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Blake777
2025-06-15T13:54:00 permalink Post: 11902489 |
There's some possible fuel contamination mechanisms which would only affect one aircraft
- The fuel truck\x92s water-absorbing \x93monitor\x94 element breaks up, the first aircraft after the break gets the bead slug; later uplifts may be clear once the hose is flushed. The beads jam metering valves almost immediately. - After pipe maintenance, the first few hundred litres can carry residual cleaning surfactant that strips protective films and causes filter-monitor \x93soap lock\x94. - Biofilm growth happens inside one aircraft\x92s wing tanks when it sits in humid conditions or does short hops with warm fuel. On the next flight the biofilm shears off, blocks strainers, 1 user liked this post. |
EGPI10BR
2025-06-15T14:27:00 permalink Post: 11902507 |
A little bit tangential here, thinking about this Mayday call (the exact contents of which haven't been verified, but have been variously reported as "no power", or "lost power" ) , if in front of you on the PFD, in large red letters, you have the words ENG FAIL, why would you say, "no power"? Seems a bit strange. Why not say "engine failure" or "no thrust"?
Could it be that "No power" may have meant the whole cockpit went dark? ie. A total electrical failure or huge short (survivor's bang) initiating RAT deployment and apu autostart. Doesn't explain loss of thrust explicitly but if there was a massive electrical issue, and critical data was lost (thinking air/ground switch position and other fundamentals), would dual engine shutdown be a possibility? Simultaneous FADEC failure? Exceptionally remote possibility perhaps, but by definition these accidents are exceptionally remote. If the RAT deployed we know there was definitely an electrical issue - how bad was it, though? Thinking about the possibility of an electrical failure causing an engine (and instrumentation) failure rather than the other way around. Over to the experts on this. Misty. 1 user liked this post. |
87guy
2025-06-15T14:35:00 permalink Post: 11902509 |
My first post here...I feel I need to, due to some posts I have read. As a 787 pilot who has flown Embraer, Airbus, 767 and the 787-8/-9, I am saddened by many of the posts on this thread.
Some of you should be ashamed. Blaming the pilots before anyone has any idea what transpired.Short takeoff, improper flap/no flap setting, retracting the flaps instead of the gear, shutting down the wrong engine. In ANY other situation these actions would be laughable, and an insult to proffessional pilots the world over. Some commenting about the flaps even after pictures have shown that the flaps are extended. Also numerous people posting regarding shutting the wrong engine being shut down without any evidence to back this up. Videos clearly showing that the RAT was extended indicates that something very serious/catastrophic happened prior to this hull loss. People...this is the Proffessional Pilot's Rumour Network...Not the National Enquirer!!! I would urge everyone to WAIT for the report. Unbelievable. 11 users liked this post. |
Screamliner
2025-06-15T15:11:00 permalink Post: 11902541 |
I'm reading a lot of the comments, speculation is something we all like, but some things just do not add up, even with a RAT deployed
if they had dual engine failure around 50 feet where you raise the gear, how can they still find the energy to climb, since they would be at VR/V2 speed (not V2+20 at that altitude, what VNAV would command after take off, especially with a take off weight of around 205/210 tons, the 787 wings are amazing but not miracles if they had a normal departure, why did they not raise the gear, they had a positive rate since they were climbing and the speed according to ADS-B was a constant. if they were single engine ! this would have saved them with this weight and weather, one of the first things you learn when EFATO with a 787, raise the gear, your climb performance increases dramatically Intersection take off can be ruled out: if they did an intersection departure with they're genex 64-70K engines, they would have had a take off limited weight of around 172 tons, I estimate that they were close to 205/210 tons, (max zfw of around 161 tons and around 45/50 tons of fuel) even full length would have been a stress for the engines, with the prevailing weather conditions, they would have never made it, full length is already difficult. When we see the video, the airplane is still climbing / flying straight and level (not losing altitude), yet we hear what we think might be the RAT, I can't imagine that they had the kinetic energy to do this with no engines. if they had dual engine failure, they would have been a brick, Hot and High, no thrust, flaps 5, zero chance. flickering of lights etc. seen by the survivor and the loud bang heard, I would not trust pax observations, because of the things they had to go through, also and I've said this before, if it was a loud bang, where is the smoke and fire in the engines, or in the video, its not audible lets see what the report will say, but it it could be a lot to swallow for some Last edited by T28B; 15th Jun 2025 at 16:30 . Reason: cleaned up formatting 1 user liked this post. |
OPENDOOR
2025-06-15T16:06:00 permalink Post: 11902592 |
Trying to keep an open mind, but\x85.
Is no one surprised the lone survivor remembers a bang just before impact, and other things like apparently emergency lights, but has not mentioned the power going from takeoff power to nothing. Even the power change at thrust reduction altitude is often very noticeable in the cabin, so it surprises me nothing about the noise (and startle/panic) of full-power to no-power has been mentioned. I think we are getting into absurd scenarios trying to make the scenario of a simultaneous double engine failure just after liftoff fit, based on perhaps not the best evidence. ​​​​​​​ 2 users liked this post. |
Gupeg
2025-06-15T16:46:00 permalink Post: 11902623 |
Flightradar24 (I know, I know) has a short blog on the (very minimal) ADS-B data available. There's only around 4s of useful data available from 21ft o 71ft altitude (last packet received 0.8s later), But: it's odd seeing the speed DROPPING shortly after takeoff. Even if you calculate total energy (kinetic + potential) it's falling, i.e. the engines aren't producing thrust. (In fairness reported speed doesn't match my calculated speeds, but even with mine I don't see power). Also: if you assumed no thrust from 71ft AGL @ 172kt you'd reach 250ft at 160kt. Isn't that roughly where they ended up? Noisy data, but this suggests the engines stopped producing power almost as soon as the wheels left the ground. (If someone could download a CSV of another similar flight and send to me I can do a compare and contrast of Total Energy)
1. You might mathematically start at TE=0 at start of takeoff-roll, and treat drag as minimal until rotation. 2. Typically rotation will be to say 15deg nose up, but flight path will be much less (5deg? for heavy hot 787). Once that rotation is complete, aircraft will stop accelerating. Therefore engine thrust (energy gain) equals gain in PE - drag x time. 3. This might give a better insight into where energy gain/loss became unusual? Looking at the raw data in your post, and given the speeds are likely IAS based i.e. can be affected by wind, I don't see the IAS loss as equating to dual engine failure i.e. zero thrust - but could be wrong. Once a heavy airliner gets to lift off the acceleration is reduced (drag) and the decays to zero as PE gain kicks in. Ditto a time / distance to the crash site might give some energy info? Looks like the crash site is 50' (?) below the airfield (Google Earth will give more). I think you are doing an interesting study on the absence of other info ![]() |
Engineless
2025-06-15T17:15:00 permalink Post: 11902643 |
I think it needs to be said again that pretty much anything can happen to the aircraft systems and the engines will carry on running - this is by design as they have independent FADEC and power supplies and at sea level fuel will get through without boost pumps. You could almost saw the wing off the fuselage and the engine would still produce thrust, TCMA notwithstanding.
We don\x92t know yet what actually triggered the RAT from the relatively short list but every item on it means there is a serious/critical failure(s). The flight path suggests that it was a double engine failure or shutdown (commanded or uncommanded) as anything else should have left the aeroplane in a poor state but able to climb away . Secondly, as a (now ex) glider pilot who remains extremely interested in aviation in most of its forms, this discussion has been an education and thought-provoking, as it so frequently is whenever I lurk here (usually without logging in). Thank you all for sharing your knowledge, expertise and thoughts. To my mind the above post (especially the sentence I highlighted) is amongst the best (and most succinct) summary of what the pilots likely faced, with little to no time to resolve the situation. I cannot imagine those last few seconds and my heart goes out to them, the passengers and the many loved ones left behind. If there is any good that can come of this, it is that the cause is found quickly, with no bias, and steps are taken to ensure the same holes in the cheese cannot happen again. 7 users liked this post. |
adfad
2025-06-15T17:16:00 permalink Post: 11902645 |
When we see the video, the airplane is still climbing / flying straight and level (not losing altitude), yet we hear what we think might be the RAT, I can't imagine that they had the kinetic energy to do this with no engines. if they had dual engine failure, they would have been a brick, Hot and High, no thrust, flaps 5, zero chance.
The original mobile video (not the copy from someones phone screen) clearly sounds like a RAT but what does the engine itself sound like - is it idle or reduced in some way? What is the minimum amount of thrust that would need to be lost to stop climbing and sink back down - it took 30 seconds from leaving the ground to impact from the CCTV and the first 15 was climbing. I would look carefully at the fact that the PCU still has the technical ability to tell all AC generator control units to turn off via software, as proven in the documented and fixed 248-day software issue. 1 user liked this post. |
StuntPilot
2025-06-15T18:15:00 permalink Post: 11902683 |
Visual evidence the rat was deployed, audio evidence the rat was deployed, evidence the APU inlet door was open, evidence the gear retraction was interrupted, evidence there was very little engine noise after departure, very obvious evidence that the aeroplane didn\x92t have enough thrust to stop it descending into the ground. All of this strongly suggests that both engines were to all intents and purposes, and for want of a better word, \x91failed\x92 now that could be intentional, accidental or because of some sort of technical malfunction or external factor. Nothing conclusive and no answers as to how or why, but not quite as wildly stabbing in the dark as your post would infer.
2 users liked this post. |
njc
2025-06-15T19:03:00 permalink Post: 11902726 |
![]() I'd phrase it differently: the frequency (and harmonics) of the noise are consistent with it being a RAT. If you then assume that it was a RAT and infer distance and speed curves from the Doppler variation, you get plausible values for an aircraft. But the two things are somewhat linked so you can't really treat the second thing as confirmation of the first. (FWIW, I'm personally quite satisfied that it was indeed a RAT on the audio.) 4 users liked this post. |
sorvad
2025-06-15T19:15:00 permalink Post: 11902740 |
We agree that there was a lack of thrust. Possibly caused by a dual engine failure. But the sharpest frames in the video do NOT show the RAT and this is counter evidence to the RAT theory. If there were substantial technical failures who knows what sounds could be generated. I find the evidence weak at best. And we immediately get into a chicken-egg problem: did some power issue of unknown nature cause an engine failure or did a dual engine failure occur, resulting in a power loss? Both are extremely unlikely and need to be backed by quality evidence. The video is not it, in my opinion. I don't know the APU intake mechanism and whether it could open after the impact.
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Alty7x7
2025-06-15T20:23:00 permalink Post: 11902791 |
Engine failure with electrical power loss
We agree that there was a lack of thrust. Possibly caused by a dual engine failure. But the sharpest frames in the video do NOT show the RAT and this is counter evidence to the RAT theory. If there were substantial technical failures who knows what sounds could be generated. I find the evidence weak at best. And we immediately get into a chicken-egg problem: did some power issue of unknown nature cause an engine failure or did a dual engine failure occur, resulting in a power loss? Both are extremely unlikely and need to be backed by quality evidence. The video is not it, in my opinion. I don't know the APU intake mechanism and whether it could open after the impact.
Tdracer earlier confirmed that an airplane electrical power loss would allow engines to keep running , because 1) engines are fully-capable of suction feed operation in takeoff envelope (if boost pumps lost), and 2) the EECs are powered by their own PMAs when running and to substantially below idle (I recall roughly 10% N2). Airplane powers the EEC for ground starts, prior to PMA coming online, and as backup to the PMA after that. Related: Engine igniters are powered by the aircraft. So theoretical full loss of aircraft power would disable Autorelight upon a flameout. Ignitors typically don't make the cut for most-essential battery-only loads because it would also take an engine flameout, and the airplane past V1 in ground roll can fly fine on one engine that can achieve takeoff thrust. Autorelight is relevant - if there was a single-engine failure post V1, autorelight will attempt to relight the engine, so there is no need for a pilot to try to cycle the fuel switch to reset the EEC (potentially grabbing the wrong one), or to otherwise intervene. In such a circumstance, they need to trust their training. I've heard accounts that the most likely pilot instinct in such a situation would be to push the throttle(s) forward. Finally - there was talk earlier about accidentally cutting the fuel switches - and it was duly noted that they have to be pulled out over the detent, so very unlikely. The same cutoff effect could be achieved with the engine fire handle(s), right behind the fuel switches on the pedestal - though they are an upward pull, so also not subject to inadvertent or accidental engagement. |
Tu.114
2025-06-15T21:17:00 permalink Post: 11902850 |
The electrical failure is rather a chicken-egg question.
Not knowing the 787, I\xb4d find it extremely hard to believe that a massive electrical failure would kill the engines. I gather from this thread that the landing gear retraction is driven by the electrically-powered Center hydraulic system. Retracting the gear is hard work for the system and it will put a strain on the two pumps and their supplying electric circuits, and the time of the alleged total power loss would seem to be in the vicinity of the suitable time to retract the gear. But if there was some freak epidemic failure this inflicted upon the aircraft electrics, it is hard to imagine that this would affect both engines. There are still the autonomous FADEC governing them that run on their own internal generators (with a small external power source from the main systems, should the permanent magnet alternators fail) and do everything they can to keep the engine alive. As long as there is fuel flowing into the feed pipes, the engine should be kept running by the FADECs, and that this does not require the large tank pumps at low altitudes has been established in this thread. Consequently, I\xb4d deem it plausible that the alleged power failure must have been a consequence of whatever happened to the engines. After all, the engines drive the available generators at this stage of flight, the APU with its additional generators is apparently not run for takeoff on the 787. I find it logically much easier to wrap my head around a situation in which an engine failure takes along the generators than one in which a massive, epidemic electric breakdown kills the engines. |
Captain Fishy
2025-06-15T21:56:00 permalink Post: 11902882 |
Do not discount the mistaken early flap retraction scenario too easily. Mull on this:
PF commanded gear up on attaining positive rate of climb, fixating on the HUD. PM mistakenly raise flap lever from 5 to Flap 1 gate. Thrust reduced to Climb Thrust. Landing gear remained deployed. Massive loss of lift misidentified as loss of thrust. If any one pilot just had a dual engine failure scenario on a recent sim ride, brain and muscle memory would jump to loss of thrust in dual engine, prompting them to accomplish the recall memory items which called for both engine fuel control switches to CUTOFF and then RUN, and physically deployed the RAT. There would be immediate loss of thrust with the engine taking time to recover , if at all, at such low airspeed! The rest is left for Ppruners\x92 imagination.😖🥴😬 A loss of lift AND thrust at this critical juncture could have had caused this awful disaster. I think the data recorders have already revealed the cause but If it's this, then I don't think we will hear much anytime soon. |
sevenfive
2025-06-15T22:45:00 permalink Post: 11902924 |
Experienced 777 driver. Have tried to solve the puzzle. Looked carefully at the video in this article many times - see below and use full screen.
I might see a small puff of smoke and a smoke-ring just before they pass the shed. Indications of en enginefailure. I also see the wings tilt briefly - a few degrees - towards left. Correct procedure after enginefailure is to tilt the wings about 3 degrees toward the engine that is still running. I also see them climb at a - it seems - too high angle for the actual conditions if engine has failed. That will kill the nescessary engineoutspeed in a few seconds and be hard to recover from. If - and I say if - they in this stressed situation managed to shot down the wrong engine following the engineout procedures the RAT would come out. That would probably preoccupy them so much they forget everything about gear and flaps.. It is a situation I believe most experienced 777 / 787 pilots would recognise as a possibility and would explain everything. But this is pure speculation. Lets wait and see what the investigation teams find out... https://www.aerotime.aero/articles/a...w-so-far-crash 3 users liked this post. |
EDML
2025-06-15T22:56:00 permalink Post: 11902933 |
Also there is no asymmetry visible in any of the videos. |
Capn Bloggs
2025-06-15T23:19:00 permalink Post: 11902951 |
Originally Posted by
Seven-Five
If - and I say if - they in this stressed situation managed to shot down the wrong engine following the engineout procedures...
Originally Posted by
EDML
Who would start the engine out procedure at just 100-200ft AGL? No airline teaches that and it doesn't have any advantage.
3 users liked this post. |
OldnGrounded
2025-06-15T23:55:00 permalink Post: 11902983 |
Ah, yes. Missed that. Thanks. But I have to assume (I know) that any responsible aviation engineers designing a system that can shut down both (all) engines simultaneously when the airplane is on the ground is going to want to make very sure that the airplane is on the ground.
But I'll check. |
Sailvi767
2025-06-16T00:11:00 permalink Post: 11902995 |
Experienced 777 driver. Have tried to solve the puzzle. Looked carefully at the video in this article many times - see below and use full screen.
I might see a small puff of smoke and a smoke-ring just before they pass the shed. Indications of en enginefailure. I also see the wings tilt briefly - a few degrees - towards left. Correct procedure after enginefailure is to tilt the wings about 3 degrees toward the engine that is still running. I also see them climb at a - it seems - too high angle for the actual conditions if engine has failed. That will kill the nescessary engineoutspeed in a few seconds and be hard to recover from. If - and I say if - they in this stressed situation managed to shot down the wrong engine following the engineout procedures the RAT would come out. That would probably preoccupy them so much they forget everything about gear and flaps.. It is a situation I believe most experienced 777 / 787 pilots would recognise as a possibility and would explain everything. But this is pure speculation. Lets wait and see what the investigation teams find out... https://www.aerotime.aero/articles/a...w-so-far-crash 4 users liked this post. |
Capn Bloggs
2025-06-16T01:18:00 permalink Post: 11903027 |
Originally Posted by
Seven-Five
I might see a small puff of smoke and a smoke-ring just before they pass the shed. Indications of en enginefailure. I also see the wings tilt briefly - a few degrees - towards left. Correct procedure after enginefailure is to tilt the wings about 3 degrees toward the engine that is still running. I also see them climb at a - it seems - too high angle for the actual conditions if engine has failed. That will kill the nescessary engineoutspeed in a few seconds and be hard to recover from. If - and I say if - they in this stressed situation managed to shot down the wrong engine following the engineout procedures the RAT would come out. That would probably preoccupy them so much they forget everything about gear and flaps.. It is a situation I believe most experienced 777 / 787 pilots would recognise as a possibility and would explain everything.
Originally Posted by
T28
In that poster's defense, you will find that they joined PPRuNe in 2002, and their original profile entry was 767.
The upgrade to 777 between then and now is within reason. Increasingly, the posts in this thread are becoming more ridiculous as time goes on. The hampsterwheel bearings will soon explode. IMO it should be locked. 6 users liked this post. |
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