June 13, 2025, 22:59:00 GMT
permalink Post: 11900982
Speaking as a B787 Captain..... There is so much rubbish and stupid suggestion being written here.
This aircraft was airborne for a grand total of 22 seconds, half of which was climbing to no more than 150' aal.
- No Flaps? Due to the setup of the ECL it is physically impossible to go down the runway without some sort of take-off flap set. The T/o config warning would have been singing it's head off. Despite assertions to the contrary I have seen no video clear enough to detect a lack of flaps.
- RAT out? Almost impossible, I have seen no quality footage that definitively witnesses the RAT being out. Those who think they car hear a RAT type noise might be listening to a motorcycle passing or similar. It takes a triple hydraulic failure or a double engine failure to trigger RAT deploment. They happily went through V1 without a hint of rejected take off so as they rotated the aircraft was serviceable. These are big engines, they take a long time to wind down when you shut them down. I have never tried it however engine failure detection takes 30s or for the aircraft to react and they were not even airborne that long.
- Flaps up instead of gear? The B787 flaps are slow both in and out. Given that the 'Positive rate' call is not made the second the wheels leave the ground, a mis-selection of flaps up would not cause any loss of lift for at least 20 seconds, by which time they had already crashed. I believe the gear remained down not because of mis-selection but because of a major distraction on rotate.
Discounting the impossible, two hypotheses remain:
1. Invalid derate set through incorrect cross-checking. Trundling down the runway takes very little power to reach Vr. It is only when you rotate that you create more drag and discover that you do not have sufficient thrust vs. drag to sustain a climb. Or....
2. Put 200' as the altitude target in the FCU. Immediate ALT capture and all the power comes off. PF is still hand flying trying to increase pitch but is already way behind the aircraft.
It could be after this that Boeing are forced to review the B787 practice of exploring the very edges of the performance envelope.
This aircraft was airborne for a grand total of 22 seconds, half of which was climbing to no more than 150' aal.
- No Flaps? Due to the setup of the ECL it is physically impossible to go down the runway without some sort of take-off flap set. The T/o config warning would have been singing it's head off. Despite assertions to the contrary I have seen no video clear enough to detect a lack of flaps.
- RAT out? Almost impossible, I have seen no quality footage that definitively witnesses the RAT being out. Those who think they car hear a RAT type noise might be listening to a motorcycle passing or similar. It takes a triple hydraulic failure or a double engine failure to trigger RAT deploment. They happily went through V1 without a hint of rejected take off so as they rotated the aircraft was serviceable. These are big engines, they take a long time to wind down when you shut them down. I have never tried it however engine failure detection takes 30s or for the aircraft to react and they were not even airborne that long.
- Flaps up instead of gear? The B787 flaps are slow both in and out. Given that the 'Positive rate' call is not made the second the wheels leave the ground, a mis-selection of flaps up would not cause any loss of lift for at least 20 seconds, by which time they had already crashed. I believe the gear remained down not because of mis-selection but because of a major distraction on rotate.
Discounting the impossible, two hypotheses remain:
1. Invalid derate set through incorrect cross-checking. Trundling down the runway takes very little power to reach Vr. It is only when you rotate that you create more drag and discover that you do not have sufficient thrust vs. drag to sustain a climb. Or....
2. Put 200' as the altitude target in the FCU. Immediate ALT capture and all the power comes off. PF is still hand flying trying to increase pitch but is already way behind the aircraft.
It could be after this that Boeing are forced to review the B787 practice of exploring the very edges of the performance envelope.
The engines, however: yes they take a long time to wind down fully , but they don't take long to stop providing thrust if you shut them down or cut the fuel (or indeed have a bird strike). I don't understand why you consider a loss of thrust to be an impossible hypothesis.
There's also a still image above which appears to show a deployed RAT; that's even if we discount the sound track, which might indeed be something else than a RAT, and ignore the sound of the crash being clearly audible despite the lack of engine noise earlier in the video.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Dual Engine Failure Engine Failure (All) Engine Failure Detection Time Hydraulic Failure (All) RAT (All) RAT (Deployment) V1
June 14, 2025, 13:32:00 GMT
permalink Post: 11901486
My understanding is that RATs have variable-pitch props, so the RPM wouldn't be strongly linked to airspeed.
Subjects: None
June 14, 2025, 15:06:00 GMT
permalink Post: 11901555
- The bogie could be explained by the Flap/Slat priority valve giving priority to the flaps if the PM suddenly realised his mistake and quickly put the flap lever back to the TO position and then selected the gear lever to UP. Those systems are both heavy hitters and would’ve sucked the life out of the CTR hydraulic system pumps.
- There is no way loss of AC (alleged RAT deployment) could've caused a spool down of both engines. Think QF A380 incident in SIN - The entire #1 engine wiring harness in the wing was completely severed and yet it continued (by design) to run at its previous thrust setting. They had to shut it down using a fire truck!
- History and design would dictate that a big 180 minutes ETOP’s twin such as the 787 having a dual engine failure or significant power loss at such a critical phase of flight would be a billion to one chance at best. Only the Airbus A400 had a software issue causing all 4 engine fuel shutoff valves to close causing it to crash killing the flight test crew - But this was during its development and flt testing.
- Wide body twin’s delivering in the region of 60,000 to 115,000 lbs of thrust at TO rarely , if at all, flame out from multiple bird strike(s) like the baby Bus’s and Boeing’s. If anyone has seen the frozen chickens at TO power video would know what I’m talking about. And the Fan Blade being ‘blown off’ as well. In both cases the engine was was able to maintain full TOGA thrust for significantly longer than the AI aircraft.
- There is no way loss of AC (alleged RAT deployment) could've caused a spool down of both engines. Think QF A380 incident in SIN - The entire #1 engine wiring harness in the wing was completely severed and yet it continued (by design) to run at its previous thrust setting. They had to shut it down using a fire truck!
- History and design would dictate that a big 180 minutes ETOP’s twin such as the 787 having a dual engine failure or significant power loss at such a critical phase of flight would be a billion to one chance at best. Only the Airbus A400 had a software issue causing all 4 engine fuel shutoff valves to close causing it to crash killing the flight test crew - But this was during its development and flt testing.
- Wide body twin’s delivering in the region of 60,000 to 115,000 lbs of thrust at TO rarely , if at all, flame out from multiple bird strike(s) like the baby Bus’s and Boeing’s. If anyone has seen the frozen chickens at TO power video would know what I’m talking about. And the Fan Blade being ‘blown off’ as well. In both cases the engine was was able to maintain full TOGA thrust for significantly longer than the AI aircraft.
As for history and design making a dual-engine failure a billion to one chance: I'd be more inclined to agree that it's unlikely to be what happened if the actual manufacturing of planes (Boeings in particular) and the maintenance procedures were both carried out "by the book" at all times by the manufacturer and the airlines... This is clearly not the case though.
Last edited by Saab Dastard; 14th June 2025 at 19:35 . Reason: reference to deleted posts removed
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Dual Engine Failure Engine Failure (All) Gear Lever Hydraulic Failure (All) RAT (All) RAT (Deployment) TOGA
June 14, 2025, 16:04:00 GMT
permalink Post: 11901609
I believe the point being made by the person you quoted was that the noise of the engines might have become much quieter
before
the start of the video with the possible RAT noise (the one where the plane passes almost overhead).
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) RAT (All)
June 14, 2025, 22:19:00 GMT
permalink Post: 11901899
I'm still sticking with "Major Electrical Fault" as my most likely cause, and this adds to my suspicions.
[snip]
Anyway, there MUST be ways that the redundant power supplies can be brought down, simply because, to have a critical bus powered from a number of independent sources, there must be "controls" of some sort. I don't know how it's done in the 787, but that's where I'd be looking.
As there is a lot of discussion already about how the bogies are hanging the wrong way suggesting a started but failed retraction operation, and it's now confirmed that the retraction would normally have taken place at about the point where the flight went "pear shaped", I'm going to suggest that the two things are connected. More than that: I'll suggest that the Gear Up command triggered the fault that caused both engines to shut down in very short succession. Nothing the pilots did wrong, and no way they could have known and prevented it.
[snip]
Anyway, there MUST be ways that the redundant power supplies can be brought down, simply because, to have a critical bus powered from a number of independent sources, there must be "controls" of some sort. I don't know how it's done in the 787, but that's where I'd be looking.
As there is a lot of discussion already about how the bogies are hanging the wrong way suggesting a started but failed retraction operation, and it's now confirmed that the retraction would normally have taken place at about the point where the flight went "pear shaped", I'm going to suggest that the two things are connected. More than that: I'll suggest that the Gear Up command triggered the fault that caused both engines to shut down in very short succession. Nothing the pilots did wrong, and no way they could have known and prevented it.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Electrical Failure Fuel (All)
June 14, 2025, 22:29:00 GMT
permalink Post: 11901908
You mean if #2 failed (fire?) and the fire handle was pulled for #1? Then yes for sure that'd leave the plane without thrust but (a) that seems totally unconnected to the electrical failure hypothesis under discussion and (b) seems likely to have produced some visible "smoke" trails from the engines (not seen on video).
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Electrical Failure
June 14, 2025, 22:43:00 GMT
permalink Post: 11901915
I've seen nothing to confirm if or when the engines stopped providing thrust, but if you assume that it happened and that it came after the wheels left the ground then you'd also have to assume there was a pretty serious design flaw in the WOW system for it to falsely indicate weight on the wheels just because there was an issue raising the gear. It feels like kinda the same thing as assuming a serious flaw in the overall TCMA system.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Weight on Wheels
June 15, 2025, 19:03:00 GMT
permalink Post: 11902726
I'd phrase it differently: the frequency (and harmonics) of the noise are consistent with it being a RAT. If you then assume that it was a RAT and infer distance and speed curves from the Doppler variation, you get plausible values for an aircraft. But the two things are somewhat linked so you can't really treat the second thing as confirmation of the first. (FWIW, I'm personally quite satisfied that it was indeed a RAT on the audio.)
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Dual Engine Failure Engine Failure (All) FDR RAT (All) RAT (Deployment)
July 12, 2025, 18:11:00 GMT
permalink Post: 11920724
(First, I've read the whole thread, and most of the content in the previous threads, though they are obviously of less relevance in some areas now.)
This notion has caused me some concern, since seeing at least one very similar remark when I read the other threads (possibly by the same poster, though?).
It seems extremely undesirable for TCs to end up habituated to taking actions like this without thought. I wonder if it creates a case for the sim setups being performed by non-flying personnel?
Meanwhile, I read the prelim report. The English is generally fairly good but I note multiple mistakes/typos, and some oddities. One such oddity is that the timestamp of the second cutoff switch change isn't listed explicitly anywhere I can find, but instead just a relative time: "gap of 01 second". To write "1" as "01" like this invites speculation that it's a typo for 0.1; this is unlikely, given the polling frequency mentioned by some posts above, but nonetheless seems odd. (I am aware that Indian conventions differ from those in US/UK English, including placement of commas in large numbers, but I don't think this is such a case.)
Another indication to suggest it hasn't been proof-read very effectively: the FADEC is also described as a "... Dual ..." instead of "... Digital ...".
Every sim the TC has conducted he will have moved critical switches without much thought in order to setup the sim for the exercise. I remember being slightly shocked one day on the aircraft, having been training in the sim the previous day, that I nearly operated a critical control without thought. It\x92s something I had to consciously guard against after that.
It seems extremely undesirable for TCs to end up habituated to taking actions like this without thought. I wonder if it creates a case for the sim setups being performed by non-flying personnel?
Meanwhile, I read the prelim report. The English is generally fairly good but I note multiple mistakes/typos, and some oddities. One such oddity is that the timestamp of the second cutoff switch change isn't listed explicitly anywhere I can find, but instead just a relative time: "gap of 01 second". To write "1" as "01" like this invites speculation that it's a typo for 0.1; this is unlikely, given the polling frequency mentioned by some posts above, but nonetheless seems odd. (I am aware that Indian conventions differ from those in US/UK English, including placement of commas in large numbers, but I don't think this is such a case.)
Another indication to suggest it hasn't been proof-read very effectively: the FADEC is also described as a "... Dual ..." instead of "... Digital ...".
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FADEC Fuel (All) Fuel Cutoff Switches Preliminary Report Switch Guards
July 12, 2025, 20:18:00 GMT
permalink Post: 11920807
as per the report- at *most* 1s apart, particularly significant given that it has been mentioned the recording interval of the DFDR is 1s
also I don\x92t know if we\x92ve had an adequate answer to the fact of what data streams the DFDR records, was it only detecting the electrical signal of fuel cut off or the actual position of the toggles- I don\x92t believe it would be the latter which opens an entirely different rabbit hole
also I don\x92t know if we\x92ve had an adequate answer to the fact of what data streams the DFDR records, was it only detecting the electrical signal of fuel cut off or the actual position of the toggles- I don\x92t believe it would be the latter which opens an entirely different rabbit hole
Regarding your second point: it has been noted by multiple posters that "the actual position" of the switch is a fairly meaningless concept for the EAFR data if you want to exclude the electrical signal arising from the switch itself. So I have to ask: what would you regard as a measurement of the "actual position of the switch", in this context?
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): DFDR EAFR Fuel (All) Fuel Cutoff Fuel Cutoff Switches
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.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) Fuel Cutoff Switches Pilot "Why did you cut off" Preliminary Report
July 12, 2025, 23:39:00 GMT
permalink Post: 11920931
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All) Fuel Cutoff Switches Thread Moderation
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
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): CVR Fuel (All) Fuel Cutoff Switches Pilot "Why did you cut off" Preliminary Report Timeline (Preliminary Report) V1
July 13, 2025, 13:53:00 GMT
permalink Post: 11921338
In answer to those asking "why can't we talk about suicide?", the simple answer is because the mods have repeatedly asked that posts take this approach:
Most people don't think it's unavoidable, with the information available right now. For sure, the dogs in the street have known
since day 1
that it's
possible
, but unavoidable? No.
As we are a pilot's forum, I think we owe it to our group to not
promote
a discussion about suicide until/unless it is unavoidable based upon factual reporting.
Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Thread Moderation
July 13, 2025, 14:31:00 GMT
permalink Post: 11921358
Subjects: None