2025-06-13T19:42:00
permalink Post: 11900845
2025-06-13T19:45:00
permalink Post: 11900847
3 users liked this post.
2025-06-13T20:04:00
permalink Post: 11900854
Question is why both engines lost power . Foreign object ingestion , contaminated fuel or both cutoff levels operated ? We do not know .
Any autothrust discussion is misleading since every pilot in that situation will firewall the levers whatever thrust reduction was selected for TO . the same is true for the RAT discussion- if enough hydraulic pressure was generated or not . The plane pitched up last second so there obviously was control until the end . Of course , without energy pulling alone will not bring you anywhere .
Why did both engines fail the same second as they would be cut off ???
Any autothrust discussion is misleading since every pilot in that situation will firewall the levers whatever thrust reduction was selected for TO . the same is true for the RAT discussion- if enough hydraulic pressure was generated or not . The plane pitched up last second so there obviously was control until the end . Of course , without energy pulling alone will not bring you anywhere .
Why did both engines fail the same second as they would be cut off ???
Actually not true. Remember the 737 with iced up itt probes that hit the Washington bridge?
a simple \x93yugga\x94 on the power levers would have prevented disaster.
probably irrelevant to this topic however
2025-06-13T20:50:00
permalink Post: 11900886
We're all shouting each other down with two main different theories on why the aircraft lost lift so shortly after takeoff.
1) Incorrect flap retraction causing the aircraft to lose lift and unable to recover the energy in time. (Not unheard of and plenty of reports where this has happened - albeit usually not to a crash).
2) Loss of engine thrust backed up two potential pieces of evidence that back up the RAT was deployed (apparent RAT sound, potential RAT seen on low res video).
It is impossible to know which of these is the case. Considering this summary of memory items is there the potential for a combination of both theories to have taken place?
Inadvertant flap retraction by PNF leading the PF to sense a sink and loss of lift. Pushes the thrust levers forward to the firewall and still the aircraft sinks. PF looking through the HUD and so very much 'outside focused' and doesn't realise that PNF has instead moved the flaps. PF defaults to memory items for loss of thrust on both engines before PNF can realise or communicate to PF what they've done, start switches are cut off which drops the RAT and from that point they're only heading one way. This would satisfy the strongly held belief that the RAT was extended, whilst also following the more likely initial cause of an action slip by PNF starting the sequence, rather than a dual engine failure.
1) Incorrect flap retraction causing the aircraft to lose lift and unable to recover the energy in time. (Not unheard of and plenty of reports where this has happened - albeit usually not to a crash).
2) Loss of engine thrust backed up two potential pieces of evidence that back up the RAT was deployed (apparent RAT sound, potential RAT seen on low res video).
It is impossible to know which of these is the case. Considering this summary of memory items is there the potential for a combination of both theories to have taken place?
Inadvertant flap retraction by PNF leading the PF to sense a sink and loss of lift. Pushes the thrust levers forward to the firewall and still the aircraft sinks. PF looking through the HUD and so very much 'outside focused' and doesn't realise that PNF has instead moved the flaps. PF defaults to memory items for loss of thrust on both engines before PNF can realise or communicate to PF what they've done, start switches are cut off which drops the RAT and from that point they're only heading one way. This would satisfy the strongly held belief that the RAT was extended, whilst also following the more likely initial cause of an action slip by PNF starting the sequence, rather than a dual engine failure.
As has been said many times as well, the landing gear retraction process appears to start as the bogies tilt, and then suddenly stops. Which rather suggests they did pull the gear lever. Based on the videos and the amount of speed the plane lost in the very brief sequence ovents, I'd say that the plane lost power a lot earlier than it would have in your theory.
Last edited by neila83; 13th Jun 2025 at 21:03 .
3 users liked this post.
2025-06-13T20:55:00
permalink Post: 11900891
The aircraft as I understand was on a turnround. Is there any element that a ground engineer would have adjusted or checked incorrectly in that standard turnround check, that may have led to duel fuel starvation, or similar issue end up with a unrecoverable loss of power. Obviously I\x92m assuming that involves the time taken for start, pushback, taxiing and TO roll before it manifests itself.
(bio many years in airport ops/atc, and watched an a/c trash engines as it rolled for TO. Reason, equipment was left in an intake that gently moved into the engine after start/push/taxi and commenced roll)
(bio many years in airport ops/atc, and watched an a/c trash engines as it rolled for TO. Reason, equipment was left in an intake that gently moved into the engine after start/push/taxi and commenced roll)
2025-06-13T21:30:00
permalink Post: 11900926
Having read all the posts, watched the videos and with a 30 year background interest in air safety, I have a nagging feeling that the engine fuel cut off switches were pulled just after take-off. I am not saying this with the intention of idle speculation, it is just that to me nothing else seems to make sense. To anyone disagreeing with this, I really hope you are right and I am wrong.
2025-06-13T21:57:00
permalink Post: 11900954
At this stage, at least two scenarios seem highly plausible:
1. Technical issue
Airliners rely on air/ground logic , which is fundamental to how systems operate.
There have been numerous crashes and serious incidents linked to this logic functioning incorrectly.
Some engineering tests require the air/ground switch to be set in a particular mode. If it's inadvertently left in engineering mode—or if the system misinterprets the mode—this can cause significant problems.
2. Pilot misselection of fuel control switches to cutoff
This is still a very real possibility. If it occurred, the pilot responsible may not have done it consciously—his mindset could have been in a different mode.
There’s precedent: an A320 pilot once inadvertently shut down both engines over Paris. Fortunately, the crew managed to restart them. Afterward, the pilot reportedly couldn’t explain his actions.
If something similar happened here, then when the pilots realized the engines had stopped producing thrust, pushing the levers forward would have had no effect. It’s easy to overlook that the fuel switches are in the wrong position—they're far from the normal scan pattern. And with the ground rushing up, the view outside would’ve been far more commanding.
Speaking personally, when I shut down engines at the end of a flight, I consciously force myself to operate each fuel switch independently and with full attention. I avoid building muscle memory that might lead to switching off both engines in a fast, well-practiced habit.
If this is a technical issue, I assume we’ll know soon enough.
1. Technical issue
Airliners rely on air/ground logic , which is fundamental to how systems operate.
There have been numerous crashes and serious incidents linked to this logic functioning incorrectly.
Some engineering tests require the air/ground switch to be set in a particular mode. If it's inadvertently left in engineering mode—or if the system misinterprets the mode—this can cause significant problems.
-
On the ground
, if the aircraft is incorrectly in
air mode
, some systems may be unavailable—such as wheel brakes, reverse thrust, or ground spoilers.
-
In the air
, if the aircraft is mistakenly in
ground mode
, flaps might auto-retract, and various layers of system protection may be disabled.
2. Pilot misselection of fuel control switches to cutoff
This is still a very real possibility. If it occurred, the pilot responsible may not have done it consciously—his mindset could have been in a different mode.
There’s precedent: an A320 pilot once inadvertently shut down both engines over Paris. Fortunately, the crew managed to restart them. Afterward, the pilot reportedly couldn’t explain his actions.
If something similar happened here, then when the pilots realized the engines had stopped producing thrust, pushing the levers forward would have had no effect. It’s easy to overlook that the fuel switches are in the wrong position—they're far from the normal scan pattern. And with the ground rushing up, the view outside would’ve been far more commanding.
Speaking personally, when I shut down engines at the end of a flight, I consciously force myself to operate each fuel switch independently and with full attention. I avoid building muscle memory that might lead to switching off both engines in a fast, well-practiced habit.
If this is a technical issue, I assume we’ll know soon enough.
3 users liked this post.
2025-06-13T22:13:00
permalink Post: 11900962
At this stage, at least two scenarios seem highly plausible:
1. Technical issue
Airliners rely on air/ground logic , which is fundamental to how systems operate.
There have been numerous crashes and serious incidents linked to this logic functioning incorrectly.
Some engineering tests require the air/ground switch to be set in a particular mode. If it's inadvertently left in engineering mode—or if the system misinterprets the mode—this can cause significant problems.
2. Pilot misselection of fuel control switches to cutoff
This is still a very real possibility. If it occurred, the pilot responsible may not have done it consciously—his mindset could have been in a different mode.
There’s precedent: an A320 pilot once inadvertently shut down both engines over Paris. Fortunately, the crew managed to restart them. Afterward, the pilot reportedly couldn’t explain his actions.
If something similar happened here, then when the pilots realized the engines had stopped producing thrust, pushing the levers forward would have had no effect. It’s easy to overlook that the fuel switches are in the wrong position—they're far from the normal scan pattern. And with the ground rushing up, the view outside would’ve been far more commanding.
Speaking personally, when I shut down engines at the end of a flight, I consciously force myself to operate each fuel switch independently and with full attention. I avoid building muscle memory that might lead to switching off both engines in a fast, well-practiced habit.
If this is a technical issue, I assume we’ll know soon enough.
1. Technical issue
Airliners rely on air/ground logic , which is fundamental to how systems operate.
There have been numerous crashes and serious incidents linked to this logic functioning incorrectly.
Some engineering tests require the air/ground switch to be set in a particular mode. If it's inadvertently left in engineering mode—or if the system misinterprets the mode—this can cause significant problems.
-
On the ground
, if the aircraft is incorrectly in
air mode
, some systems may be unavailable—such as wheel brakes, reverse thrust, or ground spoilers.
-
In the air
, if the aircraft is mistakenly in
ground mode
, flaps might auto-retract, and various layers of system protection may be disabled.
2. Pilot misselection of fuel control switches to cutoff
This is still a very real possibility. If it occurred, the pilot responsible may not have done it consciously—his mindset could have been in a different mode.
There’s precedent: an A320 pilot once inadvertently shut down both engines over Paris. Fortunately, the crew managed to restart them. Afterward, the pilot reportedly couldn’t explain his actions.
If something similar happened here, then when the pilots realized the engines had stopped producing thrust, pushing the levers forward would have had no effect. It’s easy to overlook that the fuel switches are in the wrong position—they're far from the normal scan pattern. And with the ground rushing up, the view outside would’ve been far more commanding.
Speaking personally, when I shut down engines at the end of a flight, I consciously force myself to operate each fuel switch independently and with full attention. I avoid building muscle memory that might lead to switching off both engines in a fast, well-practiced habit.
If this is a technical issue, I assume we’ll know soon enough.
On item 2, the video shows no asymmetry at any time, so there is only a symmetric failure of the engines possible. Back on a B747 classic, you could chop all 4 engines at the same time with one hand, on a B737, also, not so much on a B777 or B787. I would doubt that anyone used two hands to cut the fuel at screen height. Note, there was a B744 that lost one engine in cruise when a clip board fell off the coaming. Didn't happen twice, and it only happened to one engine.
Yes indeed, the moment they pulled the gear lever, as we see the gear begin the retraction process, and then suddenly stop. Almost as if they suddenly lost power.
We can see the landing gear retraction process begin. We see the bogies tilted in the second video. We can hear the RAT. We can see the RAT. We can see the flaps extended in the video and at the crash site. There isn't actually a single piece of evidence the flaps were raised, it's just a conclusion people jumped too before evidence began to emerge.
The crazy thing is, when the report comes out and there is no mention of flaps none of the people who have been pushing the flap theory will self reflect or learn anything. They'll think those of us who didn't buy into it were just lucky, rather than it being down to use of fairly simple critical thinking.
We can see the landing gear retraction process begin. We see the bogies tilted in the second video. We can hear the RAT. We can see the RAT. We can see the flaps extended in the video and at the crash site. There isn't actually a single piece of evidence the flaps were raised, it's just a conclusion people jumped too before evidence began to emerge.
The crazy thing is, when the report comes out and there is no mention of flaps none of the people who have been pushing the flap theory will self reflect or learn anything. They'll think those of us who didn't buy into it were just lucky, rather than it being down to use of fairly simple critical thinking.
Neila83 is correct, the gear tilt pre retraction is rear wheels low, and at the commencement of the selection of the retraction cycle (generally),
There is enough in the way of anomalies here to end up with regulatory action, and airlines themselves should/will be starting to pore over their systems and decide if they are comfortable with the airworthiness of the aircraft at this moment. A latent single point of failure is not a comfortable place to be. Inhibiting TCMA might be a good interim option, that system could have been negated by having the ATR ARM switches....(Both)... ARM deferred to the before takeoff checks. The EAFR recovery should result in action within the next 24-48 hours. Boeing needs to be getting their tiger teams warmed up, they can ill afford to have a latent system fault discovered that is not immediately responded to, and the general corporate response of "blame the pilots" is not likely to win any future orders.
I think we are about to have some really busy days for the OEM.
Not sure that Neila83 is that far off the mark at all.
Last edited by fdr; 14th Jun 2025 at 01:21 . Reason: corrected for B788 by Capt Bloggs!
8 users liked this post.
2025-06-13T23:21:00
permalink Post: 11900993
Combining all the bits and pieces of info from this thread so far, IMO we can theoretically sequence it thus using the video from the left:
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
4 users liked this post.
2025-06-14T01:11:00
permalink Post: 11901053
A long while ago I posted on the Rumour thread about a ban on drinks on the flight deck sent to a BA, A350 mid Atlantic. It was prompted by 2 separate instances of uncommanded unrecoverable engine shut downs due to drink spills across the fuel cut off switches. It was widely mocked by the professional pilots on here until proven to be absolutely factually correct. If we are into speculation why not a drink left on the flight deck tips on aircraft pitch up and spills across both fuel cut-switches. Just sayin
Hutch
Hutch
Last edited by T28B; 14th Jun 2025 at 01:43 . Reason: Bold is not necessary
1 user liked this post.
2025-06-14T09:20:00
permalink Post: 11901298
If this is correct, does it point more towards the engines having been erroneously shut down earlier, rather than a fuel starvation or contamination issue?
2 users liked this post.
2025-06-14T12:04:00
permalink Post: 11901413
My next question, again I believe not discussed, is what do the 787 Fuel Cutoff switches actually do? Obviously, they cut off the fuel supplies to the engines - pretty important in engine fire and other scenarios, but goes without saying. The real question is, what do they activate (or deactivate)? I'm assuming a simple solenoid valve, which is open when powered and closed when unpowered, but of course, there will (certainly) be Electro-Mechanical or Solid-State (Electronic) relays between the switches and the (solenoid valves).
I guess the next obvious question is, is there anything else that can turn off those Fuel Cutoff Valves - a computer condition for example. I'm assuming not, but I think it needs to be considered.
Taking each switch individually, next, since this is part of an electrical circuit, and of necessity must include Electrical Relays, there is certainly at least one and in all probability two electric Power Sources involved in this circuit. One supply which passes through the switch to activate the relay, and, I'm assuming, a second, higher current and probably higher voltage supply which drives the (solenoid?) valve.
As I see it, interrupting either supply will have the same effect - if the system is wired in the Positive-Postive sense, meaning a current through the switch causes the relay to pass a current through the (solenoid). If either of these supplies is cut, the Fuel Shutoffs will shut off the fuel. So, the question is, where do these supplies come from, and under what circumstances could they be cut off?
Sure, it looks to some (myself included) like a near simultaneous cutoff of both engines, but that doesn't have to have been caused by either of the pilots. I know there is huge redundancy built into the 787 Electrical Systems, but some of the evidence is suggesting that there was something not right with the plane's electrical system. I'm also fairly sure that there will be parts and places where certain faults can take the system down, despite the redundancy. I can't say where, but it's very difficult to design a perfect system, especially where there has to be transfers between multiple potential supplies and single actuators, motors or valves.
Having spent years repairing electrical and electronic systems, I know that the most difficult of all electrical faults are the intermittent ones. And I suspect that this is at the root of this crash. An intermittent or faulty AOA sensor has "caused" (provoked) multiple famous crashes... Can't find the one I'm looking for (pre-1980, I think) as the Max AOA issues dominate.
I can cite a very personal example, which involved the electrical supply to my house. I had several computers running 24x365 so of course, ran them off a UPS, which turned out to be a very good thing. I started to notice that at certain times, the UPS would activate - it would cut in and take over the computer loads, its alarm would go off to indicate a power fault. But the power was still on! This carried on for weeks and I initially blamed the UPS. Then, I noticed that it only happened on very hot afternoons... Long story short, the fault was caused by an electrical linesman, probably 30 years earlier, failing to tighten up a joint clamp on the phase wire to our house, across the street. Heating caused expansion then movement, and the power would momentarily go off then back on, and the UPS detected this. I note that this crash was on a hot day, and maybe this plane (which I believe was repositioned for the flight), had not been operating in such high temperatures recently, meaning the problem went unnoticed.
I guess the next obvious question is, is there anything else that can turn off those Fuel Cutoff Valves - a computer condition for example. I'm assuming not, but I think it needs to be considered.
Taking each switch individually, next, since this is part of an electrical circuit, and of necessity must include Electrical Relays, there is certainly at least one and in all probability two electric Power Sources involved in this circuit. One supply which passes through the switch to activate the relay, and, I'm assuming, a second, higher current and probably higher voltage supply which drives the (solenoid?) valve.
As I see it, interrupting either supply will have the same effect - if the system is wired in the Positive-Postive sense, meaning a current through the switch causes the relay to pass a current through the (solenoid). If either of these supplies is cut, the Fuel Shutoffs will shut off the fuel. So, the question is, where do these supplies come from, and under what circumstances could they be cut off?
Sure, it looks to some (myself included) like a near simultaneous cutoff of both engines, but that doesn't have to have been caused by either of the pilots. I know there is huge redundancy built into the 787 Electrical Systems, but some of the evidence is suggesting that there was something not right with the plane's electrical system. I'm also fairly sure that there will be parts and places where certain faults can take the system down, despite the redundancy. I can't say where, but it's very difficult to design a perfect system, especially where there has to be transfers between multiple potential supplies and single actuators, motors or valves.
Having spent years repairing electrical and electronic systems, I know that the most difficult of all electrical faults are the intermittent ones. And I suspect that this is at the root of this crash. An intermittent or faulty AOA sensor has "caused" (provoked) multiple famous crashes... Can't find the one I'm looking for (pre-1980, I think) as the Max AOA issues dominate.
I can cite a very personal example, which involved the electrical supply to my house. I had several computers running 24x365 so of course, ran them off a UPS, which turned out to be a very good thing. I started to notice that at certain times, the UPS would activate - it would cut in and take over the computer loads, its alarm would go off to indicate a power fault. But the power was still on! This carried on for weeks and I initially blamed the UPS. Then, I noticed that it only happened on very hot afternoons... Long story short, the fault was caused by an electrical linesman, probably 30 years earlier, failing to tighten up a joint clamp on the phase wire to our house, across the street. Heating caused expansion then movement, and the power would momentarily go off then back on, and the UPS detected this. I note that this crash was on a hot day, and maybe this plane (which I believe was repositioned for the flight), had not been operating in such high temperatures recently, meaning the problem went unnoticed.
3 users liked this post.
2025-06-14T12:43:00
permalink Post: 11901451
Even though there is no point speculating about the cause of this accident, it is the nature of the beast to have questions. As pilots (most of us at least), we do have an inquiring mindset.
My initial thoughts were an inadvertent flap retraction. But with the ‘evidence’ that has been presented over the last 48 hours, I think we can safely discard that option.
What we think we know is:
- RAT was deployed (highly possible)
- Gear was selected up, but did not operate (bogey tilted, doors remained closed)
- APU was ‘on’ (APU door open on after crash pictures)
- Flight path
Any of these observations, alone, would mean very little. However, in combination, they all point to a dual engine flameout just at/after the rotation. The aircaft has enough kinetic energy to reach roughly 150ft altitude, end then starts a shallow descent at ‘alpha max’ into the buildings ahead. The RAT deployed, APU attempted auto-start, gear was unable to retract.
I only wonder why the engines spooled down. Bird strike seems to be out of the question, so that leaves us with only a very few options, which include a software bug or a suicidal pilot (not a popular option, I understand, but we have to take all options into account).
What I don’t believe is incorrect FCU selections, since that would not explain the high AOA on impact. It also would not explain the RAT, no gear retraction or the APU inlet flap open. Another thing that is highly unlikely is any switching done by the pilots, especially RAT etc.. These airborne time is just too little, pilots usually don’t take any action below approximately 400ft, and these switches are so ‘underused’ that a pilot would not find them instantaneously in a high stress situation.
For me, a dual engine flameout seems the only possible explanation, now we only have to wait for its cause.
My initial thoughts were an inadvertent flap retraction. But with the ‘evidence’ that has been presented over the last 48 hours, I think we can safely discard that option.
What we think we know is:
- RAT was deployed (highly possible)
- Gear was selected up, but did not operate (bogey tilted, doors remained closed)
- APU was ‘on’ (APU door open on after crash pictures)
- Flight path
Any of these observations, alone, would mean very little. However, in combination, they all point to a dual engine flameout just at/after the rotation. The aircaft has enough kinetic energy to reach roughly 150ft altitude, end then starts a shallow descent at ‘alpha max’ into the buildings ahead. The RAT deployed, APU attempted auto-start, gear was unable to retract.
I only wonder why the engines spooled down. Bird strike seems to be out of the question, so that leaves us with only a very few options, which include a software bug or a suicidal pilot (not a popular option, I understand, but we have to take all options into account).
What I don’t believe is incorrect FCU selections, since that would not explain the high AOA on impact. It also would not explain the RAT, no gear retraction or the APU inlet flap open. Another thing that is highly unlikely is any switching done by the pilots, especially RAT etc.. These airborne time is just too little, pilots usually don’t take any action below approximately 400ft, and these switches are so ‘underused’ that a pilot would not find them instantaneously in a high stress situation.
For me, a dual engine flameout seems the only possible explanation, now we only have to wait for its cause.
Last edited by Senior Pilot; 14th Jun 2025 at 19:08 . Reason: Double posting of image
2025-06-14T12:56:00
permalink Post: 11901460
I asked this yesterday, and was told no. You have to pull them out before you can move them up or down. So you can't operate them if, say, your hand slips violently off the throttle lever and drops down into the switches.
3 users liked this post.
2025-06-14T13:07:00
permalink Post: 11901468
This crash reminds me of the crash of a 747 Military Transport plane at an airbase in Afghanistan.
Shortly after TO, the cargo shifted, the plane became very tail heavy and stalled a few hundred feet in the air. It was the weirdest sight. For what seems a few seconds, the plane just seemed to hang there, presumably on engine thrust.
In this crash, the problem also seems to occur soon after rotation, as if something inside moved in response to its change in attitude. Maybe a loose connection on a main bus cable that moved... Maybe only a millimetre. Or a tool left inside an electrical cabinet slid somewhere it shouldn't. The possibilities are numerous, and without a lot more information, there's no way to know what caused this. I suspect a major electrical fault, probably intermittent.
How long would it take to restart those engines after a Fuel Cutoff flame out? Is that what happened, just before impact?
Shortly after TO, the cargo shifted, the plane became very tail heavy and stalled a few hundred feet in the air. It was the weirdest sight. For what seems a few seconds, the plane just seemed to hang there, presumably on engine thrust.
In this crash, the problem also seems to occur soon after rotation, as if something inside moved in response to its change in attitude. Maybe a loose connection on a main bus cable that moved... Maybe only a millimetre. Or a tool left inside an electrical cabinet slid somewhere it shouldn't. The possibilities are numerous, and without a lot more information, there's no way to know what caused this. I suspect a major electrical fault, probably intermittent.
How long would it take to restart those engines after a Fuel Cutoff flame out? Is that what happened, just before impact?
2025-06-14T13:40:00
permalink Post: 11901495
Fuel cutoff switches
My next question, again I believe not discussed, is what do the 787 Fuel Cutoff switches actually do? Obviously, they cut off the fuel supplies to the engines - pretty important in engine fire and other scenarios, but goes without saying. The real question is, what do they activate (or deactivate)? I'm assuming a simple solenoid valve, which is open when powered and closed when unpowered, but of course, there will (certainly) be Electro-Mechanical or Solid-State (Electronic) relays between the switches and the (solenoid valves).
I guess the next obvious question is, is there anything else that can turn off those Fuel Cutoff Valves - a computer condition for example. I'm assuming not, but I think it needs to be considered.
Taking each switch individually, next, since this is part of an electrical circuit, and of necessity must include Electrical Relays, there is certainly at least one and in all probability two electric Power Sources involved in this circuit. One supply which passes through the switch to activate the relay, and, I'm assuming, a second, higher current and probably higher voltage supply which drives the (solenoid?) valve.
As I see it, interrupting either supply will have the same effect - if the system is wired in the Positive-Postive sense, meaning a current through the switch causes the relay to pass a current through the (solenoid). If either of these supplies is cut, the Fuel Shutoffs will shut off the fuel. So, the question is, where do these supplies come from, and under what circumstances could they be cut off?
Sure, it looks to some (myself included) like a near simultaneous cutoff of both engines, but that doesn't have to have been caused by either of the pilots. I know there is huge redundancy built into the 787 Electrical Systems, but some of the evidence is suggesting that there was something not right with the plane's electrical system. I'm also fairly sure that there will be parts and places where certain faults can take the system down, despite the redundancy. I can't say where, but it's very difficult to design a perfect system, especially where there has to be transfers between multiple potential supplies and single actuators, motors or valves.
Having spent years repairing electrical and electronic systems, I know that the most difficult of all electrical faults are the intermittent ones. And I suspect that this is at the root of this crash. An intermittent or faulty AOA sensor has "caused" (provoked) multiple famous crashes... Can't find the one I'm looking for (pre-1980, I think) as the Max AOA issues dominate.
I can cite a very personal example, which involved the electrical supply to my house. I had several computers running 24x365 so of course, ran them off a UPS, which turned out to be a very good thing. I started to notice that at certain times, the UPS would activate - it would cut in and take over the computer loads, its alarm would go off to indicate a power fault. But the power was still on! This carried on for weeks and I initially blamed the UPS. Then, I noticed that it only happened on very hot afternoons... Long story short, the fault was caused by an electrical linesman, probably 30 years earlier, failing to tighten up a joint clamp on the phase wire to our house, across the street. Heating caused expansion then movement, and the power would momentarily go off then back on, and the UPS detected this. I note that this crash was on a hot day, and maybe this plane (which I believe was repositioned for the flight), had not been operating in such high temperatures recently, meaning the problem went unnoticed.
I guess the next obvious question is, is there anything else that can turn off those Fuel Cutoff Valves - a computer condition for example. I'm assuming not, but I think it needs to be considered.
Taking each switch individually, next, since this is part of an electrical circuit, and of necessity must include Electrical Relays, there is certainly at least one and in all probability two electric Power Sources involved in this circuit. One supply which passes through the switch to activate the relay, and, I'm assuming, a second, higher current and probably higher voltage supply which drives the (solenoid?) valve.
As I see it, interrupting either supply will have the same effect - if the system is wired in the Positive-Postive sense, meaning a current through the switch causes the relay to pass a current through the (solenoid). If either of these supplies is cut, the Fuel Shutoffs will shut off the fuel. So, the question is, where do these supplies come from, and under what circumstances could they be cut off?
Sure, it looks to some (myself included) like a near simultaneous cutoff of both engines, but that doesn't have to have been caused by either of the pilots. I know there is huge redundancy built into the 787 Electrical Systems, but some of the evidence is suggesting that there was something not right with the plane's electrical system. I'm also fairly sure that there will be parts and places where certain faults can take the system down, despite the redundancy. I can't say where, but it's very difficult to design a perfect system, especially where there has to be transfers between multiple potential supplies and single actuators, motors or valves.
Having spent years repairing electrical and electronic systems, I know that the most difficult of all electrical faults are the intermittent ones. And I suspect that this is at the root of this crash. An intermittent or faulty AOA sensor has "caused" (provoked) multiple famous crashes... Can't find the one I'm looking for (pre-1980, I think) as the Max AOA issues dominate.
I can cite a very personal example, which involved the electrical supply to my house. I had several computers running 24x365 so of course, ran them off a UPS, which turned out to be a very good thing. I started to notice that at certain times, the UPS would activate - it would cut in and take over the computer loads, its alarm would go off to indicate a power fault. But the power was still on! This carried on for weeks and I initially blamed the UPS. Then, I noticed that it only happened on very hot afternoons... Long story short, the fault was caused by an electrical linesman, probably 30 years earlier, failing to tighten up a joint clamp on the phase wire to our house, across the street. Heating caused expansion then movement, and the power would momentarily go off then back on, and the UPS detected this. I note that this crash was on a hot day, and maybe this plane (which I believe was repositioned for the flight), had not been operating in such high temperatures recently, meaning the problem went unnoticed.
2 users liked this post.
2025-06-14T13:43:00
permalink Post: 11901499
Reports coming in that Indian regulator has sent out a note for inspection of all GenX engines on the 787
2025-06-14T14:04:00
permalink Post: 11901512
A question for B787 pilots or mechanics.
Is it correct to assume that the EFSOV valves are actuated by the fuel flow and controlled by an electric signal coming directly from the relevant EEC. Meaning that the simultaneous closing of the 2 valves would require an improbable simultaneous failure of the 2 EEC, or that the 2 fuel switches are flipped from "run" to "cut-off" at almost the same time, feeding the same command to the 2 EEC.
And that the spar fuel valves are electrically actuated with the power coming from the hot battery bus and the signal coming from the aft electronic bay (possibly from the same control unit)?
(Note: not pretending to be a commercial pilot; just IR rated PPL).
Is it correct to assume that the EFSOV valves are actuated by the fuel flow and controlled by an electric signal coming directly from the relevant EEC. Meaning that the simultaneous closing of the 2 valves would require an improbable simultaneous failure of the 2 EEC, or that the 2 fuel switches are flipped from "run" to "cut-off" at almost the same time, feeding the same command to the 2 EEC.
And that the spar fuel valves are electrically actuated with the power coming from the hot battery bus and the signal coming from the aft electronic bay (possibly from the same control unit)?
(Note: not pretending to be a commercial pilot; just IR rated PPL).
1 user liked this post.
2025-06-14T14:09:00
permalink Post: 11901517
Max EGzt and autorelight
Combining all the bits and pieces of info from this thread so far, IMO we can theoretically sequence it thus using the video from the left:
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
In-flight, the Autorelight function should attempt to restart the engine as soon as a flameout is detected, and for an engine flaming out at high power it might catch it before it even goes sub-idle. Generally, Autorelight will continue attempting until some cutoff N2 at which time it will stop attempting, or if the pilot move the fuel switch to Cutoff. And while the EEC is still powered (via its own PMA) down to roughly 10% N2, the ignition exciters required for Autorelight do get their power from the airplane.
2025-06-14T16:21:00
permalink Post: 11901619
During the nearly two years that elapsed between AF 447 disappearing and the recovery of the flight data recorders nobody suggested that the PF might have, unwittingly, flown the aircraft, stalled, into the ocean.
AI 171 may prove to also have a totally unpredicted cause.
AI 171 may prove to also have a totally unpredicted cause.
I\x92m absolutely not speculating this is the case here, but could you not achieve the effect this flight suffered by just switching off the fuel control switches at 100ft on takeoff?
There are now so many assumptions based on the assumed state of flap, RAT etc that it\x92s becoming pointless speculation.