Page Links: First 1 2 3 4 5 6 7 8 9 10 11 Next Last Index Page
BrogulT
June 12, 2025, 21:22:00 GMT permalink Post: 11899748 |
IMO the problem is the relentless comments by people that apparently think they will win something by cracking the case or "calling it first" or those that can look at some AI rendering of a blurry picture and conclude they know the flap settings. Or concluding that a likely cause for this crash was that both engine master switches were turned off. Of course dual fuel cutoff is a remote but possible answer, but not one worth speculating about at this point let alone concluding that's what happened. Last edited by BrogulT; 12th June 2025 at 22:47 . |
violator
June 12, 2025, 22:34:00 GMT permalink Post: 11899800 |
One example of fuel contamination causing a significant loss of thrust on both engines at low altitude. But it seems extremely unlikely for contaminated fuel to impact both engines at exactly the same time, with no asymmetry and no surges or smoke. What can cause a sudden catastrophic loss of thrust on both engines at exactly the same time? Birds (but no apparent surges) Inadvertent movement of the fuel cut off switches (which would be an incredible error but I suppose it could conceivably be muscle memory having done so recently after the last leg\x85weirder things have happened. Remember the 767 events of the late 80s) Intentional shutdown of the engines (pilot suicide has happened before) Some catastrophic electrical/FADEC/engine interface failure (which I highly doubt is feasible in a modern 1309 aircraft) I can\x92t think of any others\x85 |
notfred
June 13, 2025, 00:12:00 GMT permalink Post: 11899855 |
From the airport CCTV video it looks to me like a normal takeoff and start of climb, until suddenly there's a loss of climb performance with no obvious upset at that point. From the picture of the wing post crash it looks like the flaps were still deployed (N.B. based on pre-accident photos that's the right wing so closest to the camera is aileron and flaps are further away, damage had me confused first time), so I'm going with loss of thrust rather than flap retraction.
From the videos from bystanders it looks like RAT deployment (both sound and zoomed in pictures) rather than thrust lever retard, and that would also explain failure to retract gear - if you are dealing with both engines out at that altitude then gear isn't your first thought. From the airport CCTV video I don't see anything that looks like bird strikes at that point in the climb i.e. no obvious flocks of birds, no smoke out of the engines, no slewing one way as one engine fails and then the other is cut by accident - plus you wouldn't cut the engine at that point, you'd climb on one engine and then sort it out. Even fuel contamination or water build up in both tanks is likely to result in one engine failing a few seconds before the other. So I can't come up with anything other than both fuel cutoff switches that would result in loss of thrust and RAT deployment. Looking at a picture of the cutoff switches https://www.nycaviation.com/2013/08/...is-fired/30179 I don't see how they get hit by accident. I'm confused, hope we get an FDR / CVR readout soon. |
Doors to Automatic
June 13, 2025, 01:31:00 GMT permalink Post: 11899908 |
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.
|
Sailvi767
June 13, 2025, 01:49:00 GMT permalink Post: 11899917 |
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.
|
tdracer
June 13, 2025, 02:18:00 GMT permalink Post: 11899930 |
Determined to be an ergonomics problem with the switch layout in the flightdeck. Early 767s (JT9D and CF6-80A) had a supervisory "EEC" (Electronic Engine Control - Boeing still uses "EEC" to identify what most people call the FADEC on modern engines). The procedure if an EEC 'failed' was to switch both EECs off (to prevent excessive throttle stagger - unlike FADEC, the engine could operate just fine with a supervisory EEC failed). Problem was that the EEC ON/OFF switch was located on the aisle stand - right above the fuel cutoff switches. Turned out 'muscle memory' was when the pilot reached down there, it was usually to turn the fuel ON or OFF - which is what they did. Fortunately realizing what he'd done wrong, the pilot quickly restored the switches to RUN and both engines recovered. And yes, they continued on to their destination (RAT was still deployed since there is no way to retract it in-flight). Previous event was with JT9D engines (United IIRC). In that case, only one engine recovered (second engine went into an unrecoverable stall), they simply came back around and did a single engine landing. Realizing the ergonomic issue, the EECs were relocated to the pilot's overhead (retrofit by AD). To the best of my knowledge, there hasn't been a repeat of an inadvertent dual engine shutdown since the EEC switches were relocated. It's also very difficult to 'accidentally' move the switches as there is a locking detent - the switch must be pulled out slightly before it can be moved to CUTOFF. Last edited by T28B; 13th June 2025 at 02:22 . Reason: again, broke up the text to be reader friendly, great input! |
Arrowhead
June 13, 2025, 09:03:00 GMT permalink Post: 11900213 |
https://assets.publishing.service.go...211_G-POWN.pdf
One example of fuel contamination causing a significant loss of thrust on both engines at low altitude. But it seems extremely unlikely for contaminated fuel to impact both engines at exactly the same time, with no asymmetry and no surges or smoke. What can cause a sudden catastrophic loss of thrust on both engines at exactly the same time? Birds (but no apparent surges) Inadvertent movement of the fuel cut off switches (which would be an incredible error but I suppose it could conceivably be muscle memory having done so recently after the last leg…weirder things have happened. Remember the 767 events of the late 80s) Intentional shutdown of the engines (pilot suicide has happened before) Some catastrophic electrical/FADEC/engine interface failure (which I highly doubt is feasible in a modern 1309 aircraft) I can’t think of any others… I cant think of any reason for electrical failure and "no thrust" (as per statements) without any visual cues other than (a) suicide, or (b) starvation. Is there any electrical failure that can cause fuel valves to close? I dont fly Boeing, so can any Dreamliner driver explain what conditions could trigger an overspeed and auto engine shutdown (quote from Google below)? Would short runway, and hot/low QNH do it? Also, what happened to the order demanding a full power down/recycle every 51 days? The EEC has build in protections to protect the engine. One of these protections is the Engine Overspeed Protection, when the core engine exceeds 120% the EEC shuts off the fuel to the applicable engine. Last edited by Arrowhead; 13th June 2025 at 09:46 . |
tumtiddle
June 13, 2025, 10:10:00 GMT permalink Post: 11900286 |
One has to assume that, given the seeming lack of lateral deviation from the flight path, and with no obvious yawing or rudder input visible on the videos, there's only two realistic conclusions here? Simultaneous dual engine failure of unknown cause if the RAT was indeed deployed; or flaps reduced too early leading to a stall if the RAT wasn't deployed.
Evidence in this thread would lean me toward the RAT deployed and therefore dual engine out scenario. As for the cause of that, well, only a couple of likely scenarios exist that could cause simultaneous shutdown of both engines, including mistaken or intentional use of the fuel cutoff levers. |
C2H5OH
June 13, 2025, 11:32:00 GMT permalink Post: 11900388 |
One has to assume that, given the seeming lack of lateral deviation from the flight path, and with no obvious yawing or rudder input visible on the videos, there's only two realistic conclusions here? Simultaneous dual engine failure of unknown cause if the RAT was indeed deployed; or flaps reduced too early leading to a stall if the RAT wasn't deployed.
Evidence in this thread would lean me toward the RAT deployed and therefore dual engine out scenario. As for the cause of that, well, only a couple of likely scenarios exist that could cause simultaneous shutdown of both engines, including mistaken or intentional use of the fuel cutoff levers. |
pampel
June 13, 2025, 11:35:00 GMT permalink Post: 11900390 |
Evidence in this thread would lean me toward the RAT deployed and therefore dual engine out scenario. As for the cause of that, well, only a couple of likely scenarios exist that could cause simultaneous shutdown of both engines, including mistaken or intentional use of the fuel cutoff levers.
|
Sailvi767
June 13, 2025, 12:34:00 GMT permalink Post: 11900458 |
If the fuel was cut off, how long would it take until the engines spooled down? How long would it take, given wind-milling etc, for that to result in a loss of power? I'd love to see a timeline of the flight with the fuel being cut off that is remotely compatible with the events we saw, because I don't think it's possible.
Last edited by Sailvi767; 13th June 2025 at 13:16 . |
aerobat77
June 13, 2025, 12:44:00 GMT permalink Post: 11900472 |
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 ??? |
sSquares
June 13, 2025, 12:48:00 GMT permalink Post: 11900479 |
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 ??? The "gear-up" places additional load on the hydraulic pumps and the result of that is step increase of load on the generators. Was this the trigger of the failures? |
violator
June 13, 2025, 12:56:00 GMT permalink Post: 11900487 |
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 ??? Let\x92s be careful about absolutes. Emirates 521 and Turkish 1951 are both examples of crews not firewalling the thrust levers despite low energy. The late pitch up could be due to the onset of a stall not an order from the crew. TCMA is function which can reduce thrust on both engines simultaneously. It had done so in error in the past resulting in an AD. It uses air/ground logic so that it only operates on the ground, however note that at the point of thrust loss the gear is still down without any movement of the gear or doors. I would expect gear retraction to start before that height. Could we imagine an air/ground logic fault inhibiting gear retraction and allowing TCMA, which triggered (for whatever reason!) causing dual thrust loss? I would expect this to be in the realms of a combination of failures shown to be extremely impossible, but\x85 |
HUTCHP
June 13, 2025, 14:18:00 GMT permalink Post: 11900557 |
One has to assume that, given the seeming lack of lateral deviation from the flight path, and with no obvious yawing or rudder input visible on the videos, there's only two realistic conclusions here? Simultaneous dual engine failure of unknown cause if the RAT was indeed deployed; or flaps reduced too early leading to a stall if the RAT wasn't deployed.
Evidence in this thread would lean me toward the RAT deployed and therefore dual engine out scenario. As for the cause of that, well, only a couple of likely scenarios exist that could cause simultaneous shutdown of both engines, including mistaken or intentional use of the fuel cutoff levers. Hutch |
flapassym
June 13, 2025, 20:04:00 GMT 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 ??? 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 |
jumpseater
June 13, 2025, 20:55:00 GMT 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) |
maxmanx
June 13, 2025, 21:30:00 GMT 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.
|
appruser
June 13, 2025, 23:21:00 GMT 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. |
bols59
June 14, 2025, 01:11:00 GMT 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 Last edited by T28B; 14th June 2025 at 01:43 . Reason: Bold is not necessary |
Page Links: First 1 2 3 4 5 6 7 8 9 10 11 Next Last Index Page