Posts about: "Condolences" [Posts: 21 Pages: 2]

Please all... let's get more facts and data before unwarranted speculation about cause or culpability.

That's especially pertinent about questionable aspects like flap extensions used for takeoff, temperature effects, limited runway distance, and other likely irrelevant circumstances.

The "bang", Mayday call, potential RAT deployment, and high alpha touchdown may prove significant, ....if and only if they are later verified by accident investigation.

It is most inappropriate to yet for any professional aviators be inferring any flight crew, airline, or OEM connections whatsoever. Only sympathy and aid for the crew, passengers, families, airline, and those impacted by this tragic crash, and support to the accident investigators, ....should be in our thoughts and prayers at this point.

Condolences to all the people who have lost loved ones:

I have a question about that: As the plane would have been half fueled (say 50t), a full flight and full luggage etc - and if it didn't have enough speed for - say no flaps, short takeoff, pulled up before V1 - and assuming both engines were 'ok':

Aren't aircraft nowadays require only one engine for a takeoff in an emergency (one assumes that would be a in fully loaded configuration)...?

If so, then surely two fully good engines should have no problem, particularly when it's taken off already...?

as discussed above it\x92s very unlikely this aircraft was fully fueled since the flight is far less than its maximum range.

Fully fueled would be a bit over 100T

My sympathy (and empathy!) is entirely with the Mods - Like some, I have been here for almost 23 years watching these same types of uninformed contributions.

Easy does it, eh?…There are no workable methods to “create two parallel threads”.
If you want a free and open forum, just give the Mods a break, and set anyone who apparently doesn’t know their stuff but chooses to post their nonsense anyway, to Ignore.

That’s what that tool is for, and it keeps one’s own reading of serious and informed contributions within reason.
Q.E.D.?

PJ2

Firstly, condolences to all those involved.

Secondly the above is a load of rubbish, as someone who also 'trains and checks' pilots and also has many years of Safety Investigation within large airlines it is a semi regular occurrence to depart with incorrect or no data.

Tiger took off in Sydney with NO data in the FMGC,
Singapore had a tail strike in AKL after inserting the ZFW as the TOW
Emirates almost crashed in MEL for similar reasons.

Not saying that this happened here

Air NZ a few years ago almost put a 787 in the water out of Rarotonga as they had 100' in the FCU, took off, engaged autopilot and the aircraft pitched down and thrust came off, pilots recovered it at 60agl.
Emirates has done similar, so these things happen.

Clearly we don't know what happened here but I think it fair to assume it went wrong at rotate given the gear stayed down which would suggest a distraction at that point.

This aircraft has got airborne well within the requirements of FAR 25 under which it was certified. It has over 1250m ahead of it passing around 35' based on the video from behind, so the FMC data was not incorrect, the thrust up until after TO was not incorrect, and the CG is not out of range, the time to rotate is within expected range, and the attitude at liftoff is not excessive, the plane is not heavier than expected. This is not Emirates, Tiger or SQ, it may have a resemblance to AFR out of Nigeria, or ANZ out of Raro, or UAL out of Hilo. Unlikely but there are similarities.

A low altitude in the MCP can become pretty interesting, as will a TAT probe failure to the ATR thrust limit. Both cases will have the thrust levers moving back rapidly. There is no obvious failure of the engines at this point save the question that the RAT may be deployed. A transient electrical fault tripping the logic for the RAT is hard to imagine, but that would possibly end up with an ATR fault and power coming back to idle. Fuel contamination is not impossible, but it is improbable, the engines would have been on their TO configuration from the engine start, and the taxi and turnaround takes enough time to flush the fuel lines, being longer than the selected tank sampling time that sits behind the SOPs. Boeing aircraft are easier for the crew to detect anomalous thrust commands compared to the Airbus, however, if the RAT is out... then more was happening.

The flaps are in the correct position, we are looking at a time critical failure for the crew, they appear to have around 10 seconds between onset and impact, and they have rotated the aircraft in the later stages, as any reasonable pilot would do, and that certainly does not indicate a crew initiated problem on the available information. Unlawful interference is unlikely, given the RT calls that have been made.

The IDGA AAIB is not known for rapid response, this event is of international importance, it appears that it is being treated as such by the authorities involved. The EAFRs on the 787 will tell all soon, and we need that information, this is a globally important aircraft type.



Such a terrible shame, condolences to all. It looks inexplicable from the CCTV.

Seems time for a visual evidence review.

There seems to be a RAT theory based on a hyper zoomed artifact and someone showing a RAT deployed on a different airframe. Not convinced about that, you might get a similar artifact from a belly antenna. The noise? CCTV doesn\x92t have noise and the other pictures I saw were from a car in traffic.

Others are are saying it climbed to 500\x92, not sure about that, the highest I have seen visually is less than 300\x92, QNH vs. QFE I suspect.

Flaps vs. Gear definitely a possibility and the AoA was increasing particularly after the descent started.

Double EF (If RAT deployment not a red herring) Fuel contamination? Would have to be deliberate as no other aircraft affected, unlikely. Maintenance or crew error, possible unlikely. Bird strike, no evidence.

MTOW error possible but it seemed to take off fine so no reason for the return to the ground.

What about the bang the survivor heard? I suspect you can treat the evidence of anyone involved in an air crash with a pinch of salt. Order of events are often out of sequence even when talking to trained observers in less stressful situations

MCP mis-setting to 100\x92. Engage AP early, often seen, thrust immediately commands to idle by ATHR, starts to sink, extreme startle and forget gear because it appears like a double EF.

I know where my money is but only time will tell, if they get the Black Boxes in good condition, the factual statement should clear it up quickly.

Your MCP theory sounds feasible but doesn\x92t stand up to Boeing VNAV engagement logic (assuming it\x92s typical Boeing) which would mean at 400\x92 the aircraft would still try to maintain V2. It just might pitch the wrong way. Interestingly, the AT system has caused more accidents on the Boeing than the Bus. Much to everyone\x92s surprise considering the TL\x92s don\x92t move on the Bus..

There isn't enough clarity on numerous issues, and without answers to the following, zero conclusions can be made as to a possible cause. This is definitely one that could go in numerous directions. Anyone claiming to have the definitive answers must have the FDR data, and I'm assuming that shouldn't take too long to be located and analysed.

1a. Were flaps deployed at start of take off roll?
1b. Were flaps retracted coinciding with climb rate reduction?
2. Did the RAT definitely deploy? The videos are grainy low quality. AI improvement surely isn't reliable.
3. If the RAT deployed, would that indicate complete power loss?
4. Was there any other audio indicating thrust loss or variations during departure?
5. Can we confirm the pilot Mayday indicating thrust loss? If so, that needs investigation as a first priority. The pilot was telling us the cause. Unless we have alternative information he should be believed.
6. Why was the gear not retracted? Distraction, hydraulic failure, flap instead of gear, intentionally, the possibilities are endless.
7. If complete thrust loss occurred, other than a severe fuel issue, what could cause simultaneous flameout? That would be almost unimaginable, yet this is what the pilot allergy said happened. It would have massive ramifications if that gets confirmed.

I don't think the video clips we have are clear enough to say anything at all at this stage. Flaps are hard to see on 787 imo for departure settings. All I can say is it appeared to climb well in the first seconds, then coinciding with the point that gear would usually be retracted, lift appears to very quickly be lost. That indicates sudden speed loss, or lift loss. Speed loss would be thrust, lift loss would be flap retraction if thrust was still available.

The pilot allegedly reported thrust loss, that should be highest on the list of causes imo. In the case of double engine failure without any apparent outside influence visible on videos, that would be quite something for investigators to fathom.

I don't know if anyone has data to show speed trend at the point the aircraft starts to descend, or a better audio for thrust variations at that point. I'm guessing that the update frequency on FR24 would be too slow to show that sudden change at the highest point achieved.

We'll have the answers soon enough, all I can say is there appears to be no clear answers here without the data recorders or clear improved information. Indeed no conclusions whatsoever can be made as to crew actions either.

RIP crew and passengers, condolences to the families.

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.

Hard to imagine if that mistake was made he\x92d get on the radio saying engines losing power with out pushing levers up first ? What ever happened had guy in left seat stunned ? My opinion only , if he was a training Capt he , like most guys in the left keep a good watch on where hands go . If an incorrect weight, chances are he\x92d know on runway and thrust to TOGA , those engines appear to be along way off producing thrust . If flap was raised by mistake , flap can be lowered just as quick . He\x92d not be on radio saying thrust decreasing while looking at flap up . If miss set alt hold he\x92d be calling modes and selecting higher altitude and changing climb mode thinking he\x92s got to remember to write a report on arrival . If engines turned off deliberately!! Big If , no need for radio calls , turn engines back on and protect them and try isolating flight controls, if possible .

If RAT out ??? That tells a lot .

Not long to wait now ?

condolences to family\x92s and loved ones !

There should not be a max pre-start EGT limit in-flight - that should only occur on the ground for a pilot-initiated Autostart where the starting EGT redlines are lower than for in-flight.

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.

Firstly, condolences to all those involved.

Secondly the above is a load of rubbish, as someone who also 'trains and checks' pilots and also has many years of Safety Investigation within large airlines it is a semi regular occurrence to depart with incorrect or no data.

Tiger took off in Sydney with NO data in the FMGC,
Singapore had a tail strike in AKL after inserting the ZFW as the TOW
Emirates almost crashed in MEL for similar reasons.

Not saying that this happened here

Air NZ a few years ago almost put a 787 in the water out of Rarotonga as they had 100' in the FCU, took off, engaged autopilot and the aircraft pitched down and thrust came off, pilots recovered it at 60agl.
Emirates has done similar, so these things happen.

Clearly we don't know what happened here but I think it fair to assume it went wrong at rotate given the gear stayed down which would suggest a distraction at that point.

I preface this post by acknowledging all the previous posts in this, and the now-closed thread, about the TCMA, in particular the excellent posts by tdracer. (Ditto the noise analyses by Kraftstoffvondesibel and First Principal.)

I also note that the primary source of the information on which I’m basing my post is the content of Boeing’s patent application which, of course, does not contain any of the actual wiring diagrams or modification details of the TCMA, even assuming it has been implemented. (I understand from the now-closed thread, that there is an unresolved question as to whether a petition for an exemption from the TCMA requirement had been successful.)

The point of my post is to get other’s thoughts on one of the design principles of the TCMA system proposed in the patent application.

The ostensibly simple and elegant concept is described in the schematic of the system at figure 1 of the patent application. A copy of figure 1 is below.

The TCMA is the part of the schematic inside the dotted box numbered 16 , sitting with the EEC (others would call it the FADEC) in the solid box numbered 18 .

The heart of the TCMA comprises two switch relays, numbered 22 and 28 in the schematic, wired in series. Each of those switch relays is controlled by its own, dedicated engine control malfunction software, identified as the blobs numbered 130 . (The patent application identifies component 34 as a dedicated processor and 32 as the diode connected to the switch relays, but that is evidently a mistake. Component 34 is the diode and I can’t find a component number 32 anywhere in the schematics.)

Each relay switch and its controlling software is described as a ‘channel’, one A and one B. Both channels run continuously, monitoring throttle position (36 in the schematic) versus engine data fed from ARINC data bus lines (46 in the schematic) and “dedicated input sensors” not shown in the schematic. Those sensors presumably detect things like weight on wheels and perhaps RADALT.

This design is said to achieve redundancy, because if only one ‘channel’ detects the engine is producing excessive thrust while the throttle is set to idle, that channel will set its switch relay to CUTOFF and that is enough to change the state of the high pressure fuel shut off valve (58 in the schematic). No more motion lotion. In the words of the patent application: Both channels are “always actively monitoring engine function and independently have the capability of shutting down the engine.”

That arrangement wrinkled my crusty old avtech brow. In my mind – and this is why I’m seeking other’s thoughts – the advantage of redundancy arising from the two channels, either or both of which can shut the engine down, is not without risk. If it is possible for one of the channels to have some ‘glitch’ or hardware failure such that it does not detect an actual out of envelope condition justifying immediate shut down, with the other channel detecting the condition and shutting the engine down, it inexorably follows – does it not – that it is possible for one (or both) of the channels to have a ‘glitch’ or hardware failure that results in a shut down when there is no out of envelope condition?

Further, even if there are completely separate, duplicated sensors telling each channel things like the position of the throttle and whether or not there is weight on wheels, there remains the possibility of a combination of sensor failures/disconnects resulting in one channel being ‘convinced’ that an out of envelope condition exists, with a consequential cutoff of fuel to the engine.

I of course acknowledge the valid observations made about the remote probabilities of these kinds of glitches and failures.

I’ve heard rumours that there was much resistance to the mandating of TCMA systems. Having seen many, many strange faults caused by random shorts, open circuits, liquid ingress and other foreign objects, I can understand why there was that resistance. Every time you add something to a system and that added thing has electronic components and software and electrical connections and data inputs, you add risk of that thing malfunctioning or working perfectly but with erroneous inputs. In this case, there are effectively two added new things: two channels, each one of which has the ability to shut off the motion lotion to the engine to which they are strapped.

I make no comment on whether TCMA systems, if fitted, have anything to do with this tragedy.

My profound condolences to the families and friends of those killed or injured. My thoughts also go out to the many people who will be agonising over the potential causes and responsibility for it. And thanks to those who are working out the causes.

...

If this happens, and hasn\x92t yet led to a fatal accident, is it possible over say incorrect or no data could lead to a fatal accident (not saying it happened here).

Could incorrect or no data coupled with other issues (eg hydraulics, electrical or engine failure) lead to a situation that might have been recoverable with the correct data being unrecoverable?

Think about this accident from 100,000 feet. In other words, DON\x92T think about the specific root cause. We have almost no factual information to ponder at the moment but we can still ask a larger question: How did an experienced crew in a modern aircraft find themselves in a situation from which there apparently was no escape? Given the redundancies, fault tolerances, crew training, and engineering and operational controls present in modern aviation, how could it be that they happily took off in an airplane and flew it into an unsurvivable event just moments later?

This isn\x92t the first one either. On February 9, 2024 a Challenger 600 manuevering to final at Naples FL, (APF) lost both engines simultaneously and crashed on a highway short of the runway. The NTSB final report isn\x92t out yet so we don\x92t know that cause either, but the situation was the same. SOMEhow, a highly experienced crew found themselves in a situation from which there was apparently no escape. Whatever the cause was, how did it go un-detected until it produced an accident? (It\x92s NTSB accident number ERA24FA110. You can find that thread on PPRUNE by searching on Challenger 600. The preliminary NTSB report contains interesting readouts from the FDR. Yes, they lost both fans simultaneously.) I\x92m not suggesting these two accidents have related causes, I\x92m only observing that both crews apparently had no way out.

I\x92m asking, \x93Whatever the flaw was that initiated these events, how did it remain un-known *until* it produced an accident?\x94 We test and re-test modern aircraft for every imaginable failure mode during the design, certification, and production process. We train and re-train techs, mechanics, flight crew, and everybody else that touches the airplane to be sure a high level of performance and safety is not compromised. Think bigger. Think about \x93the system\x94 as a whole. Apparently the system missed something. What are we not seeing?

My condolences to all who were lost. Please keep in mind that except by the grace of God it could have been any one of us on that terrible day.

NASA retired, licensed since 1971.

I didn't read that thread, but having flown the aircraft (challenger 600 type), I believe the consensus is that the Captain reaching underneath the thrust levers to actuate the flaps can (and has) resulted in the "triggers" on the back of the thrust levers being engaged- if this is done while the FO is bringing the thrust to idle, it can result in going below the idle stop to cutoff. In other words, the engines were inadvertently shut down.

But I agree that the complete, simultaneous loss of thrust on both engines has to be an astronomical probability, and the cause is going to be interesting to say the least.

I also agree that any one of us could be put in a horrible position within seconds that would be very hard to recover from- the older I get and the more hours I spend in the air, this starts to spend more time in one's consciousness, unfortunately.

BTW calling the crew " highly experienced" is a bit of a stretch IMO, the Captain certainly was, but 1100 hours isn't even enough for an ATP in most countries. For all we know it was not a factor, of course.

PS, what is an SLF??

The generic version in your drawing has the centre position, whereas the version used on the 787 (4TL837-3D) has centre lockout. This photo shows the switch. You can see it is pretty easy to not place it in the locked positions. With this design of switch the cam on the toggle will eventually wear away.

this isn\x92t the type of switch fitted to the 787 as a fuel control switch, totally irrelevant but has generated yet more nonsense. The switches are spring loaded (or so it feels) in addition to having a massive block to prevent inadvertent operation in either direction. Anyone suggesting they could be accidentally \x93knocked off\x94 is so clueless about their operation it\x92s actually painful to rebut