standards throughout the process. Last edited by Senior Pilot; 19th Jun 2025 at 08:19 . Reason: Add quote; please don’t just post hyperlinks 1 user liked this post. |
Musician
2025-06-20T12:13:00 permalink Post: 11906909 |
Flightradar24 and ADS-B
Thank you for your reply! There's a lot we agree on; unfortunately, I'll be cutting that from my response here.
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Sure, actual data is usually more accurate than eyeballed stuff. But not always. In fact, it's often the eye that determines that something measured or calculated is "Off". How accurate is ADS-B data? I've seen FR24 tracks go way off course then suddenly get corrected / interpolated, frequently. The erroneous data seems to be "removed" by their algorithm, but where are the errors arising? Why this inaccuracy, and therefore, how accurate are the datagrams referred to? I know there were no datagrams received during the backtrack that I accept actually occurred, but that's completely different from receiving erroneous ADS-B data.
However, the datagrams that FR24 actually received were correct. They contain the GPS position of AI171 and its unadjusted barometric altitude, as determined by its onboard instruments. This data is as reliable as the instruments themselves are. (An example here is that the NTSB wasn't sure that the altimeter on the Blackhawk that crashed at Washington-Reagan was accurate; if that is the case, the ADS-B data would also be affected.) On their blog post at https://www.flightradar24.com/blog/f...rom-ahmedabad/ , FR24 have published the data that they actually received.
Sure, the CCTV footage I've seen is very poor, a video, moved about and zoomed, of the CCTV screen. Not easy to judge, but still useful and could be analysed frame-by-frame to compensate for all the extraneous input. Anyway, it's obvious to me that the rate of climb dropped abruptly just before the flight attained its apex, as if thrust was suddenly cut off.
Knowing the momentum to altitude conversion, it might be possible to estimate whether that's true or not. The evident RAT deployment supports engine shutdown, not just engines to Idle, doesn't it? In that case, it would be useful to know at what altitude the engine shutdown took place.
(The ADS-B data suggests the speed diminished 7% for ~50 ft of climb.)
And why all the wrong figures for the height attained, quoted in previous thread? Can't all be the atmospheric conditions.
2) people adjusting for airport elevation (189 ft), but not for pressure: 437 ft 3) people adjusting for pressure, some adjusting for temperature, get 71 to ~100 feet for the last recorded altitude. But while ADS-B reception was lost then (or the transmitter lost power), the aircraft continued climbing; examine the cctv video, knowing the wingspan is ~200 feet, we see that the aircraft reached 200 feet but not much more.
One fact that alters things substantially is whether the survivor's impression is correct that possibly the engines started to spool up again just before impact.
If that's the case then what does that do to the possibility or otherwise that the TMCA system caused a dual engine shutdown?
[Now I just hope your post is still there as I post this. ![]() Last edited by Musician; 20th Jun 2025 at 12:26 . 3 users liked this post. |
Musician
2025-06-22T07:24:00 permalink Post: 11908318 |
It's either 2 things....
1. That happens from time to time and its the way things are done in India and it's only newsworthy now by association (not causation), or 2. The DGCA need to be seen to be doing something, and that's some low hanging fruit in an otherwise vacuum of information. It's a speculation, but I'd be surprised if it didn't fit the facts. Also, we can't draw any conclusions about the accident crew; the discovery could've been incidental, or the accident crew might be affected, but the investigation is ongoing, so that's not public yet. It will be in the report, perhaps in the preliminary report even. (I expect NTSB and UK AAIB insist on a preliminary report, but who knows.) |