June 13, 2025, 23:43:00 GMT
permalink Post: 11901006
June 13, 2025, 23:49:00 GMT
permalink Post: 11901007
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.
Even though these are big engines with plenty of inertia, when you select engine shut off they spool down very quickly if on load. IE, The generators, two per engine and hydraulic pumps, etc, being driven by the (relatively) small mass of the N2 rotor will drag the speed down very quickly, the gennies will trip offine in seconds, the pumps will quickly reduce flow and pressure.
As for what went wrong.
If the engines have stopped working there has to be a common failure mode, fuel is one but as has been said, no other aircraft has had a problem, as far as we know. FOD? It would have to be something major to shut down two GeNX engines and there would be debris all over the runway, we would know by now.
I have no idea if the RAT has deployed, I can't see it in the video and the noise could be something else.
We shall see.
There is compelling evidence that flaps are set correctly and not retracted inadvertently.
I await further evidence.
Edit to add. LAE 40 years, type rated on 737 to 787 with lots of others in between.
June 13, 2025, 23:51:00 GMT
permalink Post: 11901008
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 ALT capture is what caught EK\x92s 777 out in DBX right? I still can\x92t think of a logical reason why they continued to allow ALT capture below thrust reduction height (depending on your operator 400-1000 AGL), that seems like a latent threat.
June 13, 2025, 23:58:00 GMT
permalink Post: 11901012
The B787 is a way way different and much more complex and sophisticated plane than your Gulfie. The B787's two outermost (left & right) hydraulic systems are primarily driven by the engines, mechanically driving the hydraulic pumps. The center hydraulics are primarily electrically driven, and power the main flight controls, amongst other things like the gear. The left and right ones power the main flight controls as well, some of the less important flight control surfaces like spoilers and thrust reversers -- pardon me for not having the exact list of things. They also have a backup/supplementary electric pump each. Each of the two main engines has redundancy for the power plant a.k.a. VFSG (and motor-driven pump?) in its own right as well. All three hydraulic systems work together in a redundant fashion when it comes to the primary flight controls. The RAT can provide both electrical and mechanical sources of hydraulic support, if I'm not mistaken. The flight instrument and information systems can also be powered from two backup batteries, the APU power plant itself, and/or the RAT.
June 14, 2025, 00:00:00 GMT
permalink Post: 11901015
June 14, 2025, 00:01:00 GMT
permalink Post: 11901016
Right, that's because it's not not meant to be used during normal flight operations. Generally, usage of the RAT indicates #### has hit the fan(blades).
To corroborate this, one can note that the RAT cannot be stowed once it's deployed under these conditions. That's because the RAT is ultimately either deployed because it's "forced" out by an active signal, OR it's deployed because the electromagnetic system is de-energized and the spring loaded mount flaps it out. That's what happens when nothing is stopping the spring from doing spring action things, like you'd see when there's no power going to whatever usually holds it shut.
To corroborate this, one can note that the RAT cannot be stowed once it's deployed under these conditions. That's because the RAT is ultimately either deployed because it's "forced" out by an active signal, OR it's deployed because the electromagnetic system is de-energized and the spring loaded mount flaps it out. That's what happens when nothing is stopping the spring from doing spring action things, like you'd see when there's no power going to whatever usually holds it shut.
June 14, 2025, 00:22:00 GMT
permalink Post: 11901021
The B787 is a way way different and much more complex and sophisticated plane than your Gulfie. The B787's two outermost (left & right) hydraulic systems are primarily driven by the engines, mechanically driving the hydraulic pumps. The center hydraulics are primarily electrically driven, and power the main flight controls. The left and right ones power the main flight controls as well, some of the less important flight control surfaces like spoilers and thrust reversers -- pardon me for not having the exact list of things. They also have a backup/supplementary electric pump each. Each of the two main engines has redundancy for the power plant a.k.a. VFSG (and motor-driven pump?) in its own right as well. All three hydraulic systems work together in a redundant fashion when it comes to the primary flight controls. The RAT can provide both electrical and mechanical sources of hydraulic support, if I'm not mistaken. The flight instrument and information systems can also be powered from two backup batteries, the APU power plant itself, and/or the RAT.
June 14, 2025, 00:23:00 GMT
permalink Post: 11901022
RAT out? I think not. Sounds like aorflow changes as flaps retracted.
Flap lever quadrant has a gate preventing quick lever movement past F1 position.
So if flap lever selected on first movement, the lever goes to F1 position, where only the trailing edge flaps retracted whereas the slats remained at takeoff setting.
Hoping against hope it wasn’t a brain fart!😖
Flap lever quadrant has a gate preventing quick lever movement past F1 position.
So if flap lever selected on first movement, the lever goes to F1 position, where only the trailing edge flaps retracted whereas the slats remained at takeoff setting.
Hoping against hope it wasn’t a brain fart!😖
June 14, 2025, 00:34:00 GMT
permalink Post: 11901030
RAT out? I think not. Sounds like aorflow changes as flaps retracted.
Flap lever quadrant has a gate preventing quick lever movement past F1 position.
So if flap lever selected on first movement, the lever goes to F1 position, where only the trailing edge flaps retracted whereas the slats remained at takeoff setting.
Hoping against hope it wasn\x92t a brain fart!😖
Flap lever quadrant has a gate preventing quick lever movement past F1 position.
So if flap lever selected on first movement, the lever goes to F1 position, where only the trailing edge flaps retracted whereas the slats remained at takeoff setting.
Hoping against hope it wasn\x92t a brain fart!😖
June 14, 2025, 01:03:00 GMT
permalink Post: 11901050
That's because the RAT is ultimately either deployed because it's "forced" out by an active signal, OR it's deployed because the electromagnetic system is de-energized and the spring loaded mount flaps it out. That's what happens when nothing is stopping the spring from doing spring action things, like you'd see when there's no power going to whatever usually holds it shut.
June 14, 2025, 01:37:00 GMT
permalink Post: 11901066
AD validity
Still valid Dave. That AD was raised circa post #248 (Search thread for \x93AD\x94)
All four Variable Frequency Generators (2 per engine) going offline at once is too much of a coincidence not to mention that AD.
RAT deployment has been substantiated, which occurs automatically, extension of which takes about 6 secs & would be heard by pax in the cabin as a loud \x93bang\x94 as the leg locks into place.
The sole on-board survivor quote regarding flickering green/white lights (Emergency Exit lights) directly adjacent to his seat 11A, speaks to electrical disruption during the takeoff phase.
If the double engine failure or electrical bus/distribution failure causing loss of thrust occurred for a reason other than the AD mentioned above, the cause will need to be established without delay lest the void is filled with mis-information, fear, uncertainty, & doubt.
The current level of trust in the manufacturer is fragile for good reason.
.
This occurrence will have operators & regulators around the world reviewing their risk assessment models, especially regarding Master Minimum Equipment List (MMEL)/ Defect Deferral Guide (DDG) maintenance relief.
Compliance & maintenance come at a cost.
Lack thereof comes at a far greater & heavier cost.
All four Variable Frequency Generators (2 per engine) going offline at once is too much of a coincidence not to mention that AD.
RAT deployment has been substantiated, which occurs automatically, extension of which takes about 6 secs & would be heard by pax in the cabin as a loud \x93bang\x94 as the leg locks into place.
The sole on-board survivor quote regarding flickering green/white lights (Emergency Exit lights) directly adjacent to his seat 11A, speaks to electrical disruption during the takeoff phase.
If the double engine failure or electrical bus/distribution failure causing loss of thrust occurred for a reason other than the AD mentioned above, the cause will need to be established without delay lest the void is filled with mis-information, fear, uncertainty, & doubt.
The current level of trust in the manufacturer is fragile for good reason.
.
This occurrence will have operators & regulators around the world reviewing their risk assessment models, especially regarding Master Minimum Equipment List (MMEL)/ Defect Deferral Guide (DDG) maintenance relief.
Compliance & maintenance come at a cost.
Lack thereof comes at a far greater & heavier cost.
June 14, 2025, 01:48:00 GMT
permalink Post: 11901070
Right, that's because it's not not meant to be used during normal flight operations. Generally, usage of the RAT indicates #### has hit the fan(blades).
To corroborate this, one can note that the RAT cannot be stowed once it's deployed under these conditions. That's because the RAT is ultimately either deployed because it's "forced" out by an active signal, OR it's deployed because the electromagnetic system is de-energized and the spring loaded mount flaps it out. That's what happens when nothing is stopping the spring from doing spring action things, like you'd see when there's no power going to whatever usually holds it shut.
To corroborate this, one can note that the RAT cannot be stowed once it's deployed under these conditions. That's because the RAT is ultimately either deployed because it's "forced" out by an active signal, OR it's deployed because the electromagnetic system is de-energized and the spring loaded mount flaps it out. That's what happens when nothing is stopping the spring from doing spring action things, like you'd see when there's no power going to whatever usually holds it shut.
On the ground, the switch was in RET, then placed in AUTO on the taxi-out. About once a year and new pilot in the left seat would drop by going thru AITO to DEPLOY. Oops, “just go up to RET, then AUTO, this time.
June 14, 2025, 02:16:00 GMT
permalink Post: 11901080
As many will know, on the Boeing 787-8,
each main gear door is hydraulically actuated and powered by its respective side’s hydraulic system
— the
left gear door by the left hydraulic system
, and the
right by the right
. This leads me to propose the following hypothesis:
The Centre Hydraulic system is powered by two Electric Motor Pumps.
Obviously, the two Centre pumps are ultimately powered by electrical power from the VFSGs on the engines and/or the APU.
Note: the RAT will not (and could not!) supply hydraulic power to the gear system.
June 14, 2025, 02:39:00 GMT
permalink Post: 11901091
Are you thinking of the EK A340 that departed with a 100 ton descepancy entered in the box resulting in incorrect thrust derate and under cooked V speeds? That aircraft was saved by the flight crew that fire walled the thrust leavers with about 600M remaining. Tail strike and destroyed the LOC antenta, but was able to get Airbourne then return for landing at YMML. Is this a possibility? 100 ton gross error, resulting in incorrect thrust, speeds and flap setting? Pilot mistakes lack of thrust for partial engine failure? The confusion and startle factor as the aircraft is rotating with a surprising lack of thrust and the runway end fast approaching may account for the gear not being selected up. If there were a gross error in the weight entered in the FMC, no takeoff config warning. 40 degrees C, flaps 5 instead of flaps 15 or similar? Hopefully some initial data from the FDR may be a pretty good indication.
If RAT out ??? That tells a lot .
Not long to wait now ?
condolences to family\x92s and loved ones !
Last edited by Toruk Macto; 14th June 2025 at 04:30 .
June 14, 2025, 02:51:00 GMT
permalink Post: 11901095
I attempted a rudimentary timeline analysis of the two most prominent videos. Folks on here are usually far quicker & more adept than me at producing this type of analysis, so approach the following with due scepticism!
Please verify the videos using the links below, so we know we are all talking about the same thing. I deliberately avoid any judgment regarding theories posted thus far - I am merely supplying information against which you can further test those theories.
1. Primary eye witness video with audio:
[ X link ending 1933089931347345596 in case the hyperlink itself doesn't work for any reason]
- Footage starts with aircraft directly overhead, give or take, (based on both sound & vision)
- 13 seconds from start until fireball clearly visible above roofline
2. Airport CCTV:
[X link ending 1933162059556159903 ]
- 49-50 seconds until impact and fireball clearly visible
Subtract the 13 secs noted in video #1 and this establishes the approximate moment the aircraft passes over the video witness's position when viewed from video #2 (CCTV):
49 - 13 = 36 secs into video 2
Estimated timeline (CCTV #2):
19s: rotate
31s: climb rate noticeably deteriorates (12s after TO / 18s from impact)
36s: estimated moment aircraft overflies eyewitness camera (17s after TO / 13s from impact)
38-40s: pitch up then descent begins (19-21s from TO / 9-11s from impact)
49s: first contact with ground (30s after TO / approx impact)
50s: fireball visible above rooftops
Conclusions from combining both videos:
- Aircraft overflies eyewitness camera roughly 13 secs before impact
- This is well after it has stopped climbing (~6 secs)
- This is also mere seconds before CCTV shows the aircraft pitch up and start to descend (which I believe I can substantiate in the eye witness video, although this is tougher to confirm with the naked eye from this viewing angle - someone may have to look more closely than I can this evening!)
- I have previously asked questions about the audio in video #1 and whether we can draw any conclusions regarding RAT deployment & engine thrust. There are strong opinions on both sides. Your personal view on this will influence your evaluation of what the videos show, but either way your theory needs to fit the timeline (or advance a different one).
So, anyone who is developing a theory ought to consider whether it is consistent with the following:-
- rate of climb decays to 0ft/m within 10-12 secs of rotation
- RAT (possibly) audible within 17s of rotation *
- pitch up shortly afterwards with no discernible increase in engine noise & unable to arrest descent
- impact with ground within 30 secs of rotation
* I recognise that the RAT deployment is not an established fact, but any theory that proposes RAT deployment needs to take into account this timeline in addition to the rest.
Alternatively, you are welcome to refute this simplistic, late night analysis of the limited video evidence.
Please verify the videos using the links below, so we know we are all talking about the same thing. I deliberately avoid any judgment regarding theories posted thus far - I am merely supplying information against which you can further test those theories.
1. Primary eye witness video with audio:
[ X link ending 1933089931347345596 in case the hyperlink itself doesn't work for any reason]
- Footage starts with aircraft directly overhead, give or take, (based on both sound & vision)
- 13 seconds from start until fireball clearly visible above roofline
2. Airport CCTV:
[X link ending 1933162059556159903 ]
- 49-50 seconds until impact and fireball clearly visible
Subtract the 13 secs noted in video #1 and this establishes the approximate moment the aircraft passes over the video witness's position when viewed from video #2 (CCTV):
49 - 13 = 36 secs into video 2
Estimated timeline (CCTV #2):
19s: rotate
31s: climb rate noticeably deteriorates (12s after TO / 18s from impact)
36s: estimated moment aircraft overflies eyewitness camera (17s after TO / 13s from impact)
38-40s: pitch up then descent begins (19-21s from TO / 9-11s from impact)
49s: first contact with ground (30s after TO / approx impact)
50s: fireball visible above rooftops
Conclusions from combining both videos:
- Aircraft overflies eyewitness camera roughly 13 secs before impact
- This is well after it has stopped climbing (~6 secs)
- This is also mere seconds before CCTV shows the aircraft pitch up and start to descend (which I believe I can substantiate in the eye witness video, although this is tougher to confirm with the naked eye from this viewing angle - someone may have to look more closely than I can this evening!)
- I have previously asked questions about the audio in video #1 and whether we can draw any conclusions regarding RAT deployment & engine thrust. There are strong opinions on both sides. Your personal view on this will influence your evaluation of what the videos show, but either way your theory needs to fit the timeline (or advance a different one).
So, anyone who is developing a theory ought to consider whether it is consistent with the following:-
- rate of climb decays to 0ft/m within 10-12 secs of rotation
- RAT (possibly) audible within 17s of rotation *
- pitch up shortly afterwards with no discernible increase in engine noise & unable to arrest descent
- impact with ground within 30 secs of rotation
* I recognise that the RAT deployment is not an established fact, but any theory that proposes RAT deployment needs to take into account this timeline in addition to the rest.
Alternatively, you are welcome to refute this simplistic, late night analysis of the limited video evidence.
June 14, 2025, 03:05:00 GMT
permalink Post: 11901101
Miscellaneous comments:
I have seen in manuals for other airliners that because the bogie tilt is by a hydraulic actuator, gravity deploying the gear means the gear doesn't tilt to landing position.
With the loss of centre-system pressure*, would you expect the bogies to tilt naturally? I.e. spring pressure holds the gear in the stowed tilt, a hydraulic cylinder pushes the gear to the landing tilt. No pressure means the gear returns to the 'stowed' tilt.
The tilt actuator is designed to be overridden when the bogie hits the ground, so perhaps it has some kind of intentional bypass and doesn't stay in place without continually applied hydraulic pressure.
If so, that would also point towards total loss of electrics and no attempt to raise the gear.
* 787 centre system is powered by two electric pumps, plus the RAT. The RAT hydraulic pump only powers flight controls, not the landing gear.
Electric loss:
Surely even total AC power loss shouldn't result in engine loss, even if the RAT doesn't come online. The FADECs have their own alternators, bare minimum flight control computers and actuators are available on battery (though probably result in some equivalent of Direct Law), and boost pumps are unnecessary at low altitude. Left/right EDPs will remain active if the engines are running at any serious speed; providing flight controls.
Poor crew reaction to ending up in direct law is possible but it's hard to see the electrical issues as a cause, not a symptom.
Anti-terrorism squad looks to be doing an excellent job (/s) and recovered a convenience-store-grade CCTV recorder, probably from somewhere on the campus it crashed into:
https://economictimes.indiatimes.com.../121823103.cms
With the loss of centre-system pressure*, would you expect the bogies to tilt naturally? I.e. spring pressure holds the gear in the stowed tilt, a hydraulic cylinder pushes the gear to the landing tilt. No pressure means the gear returns to the 'stowed' tilt.
The tilt actuator is designed to be overridden when the bogie hits the ground, so perhaps it has some kind of intentional bypass and doesn't stay in place without continually applied hydraulic pressure.
If so, that would also point towards total loss of electrics and no attempt to raise the gear.
* 787 centre system is powered by two electric pumps, plus the RAT. The RAT hydraulic pump only powers flight controls, not the landing gear.
Electric loss:
Surely even total AC power loss shouldn't result in engine loss, even if the RAT doesn't come online. The FADECs have their own alternators, bare minimum flight control computers and actuators are available on battery (though probably result in some equivalent of Direct Law), and boost pumps are unnecessary at low altitude. Left/right EDPs will remain active if the engines are running at any serious speed; providing flight controls.
Poor crew reaction to ending up in direct law is possible but it's hard to see the electrical issues as a cause, not a symptom.
https://economictimes.indiatimes.com.../121823103.cms
June 14, 2025, 03:39:00 GMT
permalink Post: 11901113
A few posts earlier desmotronic mentions the sole survivor saying he could feel thrust increasing. In addition he mentioned a loud bang just before impact. At no point has the survivor been quoted saying all engine power stopped, or the noise of the engines completely stopped. Even thrust reduction after takeoff is very noticeable in the cabin, so imagine if both engines would have quit. Not to discount anything at this stage, but this is puzzling regarding the double engine failure scenario (based on some grainy images of a RAT maybe being extended).
June 14, 2025, 03:42:00 GMT
permalink Post: 11901116
June 14, 2025, 06:53:00 GMT
permalink Post: 11901175
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.
1) The flap retraction would immediately result in progressive less lift, not only after full retraction . The time in the air could have been longer than your estimate, maybe enough time for full retraction
2) if 200 feet in MCP, why would that lead to a descent? Shouldn't that result in level flight?
3) wrong TOW / too low power setting sounds like a plausible event.Happened before. But with full power / TOGA set in the air ( which surely must have happened)I would expect at least a longer struggle rather than the constant descent. Just a gut feeling though, busdriver, no experience on 787. Maybe already in a power on stall. The only problem with this hypothesis is that it does not explain the gear down since there definitely was positive rate after rotation.
4) double engine failure too remote, no signs of flames etc. Forget it, agreed.
My guess remains inadvertant flaps retraction for what it's worth.
June 14, 2025, 07:18:00 GMT
permalink Post: 11901188
A summary of the more certain things we know about the accident so far:
The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.
Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction. What exactly caused the engine/electrical issues remains speculative. An action slip mistaking flaps for gear seems much less likely as due to the above, the correct selection was probably made.
From the videos of the last moments, there is strong evidence that the RAT was deployed, which has a very short list of possible triggers. The sole eye witness from inside describes power issues which lends credence.
Taken together, it seems that there was an event (or events) shortly after rotation that compromised both engines and the electrical system. There is no evidence yet of birdstrikes and continued engine operation *should* not be affected by the aircraft electrical system as they are independently/internally powered, so logic would have the engines failing first leading to a cascade of other problems. Something that affects all engines pretty much simultaneously is a rare beast but it has happened in the past; outside of a deliberate selection of the fuel and/or fire switches for both power plants there is fuel contamination, FOD and not much else. Its seems at least one FDR has been recovered so depending on where they take it for read-out, we should get some initial facts fairly shortly.
The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.
Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction. What exactly caused the engine/electrical issues remains speculative. An action slip mistaking flaps for gear seems much less likely as due to the above, the correct selection was probably made.
From the videos of the last moments, there is strong evidence that the RAT was deployed, which has a very short list of possible triggers. The sole eye witness from inside describes power issues which lends credence.
Taken together, it seems that there was an event (or events) shortly after rotation that compromised both engines and the electrical system. There is no evidence yet of birdstrikes and continued engine operation *should* not be affected by the aircraft electrical system as they are independently/internally powered, so logic would have the engines failing first leading to a cascade of other problems. Something that affects all engines pretty much simultaneously is a rare beast but it has happened in the past; outside of a deliberate selection of the fuel and/or fire switches for both power plants there is fuel contamination, FOD and not much else. Its seems at least one FDR has been recovered so depending on where they take it for read-out, we should get some initial facts fairly shortly.