June 17, 2025, 23:03:00 GMT
permalink Post: 11904743
BR, D Bru
June 18, 2025, 09:27:00 GMT
permalink Post: 11905057
I am becoming somewhat suspicious about the supply of some of the info on this event. Firstly, the data recorders have been in the hands of the authorities for many days now and must surely have revealed something significant, either good data on the initial cause or, perhaps, in the case of a major electrical failure, nothing much. Either way we've heard nothing.
Equally despite the even longer timescale casualties remain at a quoted 270 odd which seems to me likely highly inconsistent with the location of the accident. Only 30ish casualties on the ground? Is this likely, given the number of burned-out buildings we've seen (and I get the impression we've also not been shown the true extent of the devastation.)
My impression is that the authorities know much more than they are saying and are witholding it which suggests to me that there are aspects of 'saving face' perhaps in a reluctance to admit what happened, which implies the truth - of both initial cause and casualty numbers - may be uncomfortable politically.
June 18, 2025, 12:06:00 GMT
permalink Post: 11905184
I wonder if the delay in announcing any preliminary findings is because of the enormity of the consequences.
Let us say the investigation team have discovered a unique technical fault that caused the accident, but don\x92t yet know why it happened, how would the team proceed? On the one hand they\x92ve uncovered a fault which could reoccur and cause another accident (but a fault that has only happened once in 14 years). On the other hand a grounding would have enormous commercial consequences worldwide, with the possibility that an inspection and/or rectification are not yet available.
What would they do?
Let us say the investigation team have discovered a unique technical fault that caused the accident, but don\x92t yet know why it happened, how would the team proceed? On the one hand they\x92ve uncovered a fault which could reoccur and cause another accident (but a fault that has only happened once in 14 years). On the other hand a grounding would have enormous commercial consequences worldwide, with the possibility that an inspection and/or rectification are not yet available.
What would they do?
June 18, 2025, 13:46:00 GMT
permalink Post: 11905266
June 19, 2025, 03:05:00 GMT
permalink Post: 11905688
The seat back story
@ferry pilot and others who mentioned the seat back collapsing: That was from an entirely unrelated incident on Air India Express flight 611 in 2018 which got poorly rehashed / fakenewsed into a bogus theory over the last week. It was a 737. It did *not* happen on AI171.
For what it's worth, the AIX 611 story in 2018 involved a 737 captain's seat back being overtightened and suddenly collapsing backwards during the takeoff roll. He had been guarding the thrust levers and reflexively grabbed them when falling back, causing a thrust reduction from 98% N1 to 75% N1 or thereabouts. Control was immediately transferred to the other pilot but the inadvertent thrust change was not corrected immediately, and the plane took off a few seconds later with a tail strike, scraping the runway, flying through the localizer and demolishing part of the airport perimeter wall with its landing gear. During the climb, the flight crew ran several system checks and landing gear tests to reassure themselves the plane was fine, then proceeded with the flight, pressurizing the aircraft and whatnot. They evidently did not consult the tail strike procedure. Many hours later they were ordered by company to divert and land quickly after the damage was seen at the airport. After landing, the plane was found to have a fair bit of damage, including part of the perimeter wall's barbed wire fencing material wrapped around the landing gear. But zero injuries, and the plane was fixed and flew again.
It's an entertaining story because of the cause and the happy ending, but had nothing to do with AI171, for which we all await the preliminary report.
For what it's worth, the AIX 611 story in 2018 involved a 737 captain's seat back being overtightened and suddenly collapsing backwards during the takeoff roll. He had been guarding the thrust levers and reflexively grabbed them when falling back, causing a thrust reduction from 98% N1 to 75% N1 or thereabouts. Control was immediately transferred to the other pilot but the inadvertent thrust change was not corrected immediately, and the plane took off a few seconds later with a tail strike, scraping the runway, flying through the localizer and demolishing part of the airport perimeter wall with its landing gear. During the climb, the flight crew ran several system checks and landing gear tests to reassure themselves the plane was fine, then proceeded with the flight, pressurizing the aircraft and whatnot. They evidently did not consult the tail strike procedure. Many hours later they were ordered by company to divert and land quickly after the damage was seen at the airport. After landing, the plane was found to have a fair bit of damage, including part of the perimeter wall's barbed wire fencing material wrapped around the landing gear. But zero injuries, and the plane was fixed and flew again.
It's an entertaining story because of the cause and the happy ending, but had nothing to do with AI171, for which we all await the preliminary report.
June 19, 2025, 14:51:00 GMT
permalink Post: 11906087
OK, I promised some
informed speculation
when I got back, so here goes:
Disclaimer: never worked the 787, so my detailed knowledge is a bit lacking.
First off, this is perplexing - especially if the RAT was deployed. There is no 'simple' explanation that I can come up with.
GEnx-1B engines have been exceptionally reliable, and the GE carbon composite fan blades are very robust and resistant to bird strike damage (about 15 years after the GE90 entry into service, I remember a GE boast that no GE90 (carbon composite) fan blades had needed to be scrapped due to damage (birdstrike, FOD, etc. - now that was roughly another 15 years ago, so is probably no longer true, but it shows just how robust the carbon composite blades are - far better than the more conventional titanium fan blades).
Not saying it wasn't somehow birdstrike related, just that is very unlikely (then again, all the other explanations I can come up with are also very unlikely
).
Using improper temp when calculating TO performance - after some near misses, Boeing added logic that cross-compares multiple total temp probes - aircraft TAT (I think the 787 uses a single, dual element probe for aircraft TAT, but stand to be corrected) and the temp measured by the engine inlet probes - and puts up a message if they disagree by more than a few degree tolerance - so very, very unlikely.
N1 power setting is somewhat less prone to measurement and power setting errors than EPR (N1 is a much simpler measurement than Rolls EPR) - although even with EPR, problems on both engines at the same time is almost unheard of.
The Auto Thrust (autothrottle) function 'falls asleep' at 60 knots - and doesn't unlock until one of several things happens - 250 knots, a set altitude AGL is exceeded (I'm thinking 3,000 ft. but the memory is fuzzy), thrust levers are moved more than a couple of degrees, or the mode select is changed (memory says that last one is inhibited below 400 ft. AGL). So an Auto Thrust malfunction is also extremely unlikely. Further, a premature thrust lever retard would not explain a RAT deployment.
TO does seem to be very late in the takeoff role - even with a big derate, you still must accelerate fast enough to reach V1 with enough runway to stop - so there is still considerable margin if both engines are operating normally. That makes me wonder if they had the correct TO power setting - but I'm at a loss to explain how they could have fouled that up with all the protections that the 787 puts on that.
If one engine did fail after V1, it's conceivable that they shut down the wrong engine - but since this happened literally seconds after takeoff, it begs the question why they would be in a big hurry to shut down the engine. Short of an engine fire, there is nothing about an engine failure that requires quick action to shut it down - no evidence of an engine fire, and even with an engine fire, you normally have minutes to take action - not seconds.
The one thing I keep thinking about is someone placing both fuel switches to cutoff immediately after TO. Yes, it's happened before (twice - 767s in the early 1980s), but the root causes of that mistake are understood and have been corrected. Hard to explain how it could happen ( unless, God forbid, it was intentional ).
Disclaimer: never worked the 787, so my detailed knowledge is a bit lacking.
First off, this is perplexing - especially if the RAT was deployed. There is no 'simple' explanation that I can come up with.
GEnx-1B engines have been exceptionally reliable, and the GE carbon composite fan blades are very robust and resistant to bird strike damage (about 15 years after the GE90 entry into service, I remember a GE boast that no GE90 (carbon composite) fan blades had needed to be scrapped due to damage (birdstrike, FOD, etc. - now that was roughly another 15 years ago, so is probably no longer true, but it shows just how robust the carbon composite blades are - far better than the more conventional titanium fan blades).
Not saying it wasn't somehow birdstrike related, just that is very unlikely (then again, all the other explanations I can come up with are also very unlikely
).
Using improper temp when calculating TO performance - after some near misses, Boeing added logic that cross-compares multiple total temp probes - aircraft TAT (I think the 787 uses a single, dual element probe for aircraft TAT, but stand to be corrected) and the temp measured by the engine inlet probes - and puts up a message if they disagree by more than a few degree tolerance - so very, very unlikely.
N1 power setting is somewhat less prone to measurement and power setting errors than EPR (N1 is a much simpler measurement than Rolls EPR) - although even with EPR, problems on both engines at the same time is almost unheard of.
The Auto Thrust (autothrottle) function 'falls asleep' at 60 knots - and doesn't unlock until one of several things happens - 250 knots, a set altitude AGL is exceeded (I'm thinking 3,000 ft. but the memory is fuzzy), thrust levers are moved more than a couple of degrees, or the mode select is changed (memory says that last one is inhibited below 400 ft. AGL). So an Auto Thrust malfunction is also extremely unlikely. Further, a premature thrust lever retard would not explain a RAT deployment.
TO does seem to be very late in the takeoff role - even with a big derate, you still must accelerate fast enough to reach V1 with enough runway to stop - so there is still considerable margin if both engines are operating normally. That makes me wonder if they had the correct TO power setting - but I'm at a loss to explain how they could have fouled that up with all the protections that the 787 puts on that.
If one engine did fail after V1, it's conceivable that they shut down the wrong engine - but since this happened literally seconds after takeoff, it begs the question why they would be in a big hurry to shut down the engine. Short of an engine fire, there is nothing about an engine failure that requires quick action to shut it down - no evidence of an engine fire, and even with an engine fire, you normally have minutes to take action - not seconds.
The one thing I keep thinking about is someone placing both fuel switches to cutoff immediately after TO. Yes, it's happened before (twice - 767s in the early 1980s), but the root causes of that mistake are understood and have been corrected. Hard to explain how it could happen ( unless, God forbid, it was intentional ).
June 20, 2025, 04:31:00 GMT
permalink Post: 11906581
The state is not yet required to report more than the preliminary report IAW Annex 13, however, the observations that are readily available to the investigators and the OEM teams will not be conducive to good nights sleep by any of them.
The regulator is not in a position to make an EAD or other airworthiness directive without a justifiable basis, and the very fact this is suggestive of a failure mode that is catastrophic, even though obviously low probability doesn't permit the risk to be accepted. With the system architecture on the B787, if viewed as a Bayesian assessment, the highest probability remains an environmental item outside of the design as approved. The problem with that area as we have seen before, it is very difficult to prove events with icing (Roselawn etc) or moisture ingress in most cases, it will likely require a forensic teardown of the control systems of the engine to determine what damage may have occurred before impact. That is a daunting proposition when the area involved has been at the center of the impact and post impact fire. I have more confidence in the systems engineers and software than the ability to maintain an environment that does not cause adverse outcomes.
June 20, 2025, 14:21:00 GMT
permalink Post: 11907014
Background info from "The Hindu",
Ahmedabad plane crash: Aircraft Accident Investigation Bureau yet to decide where black box data will be decoded
Black Boxes
Preliminary Report
Black Boxes
The government body investigating the Air India Boeing 787-8 crash in Ahmedabad last week will take a decision on where the black box data will be decoded \x93after due assessment of all technical, safety, and security considerations,\x94 the Ministry of Civil Aviation said on Thursday (June 19, 2025).
The statement said two different sets of black boxes were recovered from the crash site, one on June 13 and another on June 16. Each black box unit comprises the Digital Flight Data Recorder (DFDR) and Cockpit Voice Recorder (CVR).
The statement said two different sets of black boxes were recovered from the crash site, one on June 13 and another on June 16. Each black box unit comprises the Digital Flight Data Recorder (DFDR) and Cockpit Voice Recorder (CVR).
A government official closely involved with the probe said there would be a preliminary report. Interestingly, during the only other airline crash investigated by the AAIB (which was formed in 2012), after the Mangalore crash of May 2010 \x97 i.e. Calicut accident \x97 only the final report was published within a year.
Officials, past and present, explained that the rules under which the AAIB carries out an investigation do not specify a timeline for a preliminary report, even though the UN aviation safety watchdog, the International Civil Aviation Organisation\x92s Annex 13 requires one within 30 days. A similar rule is not part of the Aircraft (Investigation of Accidents and Incidents) Rules, 2017 formed under the principal law, the Bharatiya Vayuyan Vidheyak, 2024.
(...)
One of the above mentioned officials said the Calicut probe team didn\x92t release a preliminary report because the Rules don\x92t lay down a timeline for it and require such a report to only categorise the nature of the mishap. He added that the team involved in the drafting of the Rules held the opinion that such a report could be vastly different from the final investigation report, which may result in public criticism and media backlash.
Officials, past and present, explained that the rules under which the AAIB carries out an investigation do not specify a timeline for a preliminary report, even though the UN aviation safety watchdog, the International Civil Aviation Organisation\x92s Annex 13 requires one within 30 days. A similar rule is not part of the Aircraft (Investigation of Accidents and Incidents) Rules, 2017 formed under the principal law, the Bharatiya Vayuyan Vidheyak, 2024.
(...)
One of the above mentioned officials said the Calicut probe team didn\x92t release a preliminary report because the Rules don\x92t lay down a timeline for it and require such a report to only categorise the nature of the mishap. He added that the team involved in the drafting of the Rules held the opinion that such a report could be vastly different from the final investigation report, which may result in public criticism and media backlash.
June 20, 2025, 21:17:00 GMT
permalink Post: 11907329
As has been gone over before, the auththrottles normally stay in HOLD until 400 AGL at which point they engage in THR REF xxx VNAV SPD to whatever value was programmed in the RTOW.
BUT
Say the MCP is mis-set to 200\x92 or so. VNAV never engages and the expected mode (from others; I`ve never tried it) would be SPD xxx ALT.
The modes still engage regardless of whether or not the airplane is on autopilot; the autopilot itself just follows the flight director commands (and the PF certainly woudn`t follow the FD in this case). Autothrottles are independent of autopilot.
BUT
Say the MCP is mis-set to 200\x92 or so. VNAV never engages and the expected mode (from others; I`ve never tried it) would be SPD xxx ALT.
The modes still engage regardless of whether or not the airplane is on autopilot; the autopilot itself just follows the flight director commands (and the PF certainly woudn`t follow the FD in this case). Autothrottles are independent of autopilot.
I am actually looking for an answer from a pilot (or at least someone with an FCOM who can share any relevant passages) because nothing I have been able to look up on my own suggests that this is the case. All secondary sources I can find just say that the autothrottle is inhibited under 400 feet on takeoff, with my impression being that the crew is expected to manage thrust manually during that phase of flight. The incidents I was able to turn up involving an aircraft attempting to capture a target altitude at takeoff specifically don't help either:
- G-ECOE: Flight was completely normal until the crew engaged the autopilot at 1350 feet, at which point the aircraft started diving to the target of 0 feet. However it involved a Dash 8 and not only is that not a Boeing aircraft, it doesn't have an autothrottle to begin with. Nothing to conclude from this.
- F-WWKH: Again automated deviation was triggered by the crew engaging the autopilot a few seconds after takeoff as part of a test flight. However again also not a Boeing aircraft (an A330) and the selected target altitude was 2000 feet so the autopilot tried to pitch up to capture it. Not sure if anything can be concluded from this.
- A6-EQI: The most relevant, being a Boeing 777, with wide speculation being that the selected altitude was left at 0 feet. However the preliminary report is very thin so there's little to go on in the way of factual information, but the problem seems to entirely have been that the pilot flying was following the flight directors without question. There's zero indication of any loss of thrust, in fact they seem to have nearly entered an overspeed condition partly due to the shallow climb angle implying that the engines were doing just fine. So it doesn't seem like the selected altitude caused the autothrottle to do anything.
I am sorry if it seems like I'm banging on about this autothrottle point a bit much but as an engineer it just seems completely backwards to me. What exactly is the point of the HOLD mode or of setting those specific gates (80 knots, 400 feet) if the autothrottle can so easily come out of it? The design might as well not have it at all and just leave the autothrottle in THR REF for takeoff then - what would be the difference?
June 20, 2025, 21:52:00 GMT
permalink Post: 11907348
To be clear, are you stating categorically or guessing (or neither, and I'm misreading you and you mean something else) that the 787's autothrottle will come
out of HOLD
and into SPD mode
below 400 feet
by design in response to the altitude that's set in the mode control panel, entirely by itself, without the autopilot engaged? Not that this is the way it would behave in normal flight - that this is the way it is
designed
to behave while it's in HOLD mode for takeoff?
I am actually looking for an answer from a pilot (or at least someone with an FCOM who can share any relevant passages) because nothing I have been able to look up on my own suggests that this is the case. All secondary sources I can find just say that the autothrottle is inhibited under 400 feet on takeoff, with my impression being that the crew is expected to manage thrust manually during that phase of flight. The incidents I was able to turn up involving an aircraft attempting to capture a target altitude at takeoff specifically don't help either:
- G-ECOE: Flight was completely normal until the crew engaged the autopilot at 1350 feet, at which point the aircraft started diving to the target of 0 feet. However it involved a Dash 8 and not only is that not a Boeing aircraft, it doesn't have an autothrottle to begin with. Nothing to conclude from this.
- F-WWKH: Again automated deviation was triggered by the crew engaging the autopilot a few seconds after takeoff as part of a test flight. However again also not a Boeing aircraft (an A330) and the selected target altitude was 2000 feet so the autopilot tried to pitch up to capture it. Not sure if anything can be concluded from this.
- A6-EQI: The most relevant, being a Boeing 777, with wide speculation being that the selected altitude was left at 0 feet. However the preliminary report is very thin so there's little to go on in the way of factual information, but the problem seems to entirely have been that the pilot flying was following the flight directors without question. There's zero indication of any loss of thrust, in fact they seem to have nearly entered an overspeed condition partly due to the shallow climb angle implying that the engines were doing just fine. So it doesn't seem like the selected altitude caused the autothrottle to do anything.
I am sorry if it seems like I'm banging on about this autothrottle point a bit much but as an engineer it just seems completely backwards to me. What exactly is the point of the HOLD mode or of setting those specific gates (80 knots, 400 feet) if the autothrottle can so easily come out of it? The design might as well not have it at all and just leave the autothrottle in THR REF for takeoff then - what would be the difference?
I am actually looking for an answer from a pilot (or at least someone with an FCOM who can share any relevant passages) because nothing I have been able to look up on my own suggests that this is the case. All secondary sources I can find just say that the autothrottle is inhibited under 400 feet on takeoff, with my impression being that the crew is expected to manage thrust manually during that phase of flight. The incidents I was able to turn up involving an aircraft attempting to capture a target altitude at takeoff specifically don't help either:
- G-ECOE: Flight was completely normal until the crew engaged the autopilot at 1350 feet, at which point the aircraft started diving to the target of 0 feet. However it involved a Dash 8 and not only is that not a Boeing aircraft, it doesn't have an autothrottle to begin with. Nothing to conclude from this.
- F-WWKH: Again automated deviation was triggered by the crew engaging the autopilot a few seconds after takeoff as part of a test flight. However again also not a Boeing aircraft (an A330) and the selected target altitude was 2000 feet so the autopilot tried to pitch up to capture it. Not sure if anything can be concluded from this.
- A6-EQI: The most relevant, being a Boeing 777, with wide speculation being that the selected altitude was left at 0 feet. However the preliminary report is very thin so there's little to go on in the way of factual information, but the problem seems to entirely have been that the pilot flying was following the flight directors without question. There's zero indication of any loss of thrust, in fact they seem to have nearly entered an overspeed condition partly due to the shallow climb angle implying that the engines were doing just fine. So it doesn't seem like the selected altitude caused the autothrottle to do anything.
I am sorry if it seems like I'm banging on about this autothrottle point a bit much but as an engineer it just seems completely backwards to me. What exactly is the point of the HOLD mode or of setting those specific gates (80 knots, 400 feet) if the autothrottle can so easily come out of it? The design might as well not have it at all and just leave the autothrottle in THR REF for takeoff then - what would be the difference?
I am guessing because although I flew the 777 I never tried a low altitude capture before VNAV engaged — and it`s been a few years). But think it probably would. As one goes through 50’ LNAV engages; VNAV is normally armed prior to the EFIS check if it`s to be used (which it usually is). So in this scenario LNAV would have been engaged but since VNAV is armed but never engages my guess is that the automatics would engage in SPD/LVAV/ALT. I could be wrong. The PF would have been hand flying (and obviously not following the flight director with autothrottles engaged).
HOLD is present in many other regimes of flight; all it means is that the auththrottle (right now) is not controlling the throttles and they stay where they are—and the PF can move them if desired at will. Fr` instance, when descending in FLCH or even VNAV SPD the throttles will usually be in HOLD. (To me this usually meant `hold` the throttles—and tweek them in descent as required). Thrust can be modulated to adjust rate of descent (the throttles become vertical speed levers). On altitude capture in the case of FLCH or path capture in the case of VNAV SPD (in descent) the auththrottles kick in and it becomes SPD/xxx/ALT (or VPTH or VALT as the case might be).
Most everyone knew the autothrottles would not engage below 400` and that FLCH in descent at very low altitudes was not an appropriate mode — and they did not activate providing low speed protection in the case of Asiana.
IIRC our throttles went into HOLD at 60 knots and stayed there until VNAV activated (THR REF—takeoff thrust). It was also possible that the autothrottles under some environmentals wouldn`t fully achieve takeoff thrust setting (EPR or N1 depending on which engines) and they could be manually moved in HOLD to achieve it. Although I don`t remember that as ever happening.
But at this point it`s a guess because I never did it (MCP set at low altitude on takeoff with VNAV never engaging). Perhaps someone else has.
Last edited by Shep69; 20th June 2025 at 22:05 .
June 21, 2025, 04:58:00 GMT
permalink Post: 11907483
I can guarantee you that the investigation is way ahead of this thread as they won't be stuck on a hamster wheel of irrelevant theories. The investigators are under no obligation to keep the general public informed minute by minute of where the investigation is. They are obliged under annex 13 to release a preliminary report in 30 days of the accident then its every 6 months, if there is anything to report. Anything that is important to release to the engine and airframe manufacturers will be done as a separate part of the process. Having been involved in the investigation process I can tell you from first hand experience that pet theories, as expounded on these pages, are like trying to cure cancer with just a petrie dish.
June 22, 2025, 07:24:00 GMT
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.
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.)
June 29, 2025, 15:55:00 GMT
permalink Post: 11913101
.....stating that a report into this crash is expected within three months.
June 29, 2025, 19:00:00 GMT
permalink Post: 11913178
A jet upset is an undesirable aircraft state...ie stall, or severe turbulence causing the aircraft to flip upside down dive etc... Looking at the Air India incident, the aircraft was not in any of those situations... In fact, if you weren't aware, you would think it was landing. This is something else entirely.
That said, your pedantry from a different angle is accepted.
Back from early flying, when you were first trying it out, your instructor taught you that Power plus attitude equals performance. (While true enough, power plus attitude plus configuration is a more accurate formulation).
That reply to you offered, yes, your response is well put.
(Maybe it's my rotary wing experience that puts "power" into what controls flight, but no matter, we are discussing a 787-8).
Glad to hear that the Indian Government has a timeline for a prelim report. If it takes them a bit more time than ICAO wants, with alerts or bulletins issued as various things are confirmed, that probably serves the larger interest.
Mohol also stated that "sabotage" has not yet been ruled out at this stage of the investigation.
Spoiler
June 30, 2025, 13:05:00 GMT
permalink Post: 11913609
India's Minister of State for Civil Aviation appears to be confirming in this
this interview
that the cause of the accident was a dual engine failure. Which is, I think, the first vaguely official confirmation of what happened that has been released? He also confirmed that all the data from the recorders has been downloaded and is being processed by the Indian AAIB, no boxes have been sent abroad.
The 30 day deadline for the preliminary report is July 12th.
The 30 day deadline for the preliminary report is July 12th.
June 30, 2025, 13:08:00 GMT
permalink Post: 11913613
We know that the right-hand GEnx-1B was removed for overhaul and re-installed in March 2025 so it was at “zero time” and zero cycles, meaning a performance asymmetry that the FADEC would have to manage every time maximum thrust is selected. If the old engine was still on the pre-2021 EEC build while the fresh engine carried the post-Service Bulletin software/hardware, a dual “commanded rollback” is plausible.
A latent fault on one channel with the mid-life core can prompt the other engine to match thrust to maintain symmetry, leading to dual rollback.
A latent fault on one channel with the mid-life core can prompt the other engine to match thrust to maintain symmetry, leading to dual rollback.
Originally Posted by
silverelise
He also confirmed that all the data from the recorders has been downloaded and is being processed by the Indian AAIB,
no boxes have been sent abroad.
The 30 day deadline for the preliminary report is July 12th.
The 30 day deadline for the preliminary report is July 12th.
Originally Posted by
the linked article
Investigators still haven’t ruled out the possibility of sabotage being behind the Air India crash in
Ahmedabad
earlier this month that
killed 274 people
, according to India’s aviation minister. The Aircraft Accident Investigation Bureau (AAIB) has confirmed that the aircraft’s flight recorders – known as black boxes – will not be sent outside the country for assessment and will be analysed by the agency, said Murlidhar Mohol, the minister of state for civil aviation.l
June 30, 2025, 15:49:00 GMT
permalink Post: 11913716
India's Minister of State for Civil Aviation appears to be confirming in this interview that the cause of the accident was a dual engine failure. Which is, I think, the first vaguely official confirmation of what happened that has been released? He also confirmed that all the data from the recorders has been downloaded and is being processed by the Indian AAIB, no boxes have been sent abroad.
The 30 day deadline for the preliminary report is July 12th.
The 30 day deadline for the preliminary report is July 12th.
The minister called the crash a \x93rare case\x94 and, referring to claims by veteran pilots and experts that a dual-engine failure may have led to the crash, said: \x93It has never happened that both engines have shut down together.\x94 \x93Once the report comes, we will be able to ascertain if it was an engine problem or fuel supply issue or why both engines had stopped functioning.
July 01, 2025, 12:24:00 GMT
permalink Post: 11914237
Air India Crash Preliminary Report Next Week, Will Outline Possible Causes
from NDTV
New Delhi: The preliminary probe report on the Air India crash, in which at least 270 people were killed - including 241 on board the flight - is expected to be released by July 11. The document, which is likely to be four to five pages long, will be crucial because it will provide initial insights into the crash, including the possible causes.
Sources said the report will include details about the aircraft, which was a Boeing Dreamliner 787-8, the crew, conditions at the Ahmedabad airport, and the weather on June 12, when Air India flight 171 crashed, roughly 30 seconds after taking off.
Details about the wreckage will also be part of the report, as will the name of the investigator in charge. The document will chart the progress of the probe, outline the next steps that need to be taken and highlight areas that need further investigation.
As per International Civil Aviation Organization (ICAO) guidelines, India is required to file a preliminary report within 30 days of the crash.
New Delhi: The preliminary probe report on the Air India crash, in which at least 270 people were killed - including 241 on board the flight - is expected to be released by July 11. The document, which is likely to be four to five pages long, will be crucial because it will provide initial insights into the crash, including the possible causes.
Sources said the report will include details about the aircraft, which was a Boeing Dreamliner 787-8, the crew, conditions at the Ahmedabad airport, and the weather on June 12, when Air India flight 171 crashed, roughly 30 seconds after taking off.
Details about the wreckage will also be part of the report, as will the name of the investigator in charge. The document will chart the progress of the probe, outline the next steps that need to be taken and highlight areas that need further investigation.
As per International Civil Aviation Organization (ICAO) guidelines, India is required to file a preliminary report within 30 days of the crash.
July 09, 2025, 07:04:00 GMT
permalink Post: 11918167
Air India jet's fuel switches in focus, as crash preliminary report nears
From
Reuters
Summary
Summary
- Air India crash probe focuses on engine fuel control switches - source
- Preliminary report expected by Friday - sources
- Report could provide early details into world's worst aviation disaster in a decade
- Probe has been dogged by questions over lack of information
- India reversed course and now allowing UN specialist observer status - sources
July 8 (Reuters) - A preliminary report into the deadly crash of an Air India jetliner in June is expected to be released by Friday, three sources with knowledge of the matter said, with one adding the probe had narrowed its focus to the movement of the plane's fuel control switches.
The London-bound Boeing (BA.N) 787 Dreamliner, which started losing height after reaching an altitude of 650 feet, crashed moments after takeoff from Ahmedabad, India, killing 241 of the 242 people on board and the rest on the ground.
The investigation into the Air India crash is focusing on the movement of the engine fuel control switches following an analysis of the 787's flight and voice data recorders, along with a simulation by Boeing of the aircraft's final moments, one of the sources said.
The investigation has not raised any immediate concerns over mechanical failure, the source said, and there has been no bulletin to airlines recommending changes to 787 operations . Boeing declined to comment.
Aviation industry publication the Air Current first reported the focus on the fuel switches that help power the plane's two engines.
It was not clear what specific actions involving the fuel switches are being looked at by investigators. Sources told the Air Current that the available information on the black boxes could not rule in or out improper, inadvertent or intentional actions that preceded or followed the apparent loss of thrust before the aircraft crashed.
U.S. aviation safety expert John Cox said a pilot would not be able to accidentally move the fuel switches that feed the engines. "You can't bump them and they move," he said.
Cox added that if a switch was shut off, the effect would be almost immediate, cutting off engine power.
Most air crashes are caused by multiple factors. The investigation is focusing at least partly on engine thrust , Reuters reported last month.
While the report from Indian investigators could be made public on Friday, the three sources cautioned to Reuters that plans could change and there was no clarity on how much information would be available in the document, which comes about 30 days after the June 12 tragedy.
The sources spoke on condition of anonymity because they were not authorised to speak to media.
India's Aircraft Accident Investigation Bureau, which is leading the probe under international rules , did not respond immediately to a request for comment outside normal business hours.
However, India reversed course on an earlier decision reported by Reuters to prevent a U.N. aviation investigator from joining the probe, two senior sources said.
A specialist from the U.N.'s International Civil Aviation Organization (ICAO) was granted observer status, following an unusual request by the agency to offer its support.
ICAO declined to comment, adding in a statement that any public discussion of "cooperative arrangements," would require authorisation by the state.
The crash is challenging the Tata Group's ambitious campaign to restore Air India's reputation and revamp its fleet, after taking the carrier over from the government in 2022.
India is banking on a boom in aviation to support wider development goals, with New Delhi saying it wants India to be a job-creating global aviation hub along the lines of Dubai, which currently handles much of the country's international traffic.
A panel of Indian lawmakers will review safety in the country's civil aviation sector and has invited several industry and government officials to answer questions on Wednesday, with topics set to include the recent plane crash.
Reporting by Allison Lampert in Montreal and David Shepardson in Washington; Additional reporting by Dan Catchpole in Seattle and Kanjyik Ghosh in Bengaluru; Editing by Jamie Freed
The London-bound Boeing (BA.N) 787 Dreamliner, which started losing height after reaching an altitude of 650 feet, crashed moments after takeoff from Ahmedabad, India, killing 241 of the 242 people on board and the rest on the ground.
The investigation into the Air India crash is focusing on the movement of the engine fuel control switches following an analysis of the 787's flight and voice data recorders, along with a simulation by Boeing of the aircraft's final moments, one of the sources said.
The investigation has not raised any immediate concerns over mechanical failure, the source said, and there has been no bulletin to airlines recommending changes to 787 operations . Boeing declined to comment.
Aviation industry publication the Air Current first reported the focus on the fuel switches that help power the plane's two engines.
It was not clear what specific actions involving the fuel switches are being looked at by investigators. Sources told the Air Current that the available information on the black boxes could not rule in or out improper, inadvertent or intentional actions that preceded or followed the apparent loss of thrust before the aircraft crashed.
U.S. aviation safety expert John Cox said a pilot would not be able to accidentally move the fuel switches that feed the engines. "You can't bump them and they move," he said.
Cox added that if a switch was shut off, the effect would be almost immediate, cutting off engine power.
Most air crashes are caused by multiple factors. The investigation is focusing at least partly on engine thrust , Reuters reported last month.
While the report from Indian investigators could be made public on Friday, the three sources cautioned to Reuters that plans could change and there was no clarity on how much information would be available in the document, which comes about 30 days after the June 12 tragedy.
The sources spoke on condition of anonymity because they were not authorised to speak to media.
India's Aircraft Accident Investigation Bureau, which is leading the probe under international rules , did not respond immediately to a request for comment outside normal business hours.
INFORMATION RELEASE
The probe has been dogged by questions over lack of information, after investigators took about two weeks to download flight recorder data after the crash. The Indian government held only one press conference on the incident, and no questions were taken.However, India reversed course on an earlier decision reported by Reuters to prevent a U.N. aviation investigator from joining the probe, two senior sources said.
A specialist from the U.N.'s International Civil Aviation Organization (ICAO) was granted observer status, following an unusual request by the agency to offer its support.
ICAO declined to comment, adding in a statement that any public discussion of "cooperative arrangements," would require authorisation by the state.
The crash is challenging the Tata Group's ambitious campaign to restore Air India's reputation and revamp its fleet, after taking the carrier over from the government in 2022.
India is banking on a boom in aviation to support wider development goals, with New Delhi saying it wants India to be a job-creating global aviation hub along the lines of Dubai, which currently handles much of the country's international traffic.
A panel of Indian lawmakers will review safety in the country's civil aviation sector and has invited several industry and government officials to answer questions on Wednesday, with topics set to include the recent plane crash.
Reporting by Allison Lampert in Montreal and David Shepardson in Washington; Additional reporting by Dan Catchpole in Seattle and Kanjyik Ghosh in Bengaluru; Editing by Jamie Freed
July 09, 2025, 15:37:00 GMT
permalink Post: 11918467
I've seen a quote saying, "In accordance with international protocols, release of information on the air crash probe rests solely with the Indian authorities." This means that while there are other parties to the investigation, India's AAIB has the final say over what goes in these reports, in accordance with Annex 13. But ICAO would not say that India has the option not to release a report.