Posts about: "NTSB" [Posts: 62 Pages: 4]

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).

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.

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).

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.

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 :
​​​​​​​No mention of UK

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.

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:

Pakistan A320 accident Karachi:

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

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!

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

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.

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.

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.

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.

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.

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??

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.

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

Thank you for your reply! There's a lot we agree on; unfortunately, I'll be cutting that from my response here.
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.

Have you ever seen a parabolic trajectory from "the short end"?
Yes.

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.

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.

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. 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. ]

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.)