June 28, 2025, 17:04:00 GMT
permalink Post: 11912578
I am not certain on that. Remember the 737 didn't have them on the standby bus (Jeju). The NTSB doc states they're powered from the L/R 28VDC buses on the 787.
This shows the centre TRUs can only power the instrument buses not the L/R DC buses, the RAT can't really power the right TRU without powering both R1/R2 buses, and powering the left TRU would require powering the left 235/115 ATU which would probably be a lot of magnetising current even if not much actual load. The contactor naming supports that.
My money is on the L/R DC buses being unpowered in RAT operation; only the CA/FO instrument buses and the 235VAC backup bus.
This shows the centre TRUs can only power the instrument buses not the L/R DC buses, the RAT can't really power the right TRU without powering both R1/R2 buses, and powering the left TRU would require powering the left 235/115 ATU which would probably be a lot of magnetising current even if not much actual load. The contactor naming supports that.
My money is on the L/R DC buses being unpowered in RAT operation; only the CA/FO instrument buses and the 235VAC backup bus.
Last edited by D Bru; 28th June 2025 at 17:06 . Reason: deleting a repeat image of the elec system
June 28, 2025, 18:19:00 GMT
permalink Post: 11912613
Not useless
much netter than\x85nothing. Thats most certainly the background to the new regulations to battery backup.
June 28, 2025, 18:53:00 GMT
permalink Post: 11912625
FAA requirements and the discussion/changes that resulted from the initial NPRM here -
https://www.federalregister.gov/docu...er-regulations
June 28, 2025, 19:12:00 GMT
permalink Post: 11912634
That's exactly why I would really recommend reading through the NTSB FDR report on the 2013 JA829J Boston incident helpfully posted by
EDLB
. There's potentially a wealth of data concerning a to me at least surprisingly number of 2000 of parameters written on a 787 EAFR, that is that at least if there's elec power. Even the 10 min RIPS is useless if there's no data sent from electrically shut off systems.
Auxiliary Power Unit Battery Fire Japan Airlines Boeing 787-8, JA829J Boston, Massachusetts January 7, 2013
June 29, 2025, 15:01:00 GMT
permalink Post: 11913074
By the time you're down to EMER GEN you usually know what the problem is and most systems with parameters that could be recorded on the FDR are unpowered so what's the point of trying. The CVR with a RIPS at least helps us to try understand how or why the events to regain control after that failed.
June 30, 2025, 06:50:00 GMT
permalink Post: 11913386
Yes positively. In the doc I posted above page 16
https://data.ntsb.gov/Docket/Documen...man-Master.PDF
Eng1_Fuel_cutoff
Eng2_Fuel_cutoff
You get a good impression about the overwhelming wealth of parameters.
https://data.ntsb.gov/Docket/Documen...man-Master.PDF
Eng1_Fuel_cutoff
Eng2_Fuel_cutoff
You get a good impression about the overwhelming wealth of parameters.
June 30, 2025, 13:12:00 GMT
permalink Post: 11913614
* as for why not before, probably because it didn't happen that way or in Boeing's worst nightmare some weird corner case in the software that does this if certain parameters are in rare combination.
June 30, 2025, 13:20:00 GMT
permalink Post: 11913619
If rigorously applied, an "engine thrust balancer" would cause the good engine to fail if something happened to the other one. Surely there is some logic in there somewhere to give up and disconnect past a certain amount of adjustment??
* as for why not before, probably because it didn't happen that way or in Boeing's worst nightmare some weird corner case in the software that does this if certain parameters are in rare combination.
* as for why not before, probably because it didn't happen that way or in Boeing's worst nightmare some weird corner case in the software that does this if certain parameters are in rare combination.
(As I don't fly the 787, I may be missing something basic on how the systems work).
June 30, 2025, 13:35:00 GMT
permalink Post: 11913630
If rigorously applied, an "engine thrust balancer" would cause the good engine to fail if something happened to the other one. Surely there is some logic in there somewhere to give up and disconnect past a certain amount of adjustment??
* as for why not before, probably because it didn't happen that way or in Boeing's worst nightmare some weird corner case in the software that does this if certain parameters are in rare combination.
* as for why not before, probably because it didn't happen that way or in Boeing's worst nightmare some weird corner case in the software that does this if certain parameters are in rare combination.
June 30, 2025, 14:42:00 GMT
permalink Post: 11913673
I am not aware of any requirement for a DFDAU (or equivalent) to store any data. I say "or equivalent" because in B717 the DFDAU is not an LRU. It is a functional partition of the VIA.
It's not clear to me that 787 EAFR even requires an external DFDAU. The GE EAFR does not -
"Provides Flight Data Acquisition function of ARINC 664 p7 data parameters \x96 No need for a Digital Flight Data Acquisition Unit (DFDAU)."
ref https://www.geaerospace.com/sites/de...rder-3254F.pdf
It's not clear to me that 787 EAFR even requires an external DFDAU. The GE EAFR does not -
"Provides Flight Data Acquisition function of ARINC 664 p7 data parameters \x96 No need for a Digital Flight Data Acquisition Unit (DFDAU)."
ref https://www.geaerospace.com/sites/de...rder-3254F.pdf
July 11, 2025, 21:48:00 GMT
permalink Post: 11919851
Again, you can not conclude that from the report.
Different inputs are sampled at different rates. Some very basic info here: https://scaledanalytics.com/2023/04/...uses-767-data/
It's highly likely switch positions are only sampled at 1Hz, and not at 100 Hz. For engine parameters you'll likely want a higher sample rate, as the whole engine could go from perfectly fine to exploded in less than a second.
If you had something like:
08:08:42.96 UTC: cut off switch 1
08:08:43.01 UTC: cut off switch 2
It would likely be recorded as:
08:08:42 UTC: cut off switch 1
08:08:43 UTC: cut off switch 2
Leading you to believe there was one second between these 2 actions, whereas it was actually only 50ms.
Different inputs are sampled at different rates. Some very basic info here: https://scaledanalytics.com/2023/04/...uses-767-data/
It's highly likely switch positions are only sampled at 1Hz, and not at 100 Hz. For engine parameters you'll likely want a higher sample rate, as the whole engine could go from perfectly fine to exploded in less than a second.
If you had something like:
08:08:42.96 UTC: cut off switch 1
08:08:43.01 UTC: cut off switch 2
It would likely be recorded as:
08:08:42 UTC: cut off switch 1
08:08:43 UTC: cut off switch 2
Leading you to believe there was one second between these 2 actions, whereas it was actually only 50ms.
July 11, 2025, 23:12:00 GMT
permalink Post: 11919974
OK, a couple of informed comments, again with the disclaimer that I have very little first hand knowledge of the 787.
Every single engine parameter I've seen on a DFDR readout has been recorded at 1/second (most parameters), or slower. I've never seen an engine parameter recorded at more than once/second.
The recorder doesn't do an instantaneous snapshot - it cycles through the thousands of recorded parameters. So a once second difference on the data could - in reality - be anywhere from 0.01 seconds to 1.99 seconds. If it matters, a deep dive into the avionics and FDR logic could narrow that time interval down. That being said, moving both switches to cutoff could happen in about a second. The switches make a rather distinct noise (especially if moved rapidly) so the CVR should give better resolution.
There have been instances in the past where the locking tab on the switch has been broken or 'worn down' from heavy use. But that's been seen on very high cycle aircraft - usually 737s that fly short hops. No memory of ever hearing of an issue with relatively new 787s that are - by nature - long range aircraft and don't get a lot of cycles.
On the 747-400, the fuel switches are a 'break before make' design with a distinct gap of ~0.050 seconds during a normal switch cycle (it's a long, somewhat painful story about why I know that...). I don't know the specifics of the 787, but I'd be very surprised if it's any different.
BTW, if the investigators had reason to believe the switches somehow moved on their own, I think a fleet wide inspection would have been ordered by now.
I keep coming back to my 'muscle memory' hypothesis...
Every single engine parameter I've seen on a DFDR readout has been recorded at 1/second (most parameters), or slower. I've never seen an engine parameter recorded at more than once/second.
The recorder doesn't do an instantaneous snapshot - it cycles through the thousands of recorded parameters. So a once second difference on the data could - in reality - be anywhere from 0.01 seconds to 1.99 seconds. If it matters, a deep dive into the avionics and FDR logic could narrow that time interval down. That being said, moving both switches to cutoff could happen in about a second. The switches make a rather distinct noise (especially if moved rapidly) so the CVR should give better resolution.
There have been instances in the past where the locking tab on the switch has been broken or 'worn down' from heavy use. But that's been seen on very high cycle aircraft - usually 737s that fly short hops. No memory of ever hearing of an issue with relatively new 787s that are - by nature - long range aircraft and don't get a lot of cycles.
On the 747-400, the fuel switches are a 'break before make' design with a distinct gap of ~0.050 seconds during a normal switch cycle (it's a long, somewhat painful story about why I know that...). I don't know the specifics of the 787, but I'd be very surprised if it's any different.
BTW, if the investigators had reason to believe the switches somehow moved on their own, I think a fleet wide inspection would have been ordered by now.
I keep coming back to my 'muscle memory' hypothesis...
July 12, 2025, 08:15:00 GMT
permalink Post: 11920330
Speculation is naturally going in a particular direction towards deliberate action, but it gives me some pause as to whether this actually makes sense as a pre-meditated scheme, and I don't know either way.
Now, perhaps this is a question that shouldn't actually be answered for various good reasons, so more a prompt to consider, but if you were going to set about doing this intentionally, is the probability of the desired outcome actually high enough to commit to this specific course of action, out of all the possibilities available? Perhaps not in this specific environment, but modern survivability in relatively low energy accidents is remarkably high.
In this incident, prior to the release of the report, we have previously remarked that the crew seemed to have done the best they could with it and got unlucky with the circumstances - the buildings, essentially. For me that also raises a question of how carefully planned & rehearsed such a plan would have to be - the breadth of timing parameters where this would 'work' or not.
Now, perhaps this is a question that shouldn't actually be answered for various good reasons, so more a prompt to consider, but if you were going to set about doing this intentionally, is the probability of the desired outcome actually high enough to commit to this specific course of action, out of all the possibilities available? Perhaps not in this specific environment, but modern survivability in relatively low energy accidents is remarkably high.
In this incident, prior to the release of the report, we have previously remarked that the crew seemed to have done the best they could with it and got unlucky with the circumstances - the buildings, essentially. For me that also raises a question of how carefully planned & rehearsed such a plan would have to be - the breadth of timing parameters where this would 'work' or not.
July 12, 2025, 22:25:00 GMT
permalink Post: 11920886
1 second delay
Again, you can not conclude that from the report.
Different inputs are sampled at different rates. Some very basic info here:
It's highly likely switch positions are only sampled at 1Hz, and not at 100 Hz. For engine parameters you'll likely want a higher sample rate, as the whole engine could go from perfectly fine to exploded in less than a second.
If you had something like:
08:08:42.96 UTC: cut off switch 1
08:08:43.01 UTC: cut off switch 2
It would likely be recorded as:
08:08:42 UTC: cut off switch 1
08:08:43 UTC: cut off switch 2
Leading you to believe there was one second between these 2 actions, whereas it was actually only 50ms.
Different inputs are sampled at different rates. Some very basic info here:
It's highly likely switch positions are only sampled at 1Hz, and not at 100 Hz. For engine parameters you'll likely want a higher sample rate, as the whole engine could go from perfectly fine to exploded in less than a second.
If you had something like:
08:08:42.96 UTC: cut off switch 1
08:08:43.01 UTC: cut off switch 2
It would likely be recorded as:
08:08:42 UTC: cut off switch 1
08:08:43 UTC: cut off switch 2
Leading you to believe there was one second between these 2 actions, whereas it was actually only 50ms.
Last edited by AK1969; 13th July 2025 at 00:41 .
July 12, 2025, 22:55:00 GMT
permalink Post: 11920904
If it was a wire strand in the wrong place, that would fit all the facts we know. (Not saying it was, only that it fits)
If you think the timing doesn\x92t quite make, bear in mind the 2 seconds error of margin between any 2 registered parameters in the FDR caused by the (assumed) 1Hz sampling sequential, non-synchronous sampling if you try to draw conclusions from time stamps.
Not been in that situation, obviously, but I have certainly been in stressed situations where somewhere, someone (or something, or even me) pressed the wrong button, and I need to find out which one.
10 seconds is really not a long time if it is unexpected. It is very short.
Please also remember:
-We have no idea of exactly what was said. Whether the conversation referred to a error message, engines spooling down or physical switch movement/position. Throw in possible translation inaccuracies, and we can conclude even less from the information about the conversation, or what the level of clarity or confusion were.
Last edited by Kraftstoffvondesibel; 12th July 2025 at 23:09 .
July 13, 2025, 21:49:00 GMT
permalink Post: 11921703
A few observations
While IMO the Air India 171 preliminary report (
PR
) in some aspects leaves ample room for speculation rather than soothing it, let’s not loose sight of a straight forward assumption that what is presently known to AAIB India beyond what is explicitly stated in the
PR
, at least to AAIB India’s judgement (and I presume amongst others NTSB's as well), shouldn’t lead to any significantly different preliminary observations and conclusions than those made in the
PR
at this stage.
In other words, there shouldn't be at present other major known/established facts based on the EAFR readouts (2000+ parameters!), but for now not published, that could immediately lead to other observations/qualifications than those made in the present PR .
If there would be, this would actually mean the end of authority of air safety incident investigation and reporting around the globe as we have known it for the past decades.
In other words, there shouldn't be at present other major known/established facts based on the EAFR readouts (2000+ parameters!), but for now not published, that could immediately lead to other observations/qualifications than those made in the present PR .
If there would be, this would actually mean the end of authority of air safety incident investigation and reporting around the globe as we have known it for the past decades.
Last edited by D Bru; 13th July 2025 at 23:16 . Reason: finetuning of argument :)
July 14, 2025, 19:04:00 GMT
permalink Post: 11922436
Upfront: Sorry for my initial post on the topic, like some other people in this thread it obviously touches a nerve and was rightly removed for exceeding the rules of civil discussion.
This is my attempt to shed a bit of light on why I find pushing theories of suicide very objectionable at this point in time.
Let's actually run some numbers here.
https://www.boeing.com/content/dam/b...df/statsum.pdf gives us a nice statistic over the last 20 years and also has this little tidbit:
"965 million departures since 1959. 63% of those departures were on Boeing airplanes. (609 million on Boeing airplanes)"
For the last 20 years I'd eyeball an average of between 20-25 million departures per year. So 400-500 million flights in just 20 years. Maybe let that sink in for a moment. We have doubled the total number of flights in the 20 years since 2005.
In that timeframe we have:
Nov 2013, LAM 470, 33 fatalities, confirmed by CVR
Mar 2015, Germanwings 9525, 150 fatalities, confirmed by CVR
There are additionally these:
Mar 2014, MH370, 239 fatalities, no final report, no information available
Mar 2022, CES5735, 132 fatalities, no final report, media reports claiming pilot suicide, strong counter by the investigating agency: "CAAC has previously said speculation surrounding the crash had "gravely misled the public" and interfered with accident investigation work."
Both confirmed cases in that time have a very clear pattern that does in no way resemble the Air India Crash.
Even beyond that timeframe no confirmed pilot suicide involved any measures against discovery by the departed.
There is speculation regarding Silk Air 185 because the CVR failed to record the relevant part of the accident, but it is firmly in the "debated" category.
But we can ignore all of that. Even if we put any theoretically possible Pilot Suicide into the equation one fact remains: The actual likeliness of pilot suicide has not changed. There were 2 confirmed prior to 2005 and 2 after and 2 suspected prior to 2005 2 and after. And that is despite a higher sensitivity and a more stressful job as well as significantly increased environmental stress factors. Obviously we are talking about, statistically speaking, numbers too small for analysis, but all of this is actually well within expected parameters. The recent years have seen a focus on mental health in general in many countries worldwide, and mental healthcare availability is growing in most countries. And here the US is a great example as far as aviation goes: https://casten.house.gov/media/press...tion-committee With this bill whose merit can be assessed by the people supporting it: " The legislation is endorsed by the Pilot Mental Health Campaign, Air Line Pilots Association, Airlines for America, the National Air Traffic Controllers Association, National Flight Training Alliance, the National Business Aviation Association, and NetJets Association of Shared Aircraft Pilots (NJASAP)."
Summing up I would like to point out that there are good indications that there are no mental health issues involved here. Taking the aforementioned accidents as reference the issues were usually quite obvious once any kind of scrutiny was placed on the individuals involved. The individuals also made little to no effort of concealment in all confirmed cases and while the absence of evidence can be interpreted as indicative of successful concealment it is not proof and cannot be treated as such. Especially when it is documented that the overwhelming majority of suicides do not involve any element of concealment, and the psychological mechanisms at work commonly preclude any thought about what happens after, as far as medical study of the issue is concerned. This does not mean it does not happen, cases of concealment attempts or even partial successes are well documented, but it is a lot less prevalent. In this case estimates range mostly from between 10% to 30% of all suicides being misreported as unintentional injury with massive variation depending on multiple factors like country, ethnicity, gender, sexual identity, etc.
In final conclusion: Anyone can make mistakes. It is possible one or both of these pilots made a mistake. It is also possible that a combination of bad luck lead to an alignment of the holes. In my opinion the inability to receive urgently required medical support is as much a hole in the Swiss Cheese as the worst maintenance or design error imaginable. We know from the previous discussions in all threads on this Accident and the report itself that the pilots were flying their aircraft until they ran out of time and airspace. One cannot demand more from a human being, no matter what the final cause is ultimately determined to be.
This is my attempt to shed a bit of light on why I find pushing theories of suicide very objectionable at this point in time.
https://www.boeing.com/content/dam/b...df/statsum.pdf gives us a nice statistic over the last 20 years and also has this little tidbit:
"965 million departures since 1959. 63% of those departures were on Boeing airplanes. (609 million on Boeing airplanes)"
For the last 20 years I'd eyeball an average of between 20-25 million departures per year. So 400-500 million flights in just 20 years. Maybe let that sink in for a moment. We have doubled the total number of flights in the 20 years since 2005.
In that timeframe we have:
Nov 2013, LAM 470, 33 fatalities, confirmed by CVR
Mar 2015, Germanwings 9525, 150 fatalities, confirmed by CVR
There are additionally these:
Mar 2014, MH370, 239 fatalities, no final report, no information available
Mar 2022, CES5735, 132 fatalities, no final report, media reports claiming pilot suicide, strong counter by the investigating agency: "CAAC has previously said speculation surrounding the crash had "gravely misled the public" and interfered with accident investigation work."
Both confirmed cases in that time have a very clear pattern that does in no way resemble the Air India Crash.
Even beyond that timeframe no confirmed pilot suicide involved any measures against discovery by the departed.
There is speculation regarding Silk Air 185 because the CVR failed to record the relevant part of the accident, but it is firmly in the "debated" category.
But we can ignore all of that. Even if we put any theoretically possible Pilot Suicide into the equation one fact remains: The actual likeliness of pilot suicide has not changed. There were 2 confirmed prior to 2005 and 2 after and 2 suspected prior to 2005 2 and after. And that is despite a higher sensitivity and a more stressful job as well as significantly increased environmental stress factors. Obviously we are talking about, statistically speaking, numbers too small for analysis, but all of this is actually well within expected parameters. The recent years have seen a focus on mental health in general in many countries worldwide, and mental healthcare availability is growing in most countries. And here the US is a great example as far as aviation goes: https://casten.house.gov/media/press...tion-committee With this bill whose merit can be assessed by the people supporting it: " The legislation is endorsed by the Pilot Mental Health Campaign, Air Line Pilots Association, Airlines for America, the National Air Traffic Controllers Association, National Flight Training Alliance, the National Business Aviation Association, and NetJets Association of Shared Aircraft Pilots (NJASAP)."
Summing up I would like to point out that there are good indications that there are no mental health issues involved here. Taking the aforementioned accidents as reference the issues were usually quite obvious once any kind of scrutiny was placed on the individuals involved. The individuals also made little to no effort of concealment in all confirmed cases and while the absence of evidence can be interpreted as indicative of successful concealment it is not proof and cannot be treated as such. Especially when it is documented that the overwhelming majority of suicides do not involve any element of concealment, and the psychological mechanisms at work commonly preclude any thought about what happens after, as far as medical study of the issue is concerned. This does not mean it does not happen, cases of concealment attempts or even partial successes are well documented, but it is a lot less prevalent. In this case estimates range mostly from between 10% to 30% of all suicides being misreported as unintentional injury with massive variation depending on multiple factors like country, ethnicity, gender, sexual identity, etc.
In final conclusion: Anyone can make mistakes. It is possible one or both of these pilots made a mistake. It is also possible that a combination of bad luck lead to an alignment of the holes. In my opinion the inability to receive urgently required medical support is as much a hole in the Swiss Cheese as the worst maintenance or design error imaginable. We know from the previous discussions in all threads on this Accident and the report itself that the pilots were flying their aircraft until they ran out of time and airspace. One cannot demand more from a human being, no matter what the final cause is ultimately determined to be.
July 14, 2025, 19:47:00 GMT
permalink Post: 11922454
Upfront: Sorry for my initial post on the topic, like some other people in this thread it obviously touches a nerve and was rightly removed for exceeding the rules of civil discussion.
This is my attempt to shed a bit of light on why I find pushing theories of suicide very objectionable at this point in time.
Let's actually run some numbers here.
https://www.boeing.com/content/dam/b...df/statsum.pdf gives us a nice statistic over the last 20 years and also has this little tidbit:
"965 million departures since 1959. 63% of those departures were on Boeing airplanes. (609 million on Boeing airplanes)"
For the last 20 years I'd eyeball an average of between 20-25 million departures per year. So 400-500 million flights in just 20 years. Maybe let that sink in for a moment. We have doubled the total number of flights in the 20 years since 2005.
In that timeframe we have:
Nov 2013, LAM 470, 33 fatalities, confirmed by CVR
Mar 2015, Germanwings 9525, 150 fatalities, confirmed by CVR
There are additionally these:
Mar 2014, MH370, 239 fatalities, no final report, no information available
Mar 2022, CES5735, 132 fatalities, no final report, media reports claiming pilot suicide, strong counter by the investigating agency: "CAAC has previously said speculation surrounding the crash had "gravely misled the public" and interfered with accident investigation work."
Both confirmed cases in that time have a very clear pattern that does in no way resemble the Air India Crash.
Even beyond that timeframe no confirmed pilot suicide involved any measures against discovery by the departed.
There is speculation regarding Silk Air 185 because the CVR failed to record the relevant part of the accident, but it is firmly in the "debated" category.
But we can ignore all of that. Even if we put any theoretically possible Pilot Suicide into the equation one fact remains: The actual likeliness of pilot suicide has not changed. There were 2 confirmed prior to 2005 and 2 after and 2 suspected prior to 2005 2 and after. And that is despite a higher sensitivity and a more stressful job as well as significantly increased environmental stress factors. Obviously we are talking about, statistically speaking, numbers too small for analysis, but all of this is actually well within expected parameters. The recent years have seen a focus on mental health in general in many countries worldwide, and mental healthcare availability is growing in most countries. And here the US is a great example as far as aviation goes: https://casten.house.gov/media/press...tion-committee With this bill whose merit can be assessed by the people supporting it: " The legislation is endorsed by the Pilot Mental Health Campaign, Air Line Pilots Association, Airlines for America, the National Air Traffic Controllers Association, National Flight Training Alliance, the National Business Aviation Association, and NetJets Association of Shared Aircraft Pilots (NJASAP)."
Summing up I would like to point out that there are good indications that there are no mental health issues involved here. Taking the aforementioned accidents as reference the issues were usually quite obvious once any kind of scrutiny was placed on the individuals involved. The individuals also made little to no effort of concealment in all confirmed cases and while the absence of evidence can be interpreted as indicative of successful concealment it is not proof and cannot be treated as such. Especially when it is documented that the overwhelming majority of suicides do not involve any element of concealment, and the psychological mechanisms at work commonly preclude any thought about what happens after, as far as medical study of the issue is concerned. This does not mean it does not happen, cases of concealment attempts or even partial successes are well documented, but it is a lot less prevalent. In this case estimates range mostly from between 10% to 30% of all suicides being misreported as unintentional injury with massive variation depending on multiple factors like country, ethnicity, gender, sexual identity, etc.
In final conclusion: Anyone can make mistakes. It is possible one or both of these pilots made a mistake. It is also possible that a combination of bad luck lead to an alignment of the holes. In my opinion the inability to receive urgently required medical support is as much a hole in the Swiss Cheese as the worst maintenance or design error imaginable. We know from the previous discussions in all threads on this Accident and the report itself that the pilots were flying their aircraft until they ran out of time and airspace. One cannot demand more from a human being, no matter what the final cause is ultimately determined to be.
This is my attempt to shed a bit of light on why I find pushing theories of suicide very objectionable at this point in time.
Let's actually run some numbers here.
https://www.boeing.com/content/dam/b...df/statsum.pdf gives us a nice statistic over the last 20 years and also has this little tidbit:
"965 million departures since 1959. 63% of those departures were on Boeing airplanes. (609 million on Boeing airplanes)"
For the last 20 years I'd eyeball an average of between 20-25 million departures per year. So 400-500 million flights in just 20 years. Maybe let that sink in for a moment. We have doubled the total number of flights in the 20 years since 2005.
In that timeframe we have:
Nov 2013, LAM 470, 33 fatalities, confirmed by CVR
Mar 2015, Germanwings 9525, 150 fatalities, confirmed by CVR
There are additionally these:
Mar 2014, MH370, 239 fatalities, no final report, no information available
Mar 2022, CES5735, 132 fatalities, no final report, media reports claiming pilot suicide, strong counter by the investigating agency: "CAAC has previously said speculation surrounding the crash had "gravely misled the public" and interfered with accident investigation work."
Both confirmed cases in that time have a very clear pattern that does in no way resemble the Air India Crash.
Even beyond that timeframe no confirmed pilot suicide involved any measures against discovery by the departed.
There is speculation regarding Silk Air 185 because the CVR failed to record the relevant part of the accident, but it is firmly in the "debated" category.
But we can ignore all of that. Even if we put any theoretically possible Pilot Suicide into the equation one fact remains: The actual likeliness of pilot suicide has not changed. There were 2 confirmed prior to 2005 and 2 after and 2 suspected prior to 2005 2 and after. And that is despite a higher sensitivity and a more stressful job as well as significantly increased environmental stress factors. Obviously we are talking about, statistically speaking, numbers too small for analysis, but all of this is actually well within expected parameters. The recent years have seen a focus on mental health in general in many countries worldwide, and mental healthcare availability is growing in most countries. And here the US is a great example as far as aviation goes: https://casten.house.gov/media/press...tion-committee With this bill whose merit can be assessed by the people supporting it: " The legislation is endorsed by the Pilot Mental Health Campaign, Air Line Pilots Association, Airlines for America, the National Air Traffic Controllers Association, National Flight Training Alliance, the National Business Aviation Association, and NetJets Association of Shared Aircraft Pilots (NJASAP)."
Summing up I would like to point out that there are good indications that there are no mental health issues involved here. Taking the aforementioned accidents as reference the issues were usually quite obvious once any kind of scrutiny was placed on the individuals involved. The individuals also made little to no effort of concealment in all confirmed cases and while the absence of evidence can be interpreted as indicative of successful concealment it is not proof and cannot be treated as such. Especially when it is documented that the overwhelming majority of suicides do not involve any element of concealment, and the psychological mechanisms at work commonly preclude any thought about what happens after, as far as medical study of the issue is concerned. This does not mean it does not happen, cases of concealment attempts or even partial successes are well documented, but it is a lot less prevalent. In this case estimates range mostly from between 10% to 30% of all suicides being misreported as unintentional injury with massive variation depending on multiple factors like country, ethnicity, gender, sexual identity, etc.
In final conclusion: Anyone can make mistakes. It is possible one or both of these pilots made a mistake. It is also possible that a combination of bad luck lead to an alignment of the holes. In my opinion the inability to receive urgently required medical support is as much a hole in the Swiss Cheese as the worst maintenance or design error imaginable. We know from the previous discussions in all threads on this Accident and the report itself that the pilots were flying their aircraft until they ran out of time and airspace. One cannot demand more from a human being, no matter what the final cause is ultimately determined to be.
ANY Boeing pilot who grabs for the FCSs immediately after takeoff has SOME type of mental health issue. It might be suicidal, it might be cognitive, it might be a stroke, it might be some type of blood interruption to the brain, chemical imbalance, drug reaction, or whatever.
It’s not a simple mistake.
I’m not saying it’s necessary deliberate or homicidal (which it could be) but there is some type of impairment there. Everyone knows the consequences of shutting off a FCS or pulling a fire handle. The switches aren’t easily confused with others. Bumping them doesn’t cause them to go to cut off. And have dire consequences if actuated at the wrong time.
I guess there might theoretically be a way to snag them with loose clothing (like having a very frayed sweater with holes in the sleeve putting one’s arm in a really strange place) somehow and while pulling to free it manage to pull them out and down but I’m going to put this in the asteroid hitting earth category.
July 14, 2025, 19:53:00 GMT
permalink Post: 11922462
I find it hard to believe that, in this instance, there is anything inherently wrong in the aircraft or its associated powerplants. The report appears to indicate that all the correct parameters had been met with regard to W&B and performance planning whilst the aircraft was performing normally until just after rotate.
The apparent lack of information with regard to the CVR transcript appears to be telling. If the F/O was handling pilot using a mixture of visual references and the HUD, one wonders what he would have seen or sensed to make him ask the question ‘why did you do that ?’ when it became apparent through Eicas or simple loss of thrust that the engines had shut down - his remark is very specific and not perhaps the normal expletive ridden response that one might expect.
Again, here, I am making as assumption that the initial remark was made by the FO because the report does not tell us who said what. Whilst it may be easy to jump on the bandwagon of the deliberate and premeditated act I would still give some credence to the idea that the fuel control switches were actioned in a completely erroneous act if for no other reason that I have seen similar faux pas in the simulator on multiple occasions.
There may of course be a cultural issue in play here with the relationship between the two pilots which has been seen in many previous accidents/incidents. Equally the strange timing of the releasing of the report potentially raises a question or two though maybe that is a conspiracy theory too far !
The apparent lack of information with regard to the CVR transcript appears to be telling. If the F/O was handling pilot using a mixture of visual references and the HUD, one wonders what he would have seen or sensed to make him ask the question ‘why did you do that ?’ when it became apparent through Eicas or simple loss of thrust that the engines had shut down - his remark is very specific and not perhaps the normal expletive ridden response that one might expect.
Again, here, I am making as assumption that the initial remark was made by the FO because the report does not tell us who said what. Whilst it may be easy to jump on the bandwagon of the deliberate and premeditated act I would still give some credence to the idea that the fuel control switches were actioned in a completely erroneous act if for no other reason that I have seen similar faux pas in the simulator on multiple occasions.
There may of course be a cultural issue in play here with the relationship between the two pilots which has been seen in many previous accidents/incidents. Equally the strange timing of the releasing of the report potentially raises a question or two though maybe that is a conspiracy theory too far !
July 14, 2025, 20:32:00 GMT
permalink Post: 11922481
Again, not familiar with the specifics of the 787, but on the 747-400/-8, one pole of the fuel switch feeds EICAS - which uses it in various message logic - and sends it out to any other aircraft systems that use it. There is "Digital Flight Data Acquisition Unit) DFDAU (pronounced Daff Du) that takes all the various system digital signals, sorts them and provides them to the DFDR and QAR. The 787 has something similar to the DFDAU but I don't recall what it's called.
The EAFRs simply sniff the required data from the CDN, so there's no DFDAU as such.
For some parameters, including the fuel cutoff switches, the EAFRs also record a "Source Index." For the fuel cutoff switches, there are 4 sources numbered 1 through 4 as well as a valid/invalid flag. I don't know what the sources are, but perhaps they're the 2 RDCs plus the 2 channels of the EEC/FADEC. It appears that source 1 (the default) is not the EEC.