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

SLF here. Mods - please delete summarily if this does not contribute to the discussion, I have no wish to waste anyones time. No 'AI' was used in the preparation of this post.

My understanding is that, as you say, the CAM has a preamp. That preamp can be powered by the RIPS that accompanies the forward EAFR.
In addition, I believe there is a single analogue connection from the CAM+preamp to the aft EAFR in addition to the analogue connection from the CAM+preamp to the forward EAFR. I believe, but am not sure,that the other flight-deck audio (headsets) is carried digitally over the fibre-optic network to the aft EAFR. The network may or may not be in operation in the event of an electrical failure: I simply don't know.

The publicly available information I can find is not stunningly clear about this.

AEROSAFETY WORLD, January 2008 - https://flightsafety.org/asw/jan08/a...47-48.pdf?dl=1

GE Aviation: Consolidate and increase recording power with the 3254F EAFR. - https://www.geaerospace.com/sites/de...rder-3254F.pdf

As for power, this NTSB document describes the power set-up for the EAFRs

https://data.ntsb.gov/Docket/Documen...ort-Master.PDF

So the forward EAFR is powered from the left 28V DC bus with the possibility of being powered by the RIPS, and the aft EAFR is powered from the right 28 V DC bus.

What I have been unable to determine is whether the right and/or left 28 V DC buses are powered from the main battery in case of failure of the AC power supply. To my untrained eye, it looks like the Captain's flight displays are powered from the main battery in extremis (28 V DC - C1), but that there are various circuit breakers, that could be automated, that may or may not allow or prevent other loads (such as the F/O's flight displays (28 V DC - C2), or the aft EAFR, being supplied by the main battery, (See link to diagram). There could well be very drastic automated load shedding.

https://kb.skyhightex.com/wp-content...l-1024x640.png

If the right 28 V DC bus was unpowered for any period, it follows that the aft EAFR was not recording for that period. This would make the forward EAFR important in case of a power failure that prevented the right 28 V DC bus from providing power.

All the information that is unclear to me will be transparently clear to the crash investigators. But it seems to me that the aft EAFR will not hold data for any period that the right 28 V DC bus is not operating. Whether that applies to this incident is an open question.

I am starting to see the hamsterwheel references now.
Having two combined recorders is already more backup than what had previously been the norm, in addition theres the independently powered area mic going analog to the front recorder.

The common models I have checked the sheets for also provides a digital output (which is probably sent to the aft recorder via normal busses.

Having a seperate analog line going to the aft recorder would be several Kg of extra weight, and probably a substantial amount of loom design and paperwork for what is then a backup to an already redundant system.

Hence, imho why this signal only goes to the forward recorder. It is already a \xabbonus\xbb.

The power for microphone and preamp is in the >1watt range range, completely insignificant.

I am still interested in reliable information as to what is expected to be on the recorder of an aircraft which has lost the generators, what about the battery powered prinary instruments? Does some systems and the aft recorder come online with the RAT or would everything be down to the one cockpit mic? Surely not?

https://www.pib.gov.in/PressReleseDe...x?PRID=2139785

Status Report on recovery and examination of data from Black Boxes – Air India Flight AI-171

Note the front EAFR is the one with RIPS battery backup.

The June 30, 2025 edition of Aviation Week & Space Technology (reviewed from an email with "Editors' Picks" sent to subscribers) includes an article dated June 27 by Sean Broderick, about the investigation of Air India 171. It relates some new facts or factual infomration (as well as coverage of many facts in the public domain for some time already).

One theme of the article is that the timing of release of information, in general about the investigation and specifically about data discovered in the recorder(s), appears inconsistent with other facts about the investigation. In support of this theme, the AW&ST article quotes a former NTSB investigator (with specific aircraft accident investigation experience).

The article also refers to the progress of work at the accident site (including an estimate of the number of workers involved) and the presence of aircraft accident investigation professionals from highly experienced authorities and entities (U.S. NTSB, U.K. AIB, Boieng, GE). It is pointed out - certainly with respect and diplomatic tone - that the aircraft accident investigation authority of India has relatively less experience in such matters. And that the presence of more experienced participants in the investigation (as accredited representatives, if I hopefully recall study of Annex 13 correctly) would suggest that guidance to the India authority has been available.

As the foregoing suggests the article asserts, in a thematic sense, that the timing of information release is not consistent with factual information about the investigation. (It also generally suggests that information typically is released by investigation authorities earlier within the initial 30-day time period provided for by Annex 13 .... but that generalization, while true in some cases, isn't backed up with anything specific of a factual nature.)

Mods, I hope this adds to the thread and if not please don't miss the bin when it gets tossed.

In keeping with PilotDAR's request, here is some possibly useful information regarding the type of Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) likely installed in the Air India B787 (using long names etc for those who may be unfamiliar with various acronyms).

The B787 was one of the first aircraft to receive a new type of FDR/CVR, known as an Enhanced Airborne Flight Recorder (EAFR). Some detail of the time may be found here:

https://www.flightglobal.com/boeing-.../67970.article
https://www.militaryaerospace.com/po...for-boeing-787

I don't believe it's absolutely confirmed yet but earlier posts (thank you V1... Ooops et al ) indicated that the unit in question may be a GE Aviation Model 3254F, the document here gives some good detail, along with another doc from Skybrary that has some relevant information.

And this one discusses more on the 'new' ARINC-767 protocol in use with these later units.

Some broader background into ARINC's role in determining the standards applicable to aviation can be seen in this video. While it doesn't specifically cover ARINC-767 (used by the B787 EAFR) the history and associated detail is interesting and may give a little useful background:




In terms of actual data recovery I had a look around but couldn't find any video that showed this from an EAFR, however this NTSB YT link gives insight into how data was recovered from an earlier FDR unit (mounted in a Bombardier CRJ700 ). While it's different to that installed in the 787 the nature of the work and how it's carefully carried out may give some insight.




Finally, this is a link to a short report re data recovered from an EAFR in a B787-9:

https://data.ntsb.gov/Docket/Documen...ort-Master.PDF

I claim no specific knowledge here, just providing references to detail I read while trying to learn more about these newer units.

FP.

I am not certain on that. Remember the 737 didn't have them on the standby bus (Jeju). The NTSB doc states they're powered from the L/R 28VDC buses on the 787.



This shows the centre TRUs can only power the instrument buses not the L/R DC buses, the RAT can't really power the right TRU without powering both R1/R2 buses, and powering the left TRU would require powering the left 235/115 ATU which would probably be a lot of magnetising current even if not much actual load. The contactor naming supports that.

My money is on the L/R DC buses being unpowered in RAT operation; only the CA/FO instrument buses and the 235VAC backup bus.

That's exactly why I would really recommend reading through the NTSB FDR report on the 2013 JA829J Boston incident helpfully posted by EDLB . There's potentially a wealth of data concerning a to me at least surprisingly number of 2000 of parameters written on a 787 EAFR, that is that at least if there's elec power. Even the 10 min RIPS is useless if there's no data sent from electrically shut off systems.

Link to the NTSB Report to which D Bru refers, (@EDLB goes to member’s profile):
Auxiliary Power Unit Battery Fire Japan Airlines Boeing 787-8, JA829J Boston, Massachusetts January 7, 2013

What are you talking about? Sources have already leaked information. NTSB (USA), AAIB (UK) and ICAO have sent people who have access, not to mention the aircraft and engine manufacturers. There's going to be a final report in about a year, and when that's out you can complain. (There has been precedent for a national accident board making a release about an investigation when the official report came up short, but I don't remember the details.) The ICAO-prescribed process is designed to produce this kind of participation, because air safety can't be a political issue.

- fuel cut offs were found in the RUN position

- on take off roll both engines lost power as the fuel cut offs went from RUN to cutoff

- CVR recorded one pilot asking why they had gone to CUTOFF

- within 10 seconds the fuel cutoff was moved back to RUN

-RAT was deployed, APU had begun auto start

- 32 seconds after Vr the MAYDAY was called



This should also dispel a lot of the comments about AAIB-India, Indian culture in general and general competence. For a preliminary report this is far more thorough and extensive than what would normally be expected and they\x92ve kept Boeing, GE, FAA and investigators from US, UK, Canada and Portugal in the loop from the start



They have also clarified why it took so long to do the EAFR download- because of the extensive damage they had to source specialist equipment from the NTSB that only arrived on the 23rd of June (they downloaded on the 24th) so all that talk of a \x91coverup\x92 is pretty embarrassing now

of course the big question is why/how those switches were commanded into cutoff in the first place the exact sequence at Vr is the most critical, there hasn\x92t been much scrutiny at all that I can see in the Indian/international media of the personal
background of the flight deck crew which has happened in other suspected pilot initiated disasters in the past, I guess this is an avenue investigators will have been doing themselves

SLF. But I've read in full both original threads and this thread.

The Preliminary Report is written in excellent English, so I think one should pay close attention to what it says.

One thing I noticed is that at the bottom of P4 NTSB are stated as "..participated in the investigation". However UK AAIB are only stated as "visited the site". My reading is that UK AAIB are not participating?

Another is that some items on the timescale are v precise, others much more vague.

A question :

If the fuel switches were moved to cutoff, for whatever reason, what exactly would each pilot see as an EICAS warning. I'm still unclear why one pilot asked the other why he cut off - actual observation of the action, or message.

There are indeed, in the United States, rather strict prohibitions and limitations on the availability of CVR transcripts as well as recordings under federal statutory law.

First, the NTSB is subject to strict statutory limits (See 49 U.S.C. Sec. 1114 - "Disclosure, availability and use of information"; 1114(c) "Cockpit recordings and transcripts":

1114(c)(1) Confidentiality of recordings.\x97
Except as provided in paragraph (2), the Board may not disclose publicly any part of a cockpit voice or video recorder recording or transcript of oral communications by and between flight crew members and ground stations related to an accident or incident investigated by the Board.

(2) Exception.\x97Subject to [certain exceptions] the Board shall make public any part of a transcript, any written depiction of visual information obtained from a video recorder, or any still image obtained from a video recorder the Board decides is relevant to the accident or incident\x97
(A)if the Board holds a public hearing on the accident or incident, at the time of the hearing; or
(B)if the Board does not hold a public hearing, at the time a majority of the other factual reports on the accident or incident are placed in the public docket.

So there are strict limits, although NTSB may exercise discretion - but I would argue that the default setting is non-disclosure, given the policy imperatives both stated and implied by this section:

1114(b)(3) Protection of Voluntary Submission of Information.\x97
Notwithstanding any other provision of law, neither the Board, nor any agency receiving information from the Board, shall disclose voluntarily provided safety-related information if that information is not related to the exercise of the Board\x92s accident or incident investigation authority under this chapter and if the Board finds that the disclosure of the information would inhibit the voluntary provision of that type of information . (emphasis supplied)

And by experience, Board has been quite discreet about disclosures of recordings... I hope I recall this correctly and await any necessary corrections.

What about in court?

49 U.S.C. Sec.1154 - "Discovery and use" of recordings and transcripts

(a)(1) Except as provided by this subsection, a party in a judicial proceeding may not use discovery to obtain\x97
(A) any still image that the National Transportation Safety Board has not made available to the public under section 1114(c) or 1114(d) of this title;
(B) any part of a cockpit or surface vehicle recorder transcript that the National Transportation Safety Board has not made available to the public under section 1114(c) or 1114(d) of this title; and
(C) a cockpit or surface vehicle recorder recording . (emphasis supplied)

The exceptions (crunching down to the essence of their application) require in camera review - i.e., by the judge in chambers rather than open court - and a judicial determination that further disclosure is required to assure a fair trial. (Pretty standard, stock-in-trade for federal district court judges, imho.) (Edit: note " in camera " is a Latin term and legal term of art, and does not refer to or mean actual cameras whatsoever.)

And, any permitted use of subject recordings must be subject to a Protective Order of confidentiality and maintained under seal to prevent use "for purposes other than the proceeding".

[ [i]The foregoing is not legal advice or counsel whatsoever and is not permitted to be construed or interpreted in any manner by any person or entity as legal advice or counsel - not least because there is no such thing as anonymously sourced legal advice or counsel in the United States (or any other such place as may comprehend the written English word)..... and for all the other reasons the sophisticated and good-spirited PPRuNe community will already have realized. . . . hopefully with the proper and expected smirk. ]

Now, editorially: I argue emphatically that free dissemination of recordings would be very, very unfortunate because it would produce - and I'm not trying to exaggerate - disastrous effects. The prior posters have articulated the reasons this would occur, and I won't repeat, mostly to avoid short-changing any of the previously - and convincingly and validly - stated points.

I do, however, disagree pretty strongly with the assertion that such unfortunate bad results already are occuring despite non-disclosure rules. First, although advocates, activists and would-be experts can run with partial information and fill in the blanks freely, everyone under the Sun knows that such persons have agendas. Maybe they're lawyers and maybe they're flaks or lobbyists - it isn't important what hat they wear, everyone knows they have an agenda. And so the goal or purpose of their attempts to fill in the omitted information is readily dismissed by anyone taking 15 seconds to give the matter some thought. And for those who can't or don't want to work, I mean can't or don't want to think for 15 seconds, well, the impact upon them of the agenda-driven information matters to the public interest about as much as whether any one of such individuals who can't or won't be bothered to think happens to like strawberries.

Second, is not the point about releasing the entire recording based upon being able to hear the nuance, the inflection, maybe the "transmission" of raw, and in what we're talking about, profound human emotion? (I actually anticipate hearing such CVR recordings could be quite traumatic for John or Jayne Q. Public, but not to digress.) And without that raw, unfiltered content, how much impact does the agenda-driven interpolated information have, in comparison? I suggest, it does not have nearly the same type of impact at all, and it very definitely does not have the same level, the same (if you will) quantity of impact, even if it is similar in nature to some degree. It would be pretty quickly shrugged off or forgotten ..... unlike the real recording were it to be heard.

In other words, the argument that bad things already are happening when omitted information is supplied in the public domain is wrong, first, because "consider the source" - everyone knows the agenda-driven information is for that purpose (and usually financial, at least insofar as trial and defense counsel are concerned), and second, the made-up or interpolated information lacks significant impact in and of itself, in comparison.

If this SLF/attorney had anything to say about changing these legal and policy rules, . . . . . . . well, I don't, so.
(I would have posted sooner but I made the mistake of trying to read the thread's progess since last night first.... with probably 12 pages now still to go, I hope this post hasn't been entirely superfluous or otherwise obnoxious.)
_______________________________________________________

Two separate fuel switches set to cut off, at one of the most critical phases of flight where doing so would lead to an unrecoverable situation, followed by one pilot asking the other why he set the switches to cut off.

No AD from Boeing or NTSB.

Come on.

Given that there's no evidence that the Fuel Cut-off Switches, or indeed any other part of the aircraft functioned incorrectly, what exactly should such an Airworthiness Directive be saying?

Can you articulate a specific reason or grounds for thinking a camera on the flight deck can reduce the number of pilot suicides? Or is your aim merely to reduce the number of arguments about them?

It seems like a "but the children!" argument, an appeal to emotion. Same with the appeal to MH370 upthread, a camera in the cockpit would have done nothing as satellite communications were off, and the flight recorders are at the bottom of the ocean.

Camera footage from the helicopter would've helped understand what went wrong in the DCA mid-air, but that was a military craft, so...

I had a "page 1 of google results" deep look into rail, knowing that the cab cameras have helped the NTSB before, but then the external camera tends to show more interesting stuff for trains than for aircraft. In rail, camera introduction was piecewise and unregulated, often by companies who wanted to be seen doing something after an accident, and regulation came afterwards (freight trains are still not regulated).

https://www.law.cornell.edu/cfr/text/49/229.136 If I were to regulate cameras in the cockpit, I'd first try it on a smaller scale, to see if there are unforseen negative effects on safety. I'd answer the question, do pilots behave differently when there are cameras? and if so, is the change for better or worse?

Do training simulators have cameras, and is the footage used to debrief simulator sessions?

Former Boeing Engineer who was in the room for some 787 AD discussions.... What exactly would you expect Boeing to put in the AD? "Don't put the fuel switches to cutoff unless you really mean to"? Let alone ADs are not in anyway a method for pilot training or actions, they are for the airline engineering and maintenance teams. What would you think Boeing should ask airlines to do in this proposed AD?

I'm sure the current team has already done the systems analysis to see if there was any possible way these weren't completely isolated systems (which I'm pretty confident they are). Let alone the initial report categorically says at this point there are no design issues found with Boeing or GE.

I have been hesitating to ask, but I'd like to check whether something I spotted is significant. (I think it is probably NOT significant, but it does no harm to confirm this whilst there is little in the way of new information to discuss).

I believe all three sources are reliable and verified.

1. Aviation Daily, June 25: "the DGCA carried out surveillance... at major airports, including those in Delhi and Mumbai. The surveillance order was issued on June 19, and the DGCA summarized its findings in a June 24 statement.

\x93The assessment covered a wide range of areas such as flight operations, airworthiness, ramp safety, air traffic control, pre-flight medical evaluations and communication, navigation and surveillance systems."

The order was issued on June 19, a week after AI171, and could feasibly have been informed by initial findings from the investigation (though not from anything on the EAFRs, which were not downloaded until much later). However, the timeframe is so tight that I'm inclined to think the assessment was either (a) a complete coincidence, or (b) a reassurance exercise.

Question : is it standard to include a review of pre-flight medical evaluations in such an exercise? (I don't see why it wouldn't be).

2. PIB press release from the Ministry of Civil Aviation on 26 JUN 2025 1:17PM: "The [investigation] team, constituted as per international protocol, is led by DG AAIB, and includes an aviation medicine specialist , an ATC officer, and representatives from NTSB."

The very first team member mentioned is an aviation medicine specialist. This could be coincidence or due to any number of trivial reasons, e.g. alphabetical order by surname. Still, I remember raising an eyebrow at the time (several weeks ago, to be clear).

The Preliminary Report ( PR ) includes a much longer list of team members on page 5, whereas the aforementioned press release singles out three in particular. Relevant?

3. The PR implies that the Aviation Medicine Specialist and an Aviation Psychologist were both drafted in as supplementary Subject Matter Experts (alongside several others I should add) at some point after the original team had been established.

I expect this is a common occurrence, but is it universal ? Question: At what stage of an investigation would one typically pick up the phone to these particular SMEs (automatically on day one or as deemed necessary)?

Individually, the above observations seem mostly routine to me. Together, they strike me as little more than a coincidence, but still... Do those with experience of such investigations have a view on the drafting-in, and the disclosure, of these two SMEs within the first two weeks of an investigation?

Disclaimer: By setting out my sources and thought process in some detail, it may create the impression that I am pushing an agenda. I assure you I am not. I am merely trying to be unambiguous about the facts I am asking you to opine on.

Not actually how it works.

The NTSB, Boeing, GE and AAIB-UK personnel involved in the team are 'advisory', along with various SMEs. They don't get to 'negotiate' and I seriously doubt that they'd be given any chance to. They would have examined the evidence, and reported what they found and what conclusions could be drawn from it.

The report is written the way it is because it can at this stage only deal with pertinent facts as they are known, while the investigation continues in the expectation of unearthing more details.

As I have said before, the people who do this work are professionals, not there to play politics or represent business interests.

1982 JAL350, confirmed
1994 RAM630, confirmed
1997 SilkAir 185, NTSB says confirmed, Indonesian NTSC says undetermined, private investigation blames a technical fault
1999 EgyptAir 990, confirmed
2013 LAM470, confirmed
2014 MAH370, no report, no evidence
2015 Germanwings 9525, confirmed
2022 China Eastern 5735, media reports of pilot suicide strongly rejected by investigating agency, no report.

Excluding the last one because the investigating agency explicitly called reports of pilot suicide false we have 7 cases since the beginning of commercial aviation. 2+1 suspected cases since 2000. That's 1:300.000.000 to 1:200.000.000. Actually I erroneously included the last one in my previous posts. I don't think including a case where the investigating agency explicitly refuted claims of suicide is valid.

For those of you who wish to engage on the details of the China Eastern crash, and what is (or isn't) in the report, the thread is here.