July 12, 2025, 22:46:00 GMT
permalink Post: 11920900
It seems to me that there must have been further dialogue after the bland "I didn't". To have nothing reported after that two-line exchange, until the MAYDAY at 08:09:05, is a highly suspect omission from the interim report. In a two-crew cockpit, facing a sudden dual engine rollback just after rotation, I find it very hard to believe that this two-line exchange was the only interaction captured.
Although published a little later than expected, it has now narrowed the speculator's focus from the wilder theories to the fuel switches.
Air India is not grounded, Boeing engines are not grounded and there are no recommended actions to engine operators and manufacturers.
Although a full verbatim transcript of the CVR could have been published, or even the recording itself, a decision has been made by the investigators not to do so. All we have is two bland paraphrases 'One of the pilots is heard asking the other why did he cutoff' (not even gramatically correct). 'The other pilot responded that he did not do so'.
Sometimes reports are more about what is not in them rather than was is in them.
It seems to me that the missing sections from the recording which would have revealed exact voice timings, language, tone, inflection and urgency which would have answered a lot of the questions on here have been deliberately withheld either temporarily or permanently. It is for the reader to infer why that might be. The investigators know much more but have chosen not to publicise it. I suspect they have more pieces of the jigsaw than we can see but probably not the full picture yet.
Last edited by T28B; 12th July 2025 at 23:06 . Reason: Formatting for ease of reading and pulling out key points
July 12, 2025, 23:06:00 GMT
permalink Post: 11920911
Tdracer has certainly explained that separation of cabling runs etc would have it very improbable that a single cable fault or short would impact both engines simultaneously in the same way. The CVR data is derived from local sensors with a dedicated battery backup, however all the FDR data and the fuel shut off commands are electrical signals which ultimately have a common source in the aircraft power buses. A water ingress into the EE bay at rotate which momentarily shorted all the low voltage buses to higher AC voltage is unlikely but is it unlikely to the same extent.
What bothers me is that message about the stab cutoff switches on the previous flight. It's a bit of a strange coincidence, since those switches are quite close to the fuel switches. I'm thinking that maybe some liquid could have been spilled during the previous flight over the area of the fuel switches and stab cutoff switches. Perhaps it initially affected just the stab switches. Then, during the accident flight, the acceleration and/or the rotation might have caused residual liquid to move and cause some issue for both fuel switches. Then, as the acceleration stopped after the loss of thrust and the aircraft stopped climbing, maybe the liquid moved again and the fuel switches recovered. But I admit this seems very unlikely.
July 12, 2025, 23:13:00 GMT
permalink Post: 11920915
Yes I totally agree, if it was deliberate there would have been a fight to prevent them being turned on again, until it was too late. As a previous post said, during a loss of thrust on both engines, your immediate comment is not \x93why did you cut off\x94 therefore it\x92s reasonable to assume he saw it happen, and then a 10 second fight to restore them ensued.
July 12, 2025, 23:37:00 GMT
permalink Post: 11920930
Reminder: the prelim report didn't say exactly what the pilots said, and I also think it's unlikely that they said it in English anyway.
So there's no value in wondering what motivated one pilot to say "why did you cutoff" because we don't know if that's what was said.
The exact wording in the report is:
Given the need to couch the report's wording in neutral/diplomatic terms (expletives?), and almost certainly to translate the conversation from another language, the inferences being drawn from those lines in the report are going wildly beyond what is reasonable.
So there's no value in wondering what motivated one pilot to say "why did you cutoff" because we don't know if that's what was said.
The exact wording in the report is:
In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff.
The other pilot responded that he did not do so.
The other pilot responded that he did not do so.
July 13, 2025, 08:43:00 GMT
permalink Post: 11921144
The switches were operated at 3s after liftoff\x85exactly the time positive rate would be confirmed\x85so I\x92m still thinking third party isn\x92t the most likely scenario.
July 13, 2025, 09:03:00 GMT
permalink Post: 11921160
I see 3 meaningful explanations roughly by order of probability
- Switches moved deliberately - evidenced by the specific question "why did you cutoff" and circumstanced by this being the most vulnerable phase of flight to do such a thing
- Switches moved accidentally eg., 'action-slip' - is there a precedent for not 1 but both switches of this type in any similar aircraft being cut off during routine operations?
- Switches failed mechanically or electronically - the recovered switches were in the position consistent with flight data, timing data is consistent with manual 1-by-1 movement
July 13, 2025, 09:15:00 GMT
permalink Post: 11921169
I don't see any evidence here. The report doesn't mention any callout of positive rate or request for gear up. The cutoff switches were moved ~3 seconds after wheels leaving the ground which would have been just before or at roughly the same time as the callout. The report did not say "pilot flying requested gear up and then the switches were moved to cutoff". There is also no evidence of a 3rd person and I'm not even sure how that would make a difference.
I see 3 meaningful explanations roughly by order of probability
I see 3 meaningful explanations roughly by order of probability
- Switches moved deliberately - evidenced by the specific question "why did you cutoff" and circumstanced by this being the most vulnerable phase of flight to do such a thing
- Switches moved accidentally eg., 'action-slip' - is there a precedent for not 1 but both switches of this type in any similar aircraft being cut off during routine operations?
- Switches failed mechanically or electronically - the recovered switches were in the position consistent with flight data, timing data is consistent with manual 1-by-1 movement
(1) It\x92s still a likely response to ask that question if your colleague had just switched them off by action-slip.
(2) See my post above. Routine use of these switches is in one \x93event\x94\x85below OAT 40C you start both simultaneously and at shutdown you operate one straight after another.
(3) The interim report seems to leave out all information on verbal exchanges not specifically involved with a response to the abnormal situation.
Not saying you aren\x92t correct, but it doesn\x92t change the order of likelihood in my mind.
July 13, 2025, 10:23:00 GMT
permalink Post: 11921207
Not sure if this is helpful for anyone or not but I thought a visual view of the timeline of events might be useful, in seconds since V1.
I've assumed 1Hz for the switch sampling rate and >1Hz for everything else (could be wrong) to give windows for the switch state changes.
I've also added in the ADS-B relevant data, although made no attempt to work out whether these timestamps are synchronised or not, so take them as you will.
I have assumed the cutoff is in chronological order from the report, albeit I have ignored the RAT supply timestamp in terms of chronology from the CVR recording, as that statement in the report at that time may just be due to contextual nature of the statement, rather than it happening prior to the RAT power supply. This gives a window for potentially when that statement was made (assuming also that it was made prior to reversing cutoff).
Really highlights how knowing precisely when the why did you cutoff" question was asked might have provided more clarity and less speculation as to how those fateful seconds played out
And it would have helped to know if Positive rate / Gear Up was called ... and when
Last edited by unworry; 13th July 2025 at 12:19 .
July 13, 2025, 11:13:00 GMT
permalink Post: 11921238
I\x92d counter that order of likelihood by suggesting
(1) It\x92s still a likely response to ask that question if your colleague had just switched them off by action-slip.
(2) See my post above. Routine use of these switches is in one \x93event\x94\x85below OAT 40C you start both simultaneously and at shutdown you operate one straight after another.
(3) The interim report seems to leave out all information on verbal exchanges not specifically involved with a response to the abnormal situation.
Not saying you aren\x92t correct, but it doesn\x92t change the order of likelihood in my mind.
(1) It\x92s still a likely response to ask that question if your colleague had just switched them off by action-slip.
(2) See my post above. Routine use of these switches is in one \x93event\x94\x85below OAT 40C you start both simultaneously and at shutdown you operate one straight after another.
(3) The interim report seems to leave out all information on verbal exchanges not specifically involved with a response to the abnormal situation.
Not saying you aren\x92t correct, but it doesn\x92t change the order of likelihood in my mind.
By precedent in routine operations I mean: is there a single example of these switches being cut off at takeoff like this? There is precedent for the wrong engine being shut down in a fire sure, and there is perhaps precedent for mishaps with the fuel switches in other cockpit layouts - but in the case of this layout, with this model of switch or even this 'style' of switch and placement, I cannot find a single example that would come close to the level of catastrophic action slip of pulling out and setting to cutoff both switches one by one.
I think the preliminary report is supposed to present all factual information - they could have left out "why did you cutoff / I did not" - I could understand if they left out sounds that could be ambiguous, perhaps indicating a struggle but not clear enough to present as fact. However, "positive rate / gear up" followed by 2 switches instead of gear handle is completely factual and relevant information, to exclude it makes no sense.
July 13, 2025, 11:24:00 GMT
permalink Post: 11921244
It actually doesn\x92t matter who said it for the purposes of diagnosing deliberate action, if it\x92s someone trying to cover their tracks and deflect blame onto the other person it still represents cognition that the movement of the switches was a deliberate act and will have been recorded as such.
The only known fact is that engines for some reason were shut down. The other known fact is that there is a recorded indication that the start lever command was recorded as both cutoff in short succession then followed by idle detent causing a restart attempt.
I think the key unknowns here are important.
1. Was the start lever position recorded, or only the electrical signal? My money is on an electrical signal not position, therefore the manual positioning of the start levers is not conclusively proven.
2. The bulletin for locking mechanism for the start levers has been mentioned in the preliminary report. This is a huge unknown. Did that mean that in a failure that the levers could both move into cutoff at the same time? This occurred exactly as the aircraft was rotating and increasing pitch.
3. The information from the CVR if taken at face value must not be discounted. No pilot actually confirmed conclusively seeing the other move the switch. This could have been an assumption noticing an engine failure, seeing the start levers positions in cutoff or indeed seeing the start levers moved deliberately. This is a huge critical unknown.
4. One pilot asked 'why did you cutoff' and the other responded 'I didn't'. This is not a confirmation of anything for sure. In fact it is equally a suggestion no pilot moved the switches, equally as it is saying they did. This is not conclusive. This raises an important question, was this genuine, did either pilot have any reason in their life to attempt to do this and then cover their actions? There is zero suggestion here either way, but hopefully investigators will already be looking at their backgrounds and state of affairs.
5. There is no indication who or what commanded the engines back to idle detent again. There is proof of both engines attempting to restart. I would take this as confirmation of teamwork existing on the flight deck, and this would suggest a lack of deliberate interference by either pilot. Should that have been deliberately done, so much more could have happened. It just hasn't been alluded to in the preliminary report.
My own impression is that it did not appear to be a situation of a deliberate act to crash. I say this as they appear to have both tried to save the aircraft and immediately restart the engines and recover taking some critical timely actions demonstrating competent reaction.
The timing of the commanding fuel to cutoff is critical imo. The aircraft was pitching. If an accidental command to cutoff occurred then I feel this however unlikely would have been made instead of another action. The only likely thing happening at that exact time or due 2-3 seconds after lift off was gear up. The CVR and recorded timing of engine failure in relation to that challenge and response in SOP will be key imo. Did the challenge for gear up occur before the idle detent electrical signals? Also, the focus should be on that bulletin for the locking mechanism for the start levers.
I just cannot imagine an experienced crew doing this by accident and the information just doesn't suggest a deliberate act.
My post is just to highlight huge lists of unknowns. The media appears to have made their mind up that the flight crew did this. I just highlight that is definitely not confirmed yet. We have a whole list of unknowns and conflicting communication that raises more questions than they solve.
I would urge zero conclusions be made, and RIP the crew and passengers. There are zero conclusions to what happened yet in my opinion, and I think the suggestion to relatives of the flight crew and families tragically killed that this is a known pilot deliberate action simply cannot be made at this point. We must not blame the flight crew prematurely or pretend we know what happened. I think the media should take note and back off from all the assumptions.
Last edited by Captain Biggles 101; 14th July 2025 at 09:29 .
July 13, 2025, 11:27:00 GMT
permalink Post: 11921247
AI171 Thread by Subject
I have rebuilt the site that organises this thread by subject here:
https://paulross.github.io/pprune-th...171/index.html
It studies 3703 posts (and discards 1043 of them).
Changes:
- Add subjects: "Action slip", "AvHerald", "Human Factors", 'Pilot "Why did you cut off"'.
- Build threads up to July 13, 2025, 10:57:00 (built on July 13, 2025, 12:02:17).
Project is here: https://github.com/paulross/pprune-threads
Raise issues here https://github.com/paulross/pprune-threads/issues or PM me.
It studies 3703 posts (and discards 1043 of them).
Changes:
- Add subjects: "Action slip", "AvHerald", "Human Factors", 'Pilot "Why did you cut off"'.
- Build threads up to July 13, 2025, 10:57:00 (built on July 13, 2025, 12:02:17).
Project is here: https://github.com/paulross/pprune-threads
Raise issues here https://github.com/paulross/pprune-threads/issues or PM me.
July 13, 2025, 11:28:00 GMT
permalink Post: 11921248
(1) is true I give you that, but there is no followup "I didn't.. oh crap", denial is a reasonable response if you truly haven't registered doing something, but it is also a reasonable response if you want to confuse to delay
By precedent in routine operations I mean: is there a single example of these switches being cut off at takeoff like this? There is precedent for the wrong engine being shut down in a fire sure, and there is perhaps precedent for mishaps with the fuel switches in other cockpit layouts - but in the case of this layout, with this model of switch or even this 'style' of switch and placement, I cannot find a single example that would come close to the level of catastrophic action slip of pulling out and setting to cutoff both switches one by one.
I think the preliminary report is supposed to present all factual information - they could have left out "why did you cutoff / I did not" - I could understand if they left out sounds that could be ambiguous, perhaps indicating a struggle but not clear enough to present as fact. However, "positive rate / gear up" followed by 2 switches instead of gear handle is completely factual and relevant information, to exclude it makes no sense.
By precedent in routine operations I mean: is there a single example of these switches being cut off at takeoff like this? There is precedent for the wrong engine being shut down in a fire sure, and there is perhaps precedent for mishaps with the fuel switches in other cockpit layouts - but in the case of this layout, with this model of switch or even this 'style' of switch and placement, I cannot find a single example that would come close to the level of catastrophic action slip of pulling out and setting to cutoff both switches one by one.
I think the preliminary report is supposed to present all factual information - they could have left out "why did you cutoff / I did not" - I could understand if they left out sounds that could be ambiguous, perhaps indicating a struggle but not clear enough to present as fact. However, "positive rate / gear up" followed by 2 switches instead of gear handle is completely factual and relevant information, to exclude it makes no sense.
July 13, 2025, 11:43:00 GMT
permalink Post: 11921256
@Maybeitis,
how about we leave the total redesign of the fuel switch locations and operation (which have been moved billions of times in thousands of aircraft without a hitch) until the final report is out.
These were deliberately moved. It wasn't a brain-fart. Unless the interim report omits crew calls which turn the scenario on it's head.
These were deliberately moved. It wasn't a brain-fart. Unless the interim report omits crew calls which turn the scenario on it's head.
Firstly, you'll have seen plenty of things to disprove the "without a hitch" in this thread alone , and as a professional pilot you'll no doubt know of many others - including switches moved in-flight as a brain-fart , or switches moved by things like falling objects. Waiting for the final report may tell us if it would have made a difference in this case, but the lower tier of the safety pyramid (non-severe outcomes) is definitely already populated with plenty of examples of "hitches".
Secondly, I'm absolutely inclined to agree that the switches were moved deliberately (though perhaps absent-mindedly), but I'm genuinely shocked and baffled that you are already willing to assert that "It wasn't a brain-fart". Perhaps those words were typed in haste and you didn't re-read what you had written? (A brain-fart, in other words.)
You don\x92t \x93flick switches in the Sim\x94 for no apparent reason.
Even Indian sources are now reporting on the possibility of intent.
https://www.ndtv.com/india-news/air-...-probe-8864239
Even Indian sources are now reporting on the possibility of intent.
https://www.ndtv.com/india-news/air-...-probe-8864239
July 13, 2025, 11:50:00 GMT
permalink Post: 11921259
Latest version:
July 13, 2025, 15:02:00 GMT
permalink Post: 11921377
With the greatest respect, I don't think any deliberate act has been proven. Allocating blame on assumptions should be avoided. People should work on facts, and then unconfirmed assumptions.
The only known fact is that engines for some reason were shut down. The other known fact is that there is a recorded indication that the start lever command was recorded as both cutoff in short succession then followed by idle detent causing a restart attempt.
I think the key unknowns here are important.
1. Was the start lever position recorded, or only the electrical signal? My money is on an electrical signal not position, therefore the manual positioning of the start levers is not conclusively proven.
2. The bulletin for locking mechanism for the start levers has been mentioned in the preliminary report. This is a huge unknown. Did that mean that in a failure that the levers could both move into cutoff at the same time? This occurred exactly as the aircraft was rotating and increasing pitch.
3. The information from the CVR if taken at face value must not be discounted. No pilot actually confirmed conclusively seeing the other move the switch. This could have been an assumption noticing an engine failure, seeing the start levers positions in cutoff or indeed seeing the start levers moved deliberately. This is a huge critical unknown.
4. One pilot asked 'why did you cutoff' and the other responded 'I didn't'. This is not a confirmation of anything for sure. In fact it is equally a suggestion nobody pilot moved the switches as it is saying they did. This is not conclusive. This raises an important question, was this genuine, did either pilot have any reason in their life to attempt to do this and then cover their actions? There is zero suggestion here either way, but hopefully investigators will already be looking at their backgrounds and state of affairs.
5. There is no indication who or what commanded the engines back to idle detent again. There is proof of both engines attempting to restart. I would take this as confirmation of teamwork existing on the flight deck, and this would suggest a lack of deliberate interference by either pilot. Should that have been deliberately done, so much more could have happened. It just hasn't been alluded to in the preliminary report.
My own impression is that it did not appear to be a situation of a deliberate act to crash. I say this as they appear to have both tried to save the aircraft and immediately restart the engines and recover taking some critical timely actions demonstrating competent reaction.
The timing of the commanding fuel to cutoff os critical imo. The aircraft was pitching. If an accidental command to cutoff occurred then I feel this however unlikely would have been made instead of another action. The only likely thing happening at that exact time or due 2-3 seconds after lift off was gear up. The CVR and recorded timing of engine failure in relation to that challenge and response in SOP will be key imo. Did the challenge for gear up occur before the idle detent electrical signals? Also, the focus should be on that bulletin for the locking mechanism for the start levers.
I just cannot imagine an experienced crew doing this by accident and the information just doesn't suggest a deliberate act.
My post is just to highlight huge lists of unknowns. The media appears to have made their mind up that the flight crew did this. I just highlight that is definitely not confirmed yet. We have a whole list of unknowns and conflicting communication that raises more questions than they solve.
I would urge zero conclusions be made, and RIP the crew and passengers. There are zero conclusions to what happened yet in my opinion, and I think the suggestion to relatives of the flight crew and families tragically killed that this is a known pilot deliberate action simply cannot be made at this point. We must not blame the flight crew prematurely or pretend we know what happened. I think the media should take note and back off from all the assumptions.
The only known fact is that engines for some reason were shut down. The other known fact is that there is a recorded indication that the start lever command was recorded as both cutoff in short succession then followed by idle detent causing a restart attempt.
I think the key unknowns here are important.
1. Was the start lever position recorded, or only the electrical signal? My money is on an electrical signal not position, therefore the manual positioning of the start levers is not conclusively proven.
2. The bulletin for locking mechanism for the start levers has been mentioned in the preliminary report. This is a huge unknown. Did that mean that in a failure that the levers could both move into cutoff at the same time? This occurred exactly as the aircraft was rotating and increasing pitch.
3. The information from the CVR if taken at face value must not be discounted. No pilot actually confirmed conclusively seeing the other move the switch. This could have been an assumption noticing an engine failure, seeing the start levers positions in cutoff or indeed seeing the start levers moved deliberately. This is a huge critical unknown.
4. One pilot asked 'why did you cutoff' and the other responded 'I didn't'. This is not a confirmation of anything for sure. In fact it is equally a suggestion nobody pilot moved the switches as it is saying they did. This is not conclusive. This raises an important question, was this genuine, did either pilot have any reason in their life to attempt to do this and then cover their actions? There is zero suggestion here either way, but hopefully investigators will already be looking at their backgrounds and state of affairs.
5. There is no indication who or what commanded the engines back to idle detent again. There is proof of both engines attempting to restart. I would take this as confirmation of teamwork existing on the flight deck, and this would suggest a lack of deliberate interference by either pilot. Should that have been deliberately done, so much more could have happened. It just hasn't been alluded to in the preliminary report.
My own impression is that it did not appear to be a situation of a deliberate act to crash. I say this as they appear to have both tried to save the aircraft and immediately restart the engines and recover taking some critical timely actions demonstrating competent reaction.
The timing of the commanding fuel to cutoff os critical imo. The aircraft was pitching. If an accidental command to cutoff occurred then I feel this however unlikely would have been made instead of another action. The only likely thing happening at that exact time or due 2-3 seconds after lift off was gear up. The CVR and recorded timing of engine failure in relation to that challenge and response in SOP will be key imo. Did the challenge for gear up occur before the idle detent electrical signals? Also, the focus should be on that bulletin for the locking mechanism for the start levers.
I just cannot imagine an experienced crew doing this by accident and the information just doesn't suggest a deliberate act.
My post is just to highlight huge lists of unknowns. The media appears to have made their mind up that the flight crew did this. I just highlight that is definitely not confirmed yet. We have a whole list of unknowns and conflicting communication that raises more questions than they solve.
I would urge zero conclusions be made, and RIP the crew and passengers. There are zero conclusions to what happened yet in my opinion, and I think the suggestion to relatives of the flight crew and families tragically killed that this is a known pilot deliberate action simply cannot be made at this point. We must not blame the flight crew prematurely or pretend we know what happened. I think the media should take note and back off from all the assumptions.
Kudos to the crew for trying to re-light the engines so quickly.
My 10 cents is on the switches and there is not a aireworthiness directive out there for nothing.
July 14, 2025, 04:55:00 GMT
permalink Post: 11921857
Just to clarify, I'm not aware of any confirmation at this point that the Fuel Cutoff switches were
physically
moved from RUN to CUTOFF and back again.
We do have evidence that the FDR, thus the databus, received signals that the Fuel Cutoff switches were in the RUN position, then the signals changed to CUTOFF one second apart, and then back to RUN at four second intervals.
In the absence of video, we could only use CVR data to determine that the switches were physically moved - either through flight crew conversation or sound of switches being moved.
When the PF asks why the PNF "Why did you cut off" we don't know whether he concluded the fuel was cutoff by checking the physical position of the switches or through instrument annunciations.
I accept that with sampling rates the physical movement of switches to CUTOFF at one second intervals could be logically explained. I can understand why there would be such an interval between physically moving the two switches back to RUN, unless there was some sort of struggle which presumably would be easily detectable on CVR.
Unless I've missed something, I'm not ready to conclude that the switches ever physically moved.
We do have evidence that the FDR, thus the databus, received signals that the Fuel Cutoff switches were in the RUN position, then the signals changed to CUTOFF one second apart, and then back to RUN at four second intervals.
In the absence of video, we could only use CVR data to determine that the switches were physically moved - either through flight crew conversation or sound of switches being moved.
When the PF asks why the PNF "Why did you cut off" we don't know whether he concluded the fuel was cutoff by checking the physical position of the switches or through instrument annunciations.
I accept that with sampling rates the physical movement of switches to CUTOFF at one second intervals could be logically explained. I can understand why there would be such an interval between physically moving the two switches back to RUN, unless there was some sort of struggle which presumably would be easily detectable on CVR.
Unless I've missed something, I'm not ready to conclude that the switches ever physically moved.
July 14, 2025, 14:31:00 GMT
permalink Post: 11922258
The only distinction the report makes is that the question was 'why did you cut off' rather than 'did you cut off', which suggests one of the pilots saw the other cut the switches, which in turn suggests either (a) the pilot who did the cutoff had done it accidentally and wasn't aware of it, or (b) the pilot who did the cutoff was well aware of what they did but then lied about it despite having clearly been seeing doing it.
Given the question was 'why', it seems equally plausible that it was the PF Kunder who transitioned the switches accidentally as part of some muscle memory blunder, and it was the PM Sabharwal who asked Kunder why he cutoff, who then replied that he didn't, because the fact he'd made the mistake hadn't registered.
OTOH, it might just be a sloppy transcription.
While depressed people get lost in their thoughts, this would have been a total reversal of his caring nature. It's just another factor that just doesn't make sense.
I totally agree with this, it makes no sense at all, especially after his 'just one or two more flights' statement. The guy had already moved cities to help look after his father, and was considering retiring early to have even more time to dedicate. Again, for me, this points to a blunder by Kunder.
Last edited by pampel; 14th July 2025 at 15:17 . Reason: made distinction in question more clear
July 15, 2025, 00:16:00 GMT
permalink Post: 11922589
I'm pilot flying, so my gaze and attention is firmly out the front rotating to the planned takeoff attitude.
Initially and in no particular order:
- I would feel the loss of thrust as a sudden loss of acceleration.
- There would be a significant nose down pitch trim change that I would feel through the yoke.
- There would be lots of audio cues: Changes in engine and air conditioning noises. Lots of click-clacking as electrical relays change state with the loss of electrical power.
My eyes would be drawn inside. I would notice blanking of some of the displays and then look to the EICAS display. My first thought would be probably that we have suffered a major electrical malfunction. There would be lots of messages. I'm not B787 endorsed, but presumably close to the top of the messages would be ENG SHUTDOWN. This message is shown when 'Both engines were shut down by the fuel control switches or the engine fire switches.'
I think I would then look at the fuel control switches and seeing them both in the cutoff position I would say 'why did you cutoff' or stronger words to that effect.
After that it all depends on the response of the other pilot. If they are uncooperative, I would be putting the fuel control switches back to run. All whilst frequently checking and adjusting my flight path.
Last edited by Bleve; 15th July 2025 at 00:39 .
July 15, 2025, 17:02:00 GMT
permalink Post: 11923088
After all the analysis on PPRuNE, fuel switch failure (well, dual switch failure, at practically the same time) seems so unlikely it's no longer worthy of consideration. However, I'm still open to the idea of a failure elsewhere that may have signalled the fuel switches had transistioned from Run to Cutoff wthout physical movement of either switch. Why? Firstly, because of this (taken from the preliminary report)
The STAB cutout switches are located next to the Fuel cutoff switches. What did Air India’s on duty AME do as part of their troubleshooting? Were panels removed to gain access to the rear of the switches and wiring? What about wiring and data connections elsewhere? What may have been disconnected/disturbed as part of this process? Do the STAB cutout switches and Fuel cutoff switches share any connectors that could have been inadvertantly cross-connected? Etc. It would not be the first time that an engineer had innocently done something that later caused an accident. And I haven't read anything about possible nefarious action by a (disgruntled?) engineer - but I've seen lots of accusations directed at the pilot(s)...
Secondly, the preliminary report's version of (part of) the conversation in the cockpit -
Until proven beyond reasonable doubt I'm chosing to take the cockpit conversation at face value, because I really don't want to believe any of the following scenarios:
A) one of the pilots lied
B) one of the pilots attempted to deflect blame onto the other pilot for the benefit of the CVR
C) One of the pilots unknowingly operated the fuel cutoff switches.
D) One of the pilots deliberately operated the fuel cutoff switches.
It is all too easy to blame one of the pilots when in reality no one outside of the official investigation may yet know what most likely happened.
The crew of the previous flight (AI423) had made Pilot Defect Report (PDR) entry for status
message “STAB POS XDCR” in the Tech Log. The troubleshooting was carried out as per
FIM by Air India’s on duty AME, and the aircraft was released for flight at 0640 UTC.
message “STAB POS XDCR” in the Tech Log. The troubleshooting was carried out as per
FIM by Air India’s on duty AME, and the aircraft was released for flight at 0640 UTC.
The STAB cutout switches are located next to the Fuel cutoff switches. What did Air India’s on duty AME do as part of their troubleshooting? Were panels removed to gain access to the rear of the switches and wiring? What about wiring and data connections elsewhere? What may have been disconnected/disturbed as part of this process? Do the STAB cutout switches and Fuel cutoff switches share any connectors that could have been inadvertantly cross-connected? Etc. It would not be the first time that an engineer had innocently done something that later caused an accident. And I haven't read anything about possible nefarious action by a (disgruntled?) engineer - but I've seen lots of accusations directed at the pilot(s)...
Secondly, the preliminary report's version of (part of) the conversation in the cockpit -
In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff.
The other pilot responded that he did not do so.
The other pilot responded that he did not do so.
A) one of the pilots lied
B) one of the pilots attempted to deflect blame onto the other pilot for the benefit of the CVR
C) One of the pilots unknowingly operated the fuel cutoff switches.
D) One of the pilots deliberately operated the fuel cutoff switches.
It is all too easy to blame one of the pilots when in reality no one outside of the official investigation may yet know what most likely happened.
July 16, 2025, 14:49:00 GMT
permalink Post: 11923781
What are the chances of both switches going bad on the same flight?
As stated many times previously the throttle quadrant was replaced well after the 2018 SB.
Quadrants can be replaced for a myriad of reasons, according to the report none that had anything to do with the switches.
If there was even a remote suspicion of the switches being at fault an emergency AD would already have been issued.
As stated many times previously the throttle quadrant was replaced well after the 2018 SB.
Quadrants can be replaced for a myriad of reasons, according to the report none that had anything to do with the switches.
If there was even a remote suspicion of the switches being at fault an emergency AD would already have been issued.
If there was a 0,0001 percent chance the switches were faulty and could have moved because of gravity of an object hitting is, there would be a safety bulletin released to all B787 operators
There has not been such a bulletin.
The reason why the report does not mention which of the pilots ask " why did you cutoff ? " is unknown. We also do not know why it was written the switches ' transitioned' instead of ' moved' .
My guess it was either for political reasons or because of a possible criminal investigation.
For a pilot there is no reason to set both switches to cutoff without any reason. There was no engine fire. There was no discussion in the cockpit about using the switches.
Nothing. A mistake is extremely unlikely. There is no reason why the hands of a pilot needs to be near the switches. I do not believe in a brain fart.