July 17, 2025, 00:47:00 GMT
permalink Post: 11924060
The switch is directly connected to the coils of a latching relay. That latching relay is directly connected to the coils of the spar valve. There is no digital logic device in the way,
The position of the switch is monitored (through a different set of contacts) by the EAFR (twice). The position of the spar valve is monitored by the EAFR.
Thus the recorder sees (twice) that the switch is moved, and that the valve moved in response.
Subjects
EAFR
Fuel (All)
Fuel Cutoff
Fuel Cutoff Switches
Spar Valves
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July 17, 2025, 01:16:00 GMT
permalink Post: 11924069
tdracer excellently summarised. But I'll confirm.
The switch is directly connected to the coils of a latching relay. That latching relay is directly connected to the coils of the spar valve. There is no digital logic device in the way,
The position of the switch is monitored (through a different set of contacts) by the EAFR (twice). The position of the spar valve is monitored by the EAFR.
Thus the recorder sees (twice) that the switch is moved, and that the valve moved in response.
The switch is directly connected to the coils of a latching relay. That latching relay is directly connected to the coils of the spar valve. There is no digital logic device in the way,
The position of the switch is monitored (through a different set of contacts) by the EAFR (twice). The position of the spar valve is monitored by the EAFR.
Thus the recorder sees (twice) that the switch is moved, and that the valve moved in response.
Subjects
EAFR
High Pressure Shutoff Valve
Spar Valves
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July 17, 2025, 07:57:00 GMT
permalink Post: 11924163
It's easy to go, "it must be suicide, there's nothing else in the preliminary report that explains it". Well, the things that might turn out to be a factor are not in the preliminary report because they're still being investigated. Fuel samples. The switches themselves, which suffered fire damage. A thorough understanding what can cause the transitions logged on the EAFR, and what did cause them.
YOU are one of the sources of "speculation of unknown origin".
Subjects
AAIB (All)
EAFR
Preliminary Report
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July 17, 2025, 12:40:00 GMT
permalink Post: 11924331
That's better than being at the mercy of speculation from the AAIB.
It's easy to go, "it must be suicide, there's nothing else in the preliminary report that explains it". Well, the things that might turn out to be a factor are not in the preliminary report because they're still being investigated. Fuel samples. The switches themselves, which suffered fire damage. A thorough understanding what can cause the transitions logged on the EAFR, and what did cause them.
YOU are one of the sources of "speculation of unknown origin".
It's easy to go, "it must be suicide, there's nothing else in the preliminary report that explains it". Well, the things that might turn out to be a factor are not in the preliminary report because they're still being investigated. Fuel samples. The switches themselves, which suffered fire damage. A thorough understanding what can cause the transitions logged on the EAFR, and what did cause them.
YOU are one of the sources of "speculation of unknown origin".
Subjects
AAIB (All)
EAFR
Fuel (All)
Fuel Cutoff Switches
Preliminary Report
RUN/CUTOFF
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July 17, 2025, 15:35:00 GMT
permalink Post: 11924443
Oldrightie
I am not aware of a part of the prelim report, second paragraph being discussed anywhere. Something I find, if I'm correct, not discussed yet for me surely very significant.
"The EGT was observed to be rising for both engines indicating relight. Engine 1\x92s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery . The EAFR recording stopped at 08:09:11"
Forgive my now 20 years into retirement as an F/O on the B737 400 and A320/21 but I still retain my lifelong avid interest in all things aviation. So am I correct in thinking this paragraph indicates significantly that eng2, right hand, core compressor had failed, albeit not explosively? It relit and fuel was being "re-introduced repeatedly "but could not arrest core speed deceleration". From day one I believed that no 2 failed after V1 and that the automatic correction for this on the 787 hid all but a possibly apparent small nose right on its climb out. Additionally I surmised that with all the warnings this produced, the low altitude and few seconds to address such a failure, the first recycle was offered up to the no 1 engine switch, in haste. The immediate result then RAT extension, a check on the engine parameters and an action on the no 2 switch, again in haste on realisation that was down on N2, then, sadly too late, No 1 recycled successfully. Unlike No 2. Heaven knows, a similar mistake was made on the Kegworth B737, when all he time in the world was available compared to AI171.
To me the long debate here about suicide is very unprofessional and surely this factual part of the report, has masses more credence, regardless of the consequences facing the AI crew.
If this bit about No 2 engine report is as I interpret, I would at least hope, if not already, someone else has picked it up, or at least it will get more attention ere long. God bless all the people so badly affected and I pray the cause will be one day revealed and not be buried to protect the money men. Has been known.
"The EGT was observed to be rising for both engines indicating relight. Engine 1\x92s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery . The EAFR recording stopped at 08:09:11"
Forgive my now 20 years into retirement as an F/O on the B737 400 and A320/21 but I still retain my lifelong avid interest in all things aviation. So am I correct in thinking this paragraph indicates significantly that eng2, right hand, core compressor had failed, albeit not explosively? It relit and fuel was being "re-introduced repeatedly "but could not arrest core speed deceleration". From day one I believed that no 2 failed after V1 and that the automatic correction for this on the 787 hid all but a possibly apparent small nose right on its climb out. Additionally I surmised that with all the warnings this produced, the low altitude and few seconds to address such a failure, the first recycle was offered up to the no 1 engine switch, in haste. The immediate result then RAT extension, a check on the engine parameters and an action on the no 2 switch, again in haste on realisation that was down on N2, then, sadly too late, No 1 recycled successfully. Unlike No 2. Heaven knows, a similar mistake was made on the Kegworth B737, when all he time in the world was available compared to AI171.
To me the long debate here about suicide is very unprofessional and surely this factual part of the report, has masses more credence, regardless of the consequences facing the AI crew.
If this bit about No 2 engine report is as I interpret, I would at least hope, if not already, someone else has picked it up, or at least it will get more attention ere long. God bless all the people so badly affected and I pray the cause will be one day revealed and not be buried to protect the money men. Has been known.
Subjects
AI171
EAFR
Parameters
Preliminary Report
RAT (All)
Relight
V1
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July 17, 2025, 17:57:00 GMT
permalink Post: 11924521
Non-intentional behaviours or impulsive action... that's a different matter. In that instance, the pilot is likely not to have given it any thought - as per your post from which I partially quoted just now.
Subjects
EAFR
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July 17, 2025, 18:46:00 GMT
permalink Post: 11924539
An interesting quotation from this: "She highlighted a similar incident during which one of the engines suddenly shut down midflight on an All Nippon Airways Boeing 787 during its final approach to Osaka, Japan, in 2019.
Investigators later found that the aircraft’s software had mistakenly interpreted the plane as being on the ground, triggering the thrust control malfunction accommodation system, which automatically moved the fuel switch from “run” to “cutoff” without any action from the pilots."
Is it also interesting that this incident occurred at the time of ground-to-air transition?
Investigators later found that the aircraft’s software had mistakenly interpreted the plane as being on the ground, triggering the thrust control malfunction accommodation system, which automatically moved the fuel switch from “run” to “cutoff” without any action from the pilots."
Is it also interesting that this incident occurred at the time of ground-to-air transition?
The TCMA shuts down one or more engines - but it doesn't move the switches to cut-off in any magical way. TCMA directly operates the fuel valves - but the switches stay on.
Of course there is no entry for the switches being operated on the EAFR when TCMA shuts down an engine!
Subjects
EAFR
Fuel (All)
Fuel Cutoff Switches
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July 17, 2025, 19:26:00 GMT
permalink Post: 11924560
Totally wrong.
The TCMA shuts down one or more engines - but it doesn't move the switches to cut-off in any magical way. TCMA directly operates the fuel valves - but the switches stay on.
Of course there is no entry for the switches being operated on the EAFR when TCMA shuts down an engine!
The TCMA shuts down one or more engines - but it doesn't move the switches to cut-off in any magical way. TCMA directly operates the fuel valves - but the switches stay on.
Of course there is no entry for the switches being operated on the EAFR when TCMA shuts down an engine!
Subjects
EAFR
Fuel (All)
Fuel Cutoff Switches
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July 17, 2025, 20:39:00 GMT
permalink Post: 11924609
Totally wrong.
The TCMA shuts down one or more engines - but it doesn't move the switches to cut-off in any magical way. TCMA directly operates the fuel valves - but the switches stay on.
Of course there is no entry for the switches being operated on the EAFR when TCMA shuts down an engine!
The TCMA shuts down one or more engines - but it doesn't move the switches to cut-off in any magical way. TCMA directly operates the fuel valves - but the switches stay on.
Of course there is no entry for the switches being operated on the EAFR when TCMA shuts down an engine!
Subjects
EAFR
EICAS
Fuel (All)
Fuel Cutoff
Fuel Cutoff Switches
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July 17, 2025, 21:08:00 GMT
permalink Post: 11924625
Eng1_TCMA_Shutdown_Local_EEC_A
Eng1_TCMA_Shutdown_Local_EEC_B
Eng2_TCMA_Shutdown_Local_EEC_A
Eng2_TCMA_Shutdown_Local_EEC_B
Subjects
EAFR
EICAS
Fuel (All)
Fuel Cutoff
Fuel Cutoff Switches
Parameters
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July 18, 2025, 00:02:00 GMT
permalink Post: 11924737
"There has been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB." - This will have been verified by the investigation team fairly rapidly. Verified reportable fact, included in the preliminary report.
Yes in the final report they would be in a position to make a statement like that. But in the preliminary - No.
Subjects
EAFR
Fuel (All)
Fuel Cutoff Switches
Preliminary Report
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July 18, 2025, 00:31:00 GMT
permalink Post: 11924760
Several posts (I think - Pls don't ask me to find and quote) - have made statements to the effect of "we'll never know which person moved the switches".
Question to our active flight crew.
The EAFR records column / yoke angle and input force . It will be easy to show who was controlling the aircraft at any moment. Do you think that if for example the FO, whilst actively flying the aircraft was the one to reset the switches back to run, in changing to a single hand on the yoke and turning to the switches, there would be any detectable change in input force / angle ? Or would that detail be lost in the noise?
Question to our active flight crew.
The EAFR records column / yoke angle and input force . It will be easy to show who was controlling the aircraft at any moment. Do you think that if for example the FO, whilst actively flying the aircraft was the one to reset the switches back to run, in changing to a single hand on the yoke and turning to the switches, there would be any detectable change in input force / angle ? Or would that detail be lost in the noise?
Subjects
EAFR
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July 18, 2025, 00:53:00 GMT
permalink Post: 11924765
Because the preliminary report can only contain verified factual information.
"There has been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB." - This will have been verified by the investigation team fairly rapidly. Verified reportable fact, included in the preliminary report.
This could not have been done by the team in the time available. Bear in mind that the EAFR was not read until almost 2 weeks after the crash. Before that point there would have been little focus on the fuel switches, which were recovered in the run position (verifiable and reported). Once attention was directed to the switches, a small team will form just to forensically examine those switches. They will likely take WEEKS to even begin the detailed examination of the switches. Those switches have been through a crash and a fire. They dare not move them until every possible non-destructive examination technique has been used. What do you test first? just pulling the sleeve will move something. Moving the lever will move the contacts. Did fingerprints survive the fire?. You would want to x-ray them, measure wear on the locking, look at contact position. Electrically test the terminals. Does it need to be opened? They would get examples from the manufacturer and destructively test them.
Yes in the final report they would be in a position to make a statement like that. But in the preliminary - No.
"There has been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB." - This will have been verified by the investigation team fairly rapidly. Verified reportable fact, included in the preliminary report.
This could not have been done by the team in the time available. Bear in mind that the EAFR was not read until almost 2 weeks after the crash. Before that point there would have been little focus on the fuel switches, which were recovered in the run position (verifiable and reported). Once attention was directed to the switches, a small team will form just to forensically examine those switches. They will likely take WEEKS to even begin the detailed examination of the switches. Those switches have been through a crash and a fire. They dare not move them until every possible non-destructive examination technique has been used. What do you test first? just pulling the sleeve will move something. Moving the lever will move the contacts. Did fingerprints survive the fire?. You would want to x-ray them, measure wear on the locking, look at contact position. Electrically test the terminals. Does it need to be opened? They would get examples from the manufacturer and destructively test them.
Yes in the final report they would be in a position to make a statement like that. But in the preliminary - No.
Subjects
EAFR
Fuel (All)
Fuel Cutoff Switches
Preliminary Report
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November 07, 2025, 23:53:00 GMT
permalink Post: 11985044
If that is the lawsuit based on
this filing
, then you're in for a treat. Same crowd that delivered
this 'report'
, which seems to be a mash-up of all the various conspiracy theories (aft EAFR fire damaged so must have been a battery fire? Check).
Disappointing for someone with what seem to be remarkable credentials:
It is technically just garbage.
Disappointing for someone with what seem to be remarkable credentials:
The founder of the organization is Captain Amit Singh, he is a senior management
professional with over 17000 hours on Boeing - 777 and Airbus - 320. He has
also been associated with the start-up of two airlines, viz Air Asia and IndiGo,
and has held the posts of: Chief of Safety, AirAsia, Director Flight Operations,
AirAsia, Chief Pilot Training, IndiGo and Fleet Captain Safety/ Technical
Interglobe Aviation Ltd. He is a Fellow of the Royal Aeronautical Society,
London,
professional with over 17000 hours on Boeing - 777 and Airbus - 320. He has
also been associated with the start-up of two airlines, viz Air Asia and IndiGo,
and has held the posts of: Chief of Safety, AirAsia, Director Flight Operations,
AirAsia, Chief Pilot Training, IndiGo and Fleet Captain Safety/ Technical
Interglobe Aviation Ltd. He is a Fellow of the Royal Aeronautical Society,
London,
Subjects
EAFR
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November 28, 2025, 20:11:00 GMT
permalink Post: 11997382
original source:
https://thefederal.com/category/busi...failure-217674
The Emergency Locator Transmitter (ELT), a critical post-crash distress beacon, was never activated, as per the AAIB report. It was recovered intact in the wreckage, yet it was silent.A CCS/core network failure would not by itself stop the transmission from an ELT’s automatic g-switch — which is a gravity (g) switch with a sensor that detects sudden changes in acceleration (g-forces) that typically occur during a crash.
That is, unless the ELT’s antenna and wiring had melted in a fire — and one possible pointer to that is a Category A fault logged on AI 171’s Nitrogen Generation System (NGS), a safety feature Boeing added to prevent fuel tank fires in the aftermath of the Trans World Airlines Flight 800’s midair explosion due to a central fuel tank ignition in 1996.
The NGS works by continuously flooding the tail fuel tank’s ullage (the empty space above the fuel) with nitrogen-rich air, displacing oxygen and thereby preventing the build-up of flammable vapours.
If the NGS were not functioning, the oxygen levels around the aft-fuel tank bay may have been dangerously high. In that scenario, even a small spark—possibly from an electric arc or surge—could ignite a localised fuel-air vapour fire. That would have burnt the wiring and antenna of the ELT and wiring, connectors, and housing of tail-section black box or the aft Enhanced Airborne Flight Recorder (EAFR). And this scenario would be in line with the AAIB report, which shows the tail section was more structurally intact compared to the nose.
That is, unless the ELT’s antenna and wiring had melted in a fire — and one possible pointer to that is a Category A fault logged on AI 171’s Nitrogen Generation System (NGS), a safety feature Boeing added to prevent fuel tank fires in the aftermath of the Trans World Airlines Flight 800’s midair explosion due to a central fuel tank ignition in 1996.
The NGS works by continuously flooding the tail fuel tank’s ullage (the empty space above the fuel) with nitrogen-rich air, displacing oxygen and thereby preventing the build-up of flammable vapours.
If the NGS were not functioning, the oxygen levels around the aft-fuel tank bay may have been dangerously high. In that scenario, even a small spark—possibly from an electric arc or surge—could ignite a localised fuel-air vapour fire. That would have burnt the wiring and antenna of the ELT and wiring, connectors, and housing of tail-section black box or the aft Enhanced Airborne Flight Recorder (EAFR). And this scenario would be in line with the AAIB report, which shows the tail section was more structurally intact compared to the nose.
There's a good 20m of cabin between the centre fuel tanks (there is no 'aft fuel tank bay' on a 787) and the ELT/aft EAFR which are IIRC more-or-less above the rear doors.
The rest isn't much better.
I also see no mention of the fact that virtually everything in the CCS/CDN/CCRs is at least duplicated.
Last edited by Senior Pilot; 29th November 2025 at 03:07 . Reason: Add source of the quote
Subjects
AAIB (All)
DFDR
EAFR
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