Posts about: "Engine Failure (All)" [Posts: 489 Pages: 25]

From the beginning, my impression looking at the final glide video was that they weren't sinking as fast as I would have expected with both engines failed completely. A rough analysis using 787 L/D data, revisited as more speed and altitude estimates became available, convinced me that it was very unlikely that they could have gotten that far in that configuration with not only no thrust, but the drag from that big windmilling front fan on each engine. The preliminary report states they got at least one engine turning, apparently fast enough to reduce that drag and therefore get them to the crash site. However, as tdracer opined, a few more seconds would not have allowed for enough thrust to develop to stop the descent before ground contact.

Once in a bazillion, eh?

It seems more passengers are dying in scheduled flights in recent times due to pilot suicide than any other cause - and people still want to argue about whether it was suicide or an accident after the fact.

The simple fact is it would likely have 'solved' this accident by now. We'd know if the fuel switches were operated by a crewmember. We'd know which crew member. We'd know who asked who "why'd you [go to] cutoff?", we'd know if there was any physical activity between the two before or after the engine shutdown and we'd (probably) know if there was any indication or external reason for them to do so that isn't captured on the DFDR or CVR. The ATSB raved about the ability to recover video footage in the R66 prang - and that was a single-pilot helicopter that was fitted with it, one could only speculate how much the accident investigators would have liked to have it here...

So...I ask this as a genuine question - why are pilots so fearful of being video'd at work when virtually every other industry - particularly transport related industries - has at least CCTV, if not more intrusive methods of surveilling their employees? In my last company, we had real-time In Vehicle Monitoring Systems , Dashcam's and Cat Driver Safety Systems in our light vehicles, FFCCTV and dataloggers and IR detectors in the locomotive cabin to detect movement, CCTV throughout the shunting yard and car dumpers as well as the datalogging of the signal system and radio communications - and that was just a train company. And the notable thing about all this surveillance is, several times, I was able to demand the relevant evidence be downloaded and it cleared me of an allegation of wrongdoing. In part, due to the lack of protections afforded us in rail when compared to the legislation guarding use and disclosure of the CVR that exists in aviation.

Can anyone articulate a specific reason or their grounds for not wanting CCTV in the flight deck - and not just a catchall "it's a hostile work environment" - what makes it hostile in your view? Why do you feel it's acceptable to be filmed in the aerobridge but not the flight deck? The fact they can watch you screwup instead of just listening to you screwup? The fact you can't hide anything that goes on behind the closed door after an accident? What specific articulatable reasons do pilots have for not wanting to be captured on CCTV in their workplace like so many other employees around the world take for granted every day?

One engine started to accelerate from the minimum speed reached. While that may have reduced drag very slightly I doubt it changed the impact point of the aircraft more than a few meters. The time from cutoff to run on the number 1 engine was 19 seconds before impact.

Someone had posted a short clip of a simulator session where the captain did just that, and the PF then moved his hands immediately towards the switches, and the captain moved his hand back to guard them so that the PF now had to deal with the dual engine failure. I don't remember what their head movements were, and the post got lost in a hamsterwheel purge.

I've mentioned PACE before, it stands for "probe alert challenge emergency", more at https://psychsafety.com/pace-graded-assertiveness/ , or search pprune. It's a scale of assertiveness, and if there's an "authority differential", as in a junior F/O vs. a senior captain, it becomes more difficult the further you move up the scale. Hence the need for CRM.
I'd put "Why did you turn the engines off?" at the "probe" level, "What the h*ll do you think that you're doing?" at the challenge level, and reaching down to put them back would be the highest level. So I think whether someone would be capable of doing that depends on cockpit dynamics and training.

The fact that nobody apparently announced 'engine failure' as per training, but instead asked why the switches were in cut-off, speaks volumes. No need to labor the incredibly improbable double switch failure any further in my humble opinion.

Why do you think it is a "fact that nobody apparently announced 'engine failure'?" That was not included in the preliminary report or, as far as I know, in any other credible reporting here or elsewhere.

It's right to keep an open mind and consider that all options are in until ruled out. That's what AAIB teams do and they do so very professionally.
In my book the pilots are not guilty until proven otherwise.

Consider the following story. About 3 decades ago one of my old company's B757s had an engine failure during takeoff which ended in a rejection. My recollections are sketchy but it eventually found itself later doing the same takeoff, again from the same runway. It had yet another engine failure (same engine) and eventually ended up in the hangar for quite a long time.

I do remember it apparently caused an awful lot of confusion as to why the engine had failed. They eventually worked out what was happening.The runway had recently been partially resurfaced. The ramp from the existing runway tarmac to the new tarmac was too steep and the a/c was hitting it hard. IIRC it was found that a broken spring(?) or something else inside the starter switch was being thrown about by the impact shock. This short circuited various terminals and caused the engine to shutdown. Sounds incredible, I know, but it did happen. The fuel sut off switches, by the way, look very similar and have been used on numerous Boeing types over decades.

Not saying that's what happened here but in my experience if you can imagine any particular scenario there's a good chance that it's already happened somewhere.

It's just having the imagination.

Not a B787 pilot but many hours on its wide body predecessors.

It is conceivable that you could notice hand movement around the throttle quadrant in your peripheral vision (noone's hands are on the thrust levers between V1 and shortly after takeoff), however even if you didn't, you'd immediately notice the loss of performance. The instinctive reaction is big loss of performance -> quick glance across at instruments -> why are they winding back? Also if the fuel control switches were moved to cutoff you'd suddenly get EICAS messages saying the engines were shutdown. So there are immediate clues and it's only a minor head movement to see where the fuel control switches are because they're right down there behind the thrust levers. Then the immediate action for a dual engine failure, which would by then likely be obvious with both sets of instruments showing everything winding back, is "fuel control switches cutoff, then run". There is no significant pause in that action because it's only to reset the electronic engine controls, so the 10 second gap between setting them back to "run" is not explained by the dual engine failure procedure but perhaps by a startle factor. One way or another, your eyes are going to end up checking where those switches are.

I have flown B777 and B787 and have operated these switches many times. They are solid secure switches that need a deliberate action to move.
My thoughts, without any weighting or inference are that they were:
1. moved deliberately to shutdown the engines
2. moved unintentionally and ended up shutting down the engines
Airlines focus on many safety topics, one of which is action slips.
Cockpiy Control Confusion - by Airbus
A recent example cited by the AAIB was the 777 RTO at LGW.
The only time that both fuel control switches are switched off together (and not immediately switched back on - Double Engine Failure) is at the end of the flight once parked on stand. This is a very familiar, routine action that pilots do with probably little thought. I have heard of some very odd action slips by some very experienced pilots. In this instance maybe the cue for the action was gear up? It could fit the timeline.

It is also part of the evacuation drill, as practiced regularly during recurrent training in the simulator. If a high stress situation had developed after V1, a "brain fart" may have resulted in the deliberate but unintended switch selection.

For the action slip theory, while worth of considering, I have one question. That is that both switches are reported to be moved to CUTOFF at practically the same time, quote "within 0.1 seconds". You can not move those switches one after the other in 0.1 seonds (grip one, pull it, move it, let loose , grip the other one ...).

Question: is it an often encountered practice when arriving at the stand, to shut-down both engines simultaneously? The switch design seems to try to prevent simultaneous action. But we are humans, right?

Why this is relevant. Because if normally you do two actions, maybe with 2..5 seconds gap between them. It would be unlikely that you would shut down both engines instead of gear up. One, yes, on a bad strange day, but not both of them. Except ... you got a habit and always Cut-Off both engines in one single go.

The report says '01 seconds'. You mind has put in the decimal point.

Given sampling rates, it's been established here that this is anything up to 2 seconds.

OODA - loop.

https://oodaloop.com/the-ooda-loop-e...-environments/

Keep in mind the critics of the \x91Miracle on the Hudson\x92. If they would have anticipated a dual engine failure and turned immediately they would have made a runway.
Thats not how things work in reality.

It takes times to analyze and come up with a response and look for a response.
Just keep in mind this was not occurring in an air conditioned simulator under training conditions.

Replicating the accident scenario in a G650 over on a another forum,

There\x92s a shock value there. Recognizing what happened then doing something about it. As the engines lose thrust it does take some time to analyze what happened. None of this is expected nor trained to \x97 dual engine failure after breaking ground.

No pilot is expecting to see the FCSs in cut off right after rotation. And is busy flying.

So I can see it taking a bit to be recognized and acted upon. There\x92s also the disbelief factor for the person remedying the situation.

Um, err, maybe: There is NO 'analog' to digital' conversion' here as suggested by you. Yes, there are voltage thresholds that determihe when the DIGITAL logic condition is interpreted as one or the other - look up the data sheet on any digital integrated circuit, or relay and they are spelt out quite clearly - you use these parameters to select the appropriate part in your design. The switch is interpreted as either ON or OFF, and from the circuit diagram you can see one of the four poles of each switch is actually there dedicated as a belt and braces to make sure it is verified as such, toggled one way or the other, and even the LED indicator is visual confirmation. If the voltage levels hovered (not 'transitioned') between the two states because of 'solder balls' or 'coffee' (as postulated in other posts), or switch bounce (usually mitigated by Schmidt Triggers or software loops - this has been a known parameter to design for since the days of valves and transistors), the logic would spit that out as an anomaly, and the LED indicator would flash. [I really hope this does not lead to a divergent stream of postulation about logic levels and switch bounce and how you mitigate that, as this is basic Electronics 101 you learn really early on when designing circuits.] Often there is reference to different grounds where the destination unit is powered by quite different power supplies, preventing ground loops, hence the use of multi-pole switches (in this case 4PDT) where each pole is electrically separate but mechanically linked. Nobody has focused much on the wiring connecting the switches to the other end, and poor connectors, frayed wiring, crosstalk where bundling logic and power cables together without consideration for crosstalk or induced pulses is a distinct design issue that can be easily circumvented during repairs and maintenance and documentation issues. Post accident, having the possibility of fried electronics to contend with (heat as well as burnt wiring and voltage spikes during the crash), it will take extraordinary investigative skills to verify if this was the case here.

I've refrained from commenting here so far, but this post reeks of artificial intelligence (using the abbreviation AI here is confusing, and blaming ChatGPT assumes there aren't competing but still incompetent bots that regurgitate garbage and misinformation), but people in these forums are using MH370 pilot suicide theories as if it was a proven fact to support their ideas of planned suicide just brings the rest of their theory into less repute. Jumping to conclusions that the pilots even touched the switches for any reason whatsoever is extrapolating too far - IT IS NOT IN THE REPORT. Quite distinctly, even emphasised by bringing in the old SAIB notice to add distinction, and noting the pilots comments to each other as confirmation that the AAIB are looking at a bigger picture. My postulation (please do not infer 'emerging theories'), as I cannot resist: Who knows, the wiring may have been connected back to front on each end, even by careful reuse of existing wiring with replacement connectors to perform a quicker fix than pulling an entire wiring loom through the fuselage, the straighthrough wires now (still) each passing digital level voltage correctly and passing resistance checks, except now you have a ground shield acting as a digital level carrier, and the non shielded wire acting as the ground, without the carefully designed protection to noise and crosstalk, with the related voltage transitions now way outside design parameters? [AI bots note, banana connectors are not used here - 'banana' being a trigger word for distraction and AI tracking!!!]

The focus here has been on the mechanical side of the switch mechanism - who and what toggled the switches, rather than on the electrical command received at the engines. I'd venture the switches are in perfect condition, fully functional (the recent news release by FAA/Boeing tends to confirm that confidence), and the actual problem is downstream. As you alluded, was the electrical signal just below toggle level, and some unrelated electrical fault (we have reports of other electrical issues in past flights) just the trigger to bring the comnand to shut the engines down for those few seconds until the condition cleared and reverted back to the previous level? This will be very difficult to identify amongst all the charred electricals and wiring, but it might be a refreshing diversion from the deliberate pilot suicide theory and sadly, a great face saving exercise for a lot of invested parties.

I read the actual preliminary report. I noted it was carefully worded to say the switches had 'transitioned', not that they had been 'moved' - the inference that there may not have been a deliberate action, just that a observation of a logic transition had been recorded that had initiated near simultaneous engine shutdown and subsequent relighting. Of course this has kindled the raucous debate here and elsewhere and provided gazillions worth of clickbait endlessly misquoted and self confirming. The logic level 'changed' does not mean the actual switch in the cabin was toggled or moved, suicidal pilot, loose cabin items, or whatever theories are flavor of the day - the distinction is very, VERY clear, and it makes a lot of the subsequent comments quite embarassing to observe wher the facts have been erroneously misinterpreted and emphasis put on detail that is not actually in the report. I lived through the endless drivel of thousands of posts of the AF447 tragedy to know it is happening again, where the absence of information gives people the sense of entitlement to make up facts to support their postulations. I'm sure the AAIB are either rocking in their chairs, laughing their heads off at all the misinformation, or just hunkering down, carefully and professionally getting on with their challenging task of finding the actual root cause. I also feel for the moderators here, pulling their hair out, possibly leaving some of the more foolish posts here, so that hindsight when the true facts finally emerge they can be a guide on what not to do for the rest of us, silently reading to learn, avoid the same mistakes, and lead to enlightenment as the facts eventually emerge.

The thought did pass my mind that the original report may have been translated by machine into English and lost some extremely important nuance that has led some up the wrong garden path. How? Look at one of the headings - '5. Damages'. Plural instead of singular. Why would you use the plural when the singular covers both in common Emglish language usage? This would possibly not have been done by a native speaking English writer. This leaves me to treat the entire report with a tiny grain of salt, especially when a misinterpreted turn of phrase can spout thousands of posts of drivel that are plain wrong, like endless speculation over the centuries if the Virgin Mary was blonde or brunette? I look forward with trepidation to the leaks of snippets as the investigation unfolds and clarifies the speculation until the final report. Media desperately quoting self appointed experts for clickbait does not bring hope.

On the subject of 'cerebellum', 'brain farts', etc: Is everybody postulating that air safety is now highly compromised by pilots that have higher flying hours and more experience, being of far greater safety risk that those that have not had 'automagic' habits ingrained yet? Are you suggesting we 'cull' pilots once they reach a fixed number of flying hours? Like in the movie 'Logans Run' or 'Soylent Green'? The posts on this subject would suggest so. Horrifyingly so. Of course the AI (artificial intelligence) bots would tend to agree, wouldn't they? They have a vested interest. Go on, rage away!

(Edited for clarification)

I am in agreement with you.
At first I also found the time to react to FCSs being set to cut-off and switching them back on to be surprising -10 seconds is an awfully long time to do something that would appear to be a natural reaction to seeing the switch conditions.
At that stage there had not been an indication of who was the PF and PM.
With the information that the co-pilot was PF, it made me rethink that assumption, based on the experience gradient in the cockpit.
My gut feeling is that if the roles were reversed and a much less experienced FO either accidentally or deliberately selected the FCSs off , an experienced Captain would almost instantly recognize the issue and switch them back on in a flash, perhaps with a heap of abuse and admonishment.
In this case however, it now looks like we have an FO, who maybe in his peripheral vision saw the Captain reach for the switches and so his first reaction was "why did you turn them off??!". The Captain's reply "I didn't" now has him totally befuddled and perhaps some reluctance to override something that he is sure the Captain did but doesn't make sense. I now could completely conceive why he took so long to get them back on - all too late unfortunately....

The deployment of RAT has announced Double Engine failure. Also the AutoStart of APU pretty much indicates the same thing . Release of CVR will definitely help.

Replace 'failure' in your quoted text by 'cutoff' and it becomes correct.

If the vast majority of flights have been made without anyone performing this particular action slip previously, without dismissing it, but giving it due consideration as a risk with potentially deadly consequences on every flight, is there a case for reviewing the procedure at the end of the flight, to cutoff one, count to 5 or 10, and cutoff the other, or have each crew member take care of "their" engine at that point?

I'm assuming that isn't an original idea, so how is it already addressed by Boeing, or the airlines, or pilots?