Posts about: "NTSB" [Posts: 28 Pages: 2]

Someone Somewhere
2025-06-12T12:34:00
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Post: 11899162
Originally Posted by Spunky Monkey
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.
787 gear and flaps/slats are both on the centre system, powered by 2x big electric pumps and no EDPs, so retraction should be minimally impacted by engine failure assuming electric power was still available and reconfiguration worked. Note the 787 has two generators per engine so generator failure is also unlikely to contribute, unless both engines failed taking out all four generators (and presumably no APU running).

Originally Posted by The Brigadier
Assuming we're not facing a repeat of the Boeing 737‑800 crash at Muan International Airport when loss of loss of both engines apparently also cut power to Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR)
From that thread, I believe it was discussed that on most/all other large transports, deploying the RAT re-powers the CVR/FDR. The 737 didn't have that happen because no RAT. You may still get a few second gap while the RAT deploys.

The 787 has 2x Enhanced Airborne Flight Recorders (EAFR), which each record both cockpit voice and flight data. I expect they are also fitted with the dedicated batteries that the Jeju was a year or two too early to require. Per the NTSB , the forward recorder has a 10-minute backup battery.

Hopefully flight data is not going to be an issue for this investigation.

Originally Posted by Sriajuda
Also, what is this discussion about the RAT? Unless someone has extremely quickly faked the audio on the video, it is pretty clear that the engines were running. (Both of them, there is some slight interference pattern I (maybe imagine) to hear.
The suggestion is that the buzzsaw/propeller sound is the RAT; it does sound a bit like an interference pattern, but you don't get the engine roar with it.

It's also maybe visible in a few stills (e.g. post 64).

Last edited by Someone Somewhere; 14th Jun 2025 at 06:01 .

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DaveReidUK
2025-06-13T11:17:00
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Post: 11900370
Originally Posted by The Brigadier
All to easy to surmise the contents will be tampered with at the request of politicians/investors
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.

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Tom Bangla
2025-06-13T11:37:00
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Post: 11900392
Originally Posted by DaveReidUK
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.
I believe and hope you're right, Dave. But don't be so quick to eliminate unorthodox business. India's a funny old country.
A0283
2025-06-14T16:41:00
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Post: 11901642
Originally Posted by AirScotia
I read that the 'AAIB' will be investigating. I presume that's AAIB (India)? Do we know what facilities the AAIB (India) has for reading FDRs?
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.
ATC Watcher
2025-06-14T17:03:00
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Post: 11901662
Originally Posted by A0283
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.
from the EASA statement yesterday :
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
​​​​​​​No mention of UK
OldnGrounded
2025-06-15T13:29:00
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Post: 11902475
Originally Posted by blind pew
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.
AA191. The NTSB report with probable cause was published within less than a year, IIRC. But it wasn't all that difficult to determine once they knew that forklifts were being used to R&R engines. In the 737 rudder hardovers, I think eight years passed between the first crash and a probable cause finding (in the second crash) that implicated the PCU servo. Of course, as someone has already posted, much more monitoring, data recording and transmission is available now in 21st century aircraft, although the accident aircraft in this case may not have transmitted much in the time available.

Last edited by OldnGrounded; 15th Jun 2025 at 13:37 . Reason: Typo. to not yo
Lord Bracken
2025-06-16T09:34:00
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Post: 11903315
Originally Posted by Icarus2001
My information differs to yours, We do know the EAFR was recovered on Saturday. Are you suggesting that it sat in a room for three days?
My expectation is that at the very least the AAIB (India) would want to open / read in the presence of the AAIB (UK) and the manufacturer. They might even want to read it at a location with specialist equipment (NTSB in Washington, BEA in France, AAIB in UK). None of this would be unprecedented when looking at previous accident investigations particularly for those that took place in developing countries.

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.
Pakistan A320 accident Karachi:

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.
(1st June was 10 days after the accident).

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Gino230
2025-06-17T00:58:00
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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!

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Lord Bracken
2025-06-17T18:13:00
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Post: 11904527
Originally Posted by cats_five
It took much more than a few days for the 737 Max to be grounded
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).

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DIBO
2025-06-17T18:54:00
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Post: 11904567
Originally Posted by Lord Bracken
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).
While reading this post, I was wondering whether the opening just last April and with much bravado (if I might say), of the brand-new, state-of-the-art FDR-lab and CVR-lab in Delhi, would not be an important 'political' factor deciding where the EAFR(s) are going to be processed.
An if they decide to do it locally, they will take their time (I hope) not to screw up their moment de gloire

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DaveReidUK
2025-06-17T19:03:00
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Post: 11904575
Originally Posted by Lord Bracken
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).
It isn't. It's essentially just a CVR and FDR in the same box. The main USP is that you now have two of each, about as far apart from each other as possible on the aircraft.

Each is downloaded separately in pretty much the same way as always.

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tdracer
2025-06-17T21:41:00
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Post: 11904694
Originally Posted by Lord Bracken
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.
Given the number of times I reviewed DFDR data supplied by an operator after some sort of event/incident, I think most major operators have access to the equipment needed to download a healthy data recorder. So I'd be a bit surprised if Air India does not have this capability. OldnGrounded has also posted that the Indian AAIB also has that ability.

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.

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Magplug
2025-06-18T10:17:00
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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.

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N8477G
2025-06-18T14:45:00
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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.

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OldnGrounded
2025-06-18T18:04:00
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Post: 11905429
Originally Posted by FullMetalJackass
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.
Emphatically yes. This is both correct and important to understand. The first rudder hardover crash, UA 585, was in 1991. The second, USAir 427, was in 1994. The first NTSB report concluding that the probable cause was the PCU servo was not issued until 1999, in the USAir investigation. As FMJ says, that only happened because the Eastwind 517 PCU servo issue resolved (what? spontaneously? independently?) and the crew was able to recover control and land safely. The whole story is fascinating, enlightening and sobering.

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.

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Gino230
2025-06-18T18:38:00
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Post: 11905461
Originally Posted by N8477G
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.
I didn't read that thread, but having flown the aircraft (challenger 600 type), I believe the consensus is that the Captain reaching underneath the thrust levers to actuate the flaps can (and has) resulted in the "triggers" on the back of the thrust levers being engaged- if this is done while the FO is bringing the thrust to idle, it can result in going below the idle stop to cutoff. In other words, the engines were inadvertently shut down.

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
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Post: 11905646
If:
  • Asiana can crash on approach and landing (Asiana 214)
  • Emirates can crash on a go-around (Emirates 521)
  • Emirates can almost crash on take off (Emirates 231)
  • United can almost crash on take off ( UA 1722)

Then Air India can have an accident on take off without any nefariousness or hidden design flaws.

This accident has the full attention of
  • Boeing
  • GE
  • FAA
  • NTSB
  • EASA

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.

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Seamless
2025-06-19T07:22:00
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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

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Musician
2025-06-20T12:13:00
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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.
Originally Posted by MaybeItIs
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.
Right. ADS-B is transmitted via radio, so reception can be patchy, or obstructed by someone else transmitting on the same frequency (e.g. other aircraft), so not every datagram that the aircraft sends gets received. When that happens, the live display of FR24 assumes the aircraft kept doing what it did, and when another datagram eventually comes in, it corrects the position. It also connects the locations of these datagrams, regardless of whether the aircraft actually went there. For example, in the AI171 there's a 4-minute gap between a datagram sent on the taxiway, and the next datagram sent when the aircraft was off the ground towards the departure end of the taxiway. FR24 then connected these points via the shortest route; but we know that the aircraft actually used the intervening 4 minutes to taxi to the approach end of the runway, where it then started its take-off run. So that was false. (Another source of errors is when different FR24 receivers don't have synchronised clocks, so a mixture of data from these can have weird artifacts as a result.)
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.
Have you ever seen a parabolic trajectory from "the short end"?
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.
Yes.

(The ADS-B data suggests the speed diminished 7% for ~50 ft of climb.)
Okay, didn't know that, I guess suggests means it's uncertain? Can you tell me from what height to what height it suggests this?
It's uncertain because the 787 rounds all altitudes it sends to the nearest multiple of 25. The altitudes sent were from 575 ft to 625 ft., but that's MSL and not adjusted for the weather: low air pressure makes that number higher than the actual altitude. FR24 adjusted this to 21ft climbing to 71 ft, but it could've been 30 to 60 or maybe 10 to 80, as it's rounded. I think it's fairly close to 50 feet of climb, though.

And why all the wrong figures for the height attained, quoted in previous thread? Can't all be the atmospheric conditions.
1) people taking the MSL altitude literally (625 ft)
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.
The survivor likened the sound to a car engine revving up. If you've listened to a good version of the phone video, you'll have noticed the "vroom" sound at the start that some likened to a motorcycle. That sound is the RAT in action, and you can imagine what that would sound like when it rapidly spins up: like a driver stepping on the throttle with their car engine in neutral.
If that's the case then what does that do to the possibility or otherwise that the TMCA system caused a dual engine shutdown?
The RAT deploying is a consequence of a dual engine shutdown. It says nothing about whether the TMCA was involved.

[Now I just hope your post is still there as I post this. ]

Last edited by Musician; 20th Jun 2025 at 12:26 .

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Musician
2025-06-22T07:24:00
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Post: 11908318
Originally Posted by compressor stall
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.
3. The AAIB looked into crew rostering; this is a routine part of air accident investigations (maybe not in India? but they have NTSB and UK AAIB sitting in this time). The AAIB found irregularities; this is a safety issue, so they notified the DGCA. The DGCA would've told Air India, "we can pull your operator license over this, but we won't if you fire those responsible".

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.)