Posts about: "Engine Failure (All)" [Posts: 493 Pages: 25]

Lonewolf_50
June 30, 2025, 13:08:00 GMT
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Post: 11913613
Originally Posted by The Brigadier
We know that the right-hand GEnx-1B was removed for overhaul and re-installed in March 2025 so it was at “zero time” and zero cycles, meaning a performance asymmetry that the FADEC would have to manage every time maximum thrust is selected. If the old engine was still on the pre-2021 EEC build while the fresh engine carried the post-Service Bulletin software/hardware, a dual “commanded rollback” is plausible.
A latent fault on one channel with the mid-life core can prompt the other engine to match thrust to maintain symmetry, leading to dual rollback.
Then why didn't that happen on the previous flight from Deli to Ahmedabad, or any of the previous flights since that engine install in March?
Originally Posted by silverelise
He also confirmed that all the data from the recorders has been downloaded and is being processed by the Indian AAIB, no boxes have been sent abroad.
The 30 day deadline for the preliminary report is July 12th.
Thanks for the update, and in particular that bolded bit.
Originally Posted by the linked article
Investigators still haven’t ruled out the possibility of sabotage being behind the Air India crash in Ahmedabad earlier this month that killed 274 people , according to India’s aviation minister. The Aircraft Accident Investigation Bureau (AAIB) has confirmed that the aircraft’s flight recorders – known as black boxes – will not be sent outside the country for assessment and will be analysed by the agency, said Murlidhar Mohol, the minister of state for civil aviation.l

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skwdenyer
June 30, 2025, 14:04:00 GMT
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Post: 11913652
Posters may like to read this old (2016) pprune thread on 787 engine failure procedures: 787 engine failure procedure

Some interesting comments about how a combination of ATM and derate can lead to some pretty surprisingly poor outcomes, coupled with Boeing advice not to advance thrust levers or engage TOGA.

(edited for poor spelling)

Last edited by skwdenyer; 30th June 2025 at 14:40 .

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adfad
June 30, 2025, 15:49:00 GMT
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Post: 11913716
Originally Posted by silverelise
India's Minister of State for Civil Aviation appears to be confirming in this interview that the cause of the accident was a dual engine failure. Which is, I think, the first vaguely official confirmation of what happened that has been released? He also confirmed that all the data from the recorders has been downloaded and is being processed by the Indian AAIB, no boxes have been sent abroad.
The 30 day deadline for the preliminary report is July 12th.
It's hard to find a full and reliable translation of his statement but here is another snippet from Yahoo (I can't post links sorry)

The minister called the crash a \x93rare case\x94 and, referring to claims by veteran pilots and experts that a dual-engine failure may have led to the crash, said: \x93It has never happened that both engines have shut down together.\x94 \x93Once the report comes, we will be able to ascertain if it was an engine problem or fuel supply issue or why both engines had stopped functioning.
I think it's very important to define "engine failure" vs e.g., reduced thrust - BA38 for example was described as "restricted fuel flow when thrust was demanded" and there was no evidence of engine driven generator power stopping as the engines were still running at idle at impact. It's pretty clear from the available evidence that Air India lost electrical power within 20 seconds of leaving the ground, and based on the landing gear orientation theories that time may be significantly shorter <10 seconds.

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Capn Bloggs
June 30, 2025, 16:26:00 GMT
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Post: 11913745
Richard Godfrey has completely ignored that fact that the speed was reducing all the way down the descent. He has hypothesised a steady descent angle at around 3.5:1 and therefore concluded that one engine had stopped and the other was on ~10,000lb of thrust because, at the initial speed they needed that thrust to counter the drag. But the AOA clearly increases markedly as the aircraft approaches the ground, which means that the speed was reducing significantly.

As for statements such as:
One Engine Inoperative (OEI) just before take-off(Assumption).
​​​​​​​The Take-Off Speed at rotation is estimated at 160 KIAS (167 KTAS, 170 GS), which is higher than normal and expected in an assumed OEI take-off.
​​​​​​​The rotation point requires a runway ground roll of 2,540 m, which is longer than normal due to an assumed OEI take-off.
​​​​​​​The climb gradient is estimated at 5.09%, which is slightly above the normal range of 3% to 4%at TOGA for a Boeing 787-8, but within limits
​​​​​​​True airspeed was under-indicated due to low density, in other words the aircraft was moving faster through the air than the airspeed indicator showed, because there were fewer air molecules hitting the pitot tube in the hot, thin air
​​​​​​​The aircraft peaked early, then levelled off and started descending while passing over obstacles. It barely cleared Obstacle B by ~50 feet, which is tight, but sufficient. This explains the visibly profile in video and supports the notion of degraded climb due to hot/high conditions, heavyweight, and limited thrust margin
They make me take that whole spiel with a grain of salt.

In a nutshell, he's saying they had an engine failure before rotation, then got all the way up to 300-odd feet (following what looked to me like an initially standard low-angle/flat 787 takeoff, then ran out of puff and crashed with the other engine running at 15-18% Thrust.

Pure speculation aka WAG.

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87guy
June 30, 2025, 16:32:00 GMT
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Post: 11913751
Originally Posted by Capn Bloggs
Richard Godfrey has completely ignored that fact that the speed was reducing all the way down the descent. He has hypothesised a steady descent angle at around 3.5:1 and therefore concluded that one engine had stopped and the other was on ~10,000lb of thrust because, at the initial speed they needed that thrust to counter the drag. But the AOA clearly increases markedly as the aircraft approaches the ground, which means that the speed was reducing significantly.

As for statements such as:






They make me take that whole spiel with a grain of salt.

In a nutshell, he's saying they had an engine failure before rotation, then got all the way up to 300-odd feet (following what looked to me like an initially standard low-angle/flat 787 takeoff, then ran out of puff and crashed with the other engine running at 15-18% Thrust.

Pure speculation aka WAG.
I agree 100% with your last sentence.

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Sailvi767
June 30, 2025, 18:57:00 GMT
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Post: 11913849
Originally Posted by Abbas Ibn Firnas
I found descriptions on the systems of the 787 were easily discovered online, and while I have no hands-on experience of aircraft related matters, I do have experience in wider electrical theory and maintenance.

THRUST Asymmetry PROTECTION.
"For an engine-out condition, Thrust Asymmetry Protection (TAP) reduces thrust on the operating engine to ensure there is sufficient rudder for directional control. TAP reduces thrust when the airspeed decreases below approximately V2 on a takeoff or below approximately VREF on a go-around. Once speed is increased above V2/VREF, TAP increases thrust."

From what we know so far, it does seem the engines were not producing sufficient thrust, during a period when it would also be crucial to maintain electrical output for the electro-hydraulic systems and critical electrical loads.

Reduced electrical output could explain the failure of the gear to complete retraction, maybe caused by a generator failing at the worst possible moment.

If there was an EFATO, the ability of the remaining generators to provide sufficient power might become questionable, as is highlighted with the load shedding system.

Other features which are unique to the 787 could be contributing factors in explaining the accident.

It is known the 787 will generally employ an extended take-off roll, and a relatively higher V1 and Vr, and also climb out less steeply than other aircraft. Using more of the runway would reduce the margin for aborted take offs.

With the evident lack of thrust early in the climb out, and failure to retract the gear, if V2 had not been maintained, the TAP system would have reduced thrust even further. Manually increasing thrust will be inhibited.






None of the above makes any sense. There are excellent videos of the takeoff. The aircraft was rock solid in yaw. The takeoff roll and rotation appear normal. Had the flaps been up they would have had a tail strike before getting airborne. The videos show a normal takeoff roll, normal rotation and normal initial climb. At some point below 200 feet AGL all thrust is lost. Here is a video of what a single engine failure looks like before reaching acceleration height. Note also how the wing looks when it reaches about the same distance the Air India video is shot from. At flaps five they appear up.

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GroundedSpanner
June 30, 2025, 21:18:00 GMT
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Post: 11913900
Originally Posted by Sailvi767
It would go against every aspect of training for a professional crew to deploy the rat below 400 feet. Further if you put 100 crewmembers in a simulator on takeoff and said deploy the rat manually I would bet not a single crew member could find the rat deploy switch and activate it in under 5 seconds and maybe 2 or 3 in 10 seconds.
Yes, but The RAT doesn't have to be deployed manually.
It can auto-deploy in a significant electrical failure.
The theory I'm working is that, given the configuration of the aircraft, if there is a significant electrical failure (sufficient for the RAT to auto-deploy). The aircraft fuel pumps are lost. Approx. 7ish seconds after those fuel pumps are lost (if the engines are at TOGA), the fuel being received by the engines is arriving from a different source, a potentially contaminated source. I believe that the engine failure is a secondary result of the power loss (with specific circumstances).
But this all hinges on whether the engines were trying to run, or commanded off. Hence the request for interpretation of the sound.

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za9ra22
June 30, 2025, 22:04:00 GMT
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Post: 11913913
Originally Posted by GroundedSpanner
....The theory I'm working is...
that, given the configuration of the aircraft
What configuration, specifically?
if there is a significant electrical failure (sufficient for the RAT to auto-deploy)
Caused by what?
The aircraft fuel pumps are lost
Didn't I read somewhere in the wiki, that the engines will continue to suck fuel?
the fuel being received by the engines is arriving from a different source
Which is?
a potentially contaminated source
Contaminated with what, and how? And why were no other aircraft affected?
I believe that the engine failure is a secondary result of the power loss (with specific circumstances)
Which specific circumstances?

It isn't that your suppositions are necessarily bad ones, but that they seem a bit of a stretch. Of course I'm no expert, hence asking.

Last edited by za9ra22; 30th June 2025 at 22:19 .

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GroundedSpanner
June 30, 2025, 22:21:00 GMT
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Post: 11913922
Originally Posted by za9ra22
What configuration, specifically?

Caused by what? /
Didn't I read somewhere in the wiki, that the engines will continue to suck fuel? / Which is?
Contaminated with what, and how? And why were no other aircraft affected?
Which specific circumstances?
Here's an answer I typed earlier, that covers most of the questions. Was written before today though.

Originally Posted by GroundedSpanner
OK - Fair Challenges - good post, I'll have a go at answering and simultaneously expanding my own thoughts. In fact I'm not having a go at you, I'm more working my theory....

Experience. Without wishing to dox myself, I've worked in engineering at a major airline from apprentice through (in no particular order) Line Maintenance, Heavy and Light Maintenance, to technical support and maintenance control on both Boeing and Airbus products, with various qualifications and authorisations along the way. [Hmm - Scrap this sentence?]On the day 9/11 occurred, I should have been making modifications inside a fuel tank instead of staring at the TV with mouth on the floor.
However, I would describe my experience as broad, yet shallow in respect to this incident. Some of my fleet I know every rivet. Some of my fleet I've only ever seen from a distance. I don't touch airplanes for a living any more. B787 though - is not my area of specialty. I'll dig in, but am not the expert. I am not a systems design engineer, so precise numbers and flow rates, are not what I do. But what the systems do, how they operate, what they look like, smell and taste like... yeah, I'm not a muggle. And I do have access to all the manuals and know how to use them. And - let me be clear, I am speculating. I was advancing a theory. It WILL be some flavour of wrong. The investigation will reveal all.

I Agree, Water in fuel is not a novel concept. Aircraft fuel tanks attract water - fact. How much? It varies. I've sumped tanks and got no water, I've seen drops of water beading about in the bottom of a gallon jug, I've seen gallons of water. I've been so covered in fuel I cant smell it or think straight and taken gallon after gallon not being able to tell if its fuel or water. I also agree that 57% humidity doesn't seem particularly high - its not south east Asian jungle levels - but I'm not an expert at humidity, 32Deg c at 57% humidity at 02:30 am is not going to be comfortable for me though. I looked at recent weather in DEL, and those values were at the higher end of the range.
Further, I believe the prevailing weather conditions on the ground are less important when it comes to the volume of water getting in. Fuel is cold, or gets damn cold during a 9 Hr flight. Fuel Temperature Management is an issue for our Drivers. So as the fuel is used at altitude, Air enters the tank through NACA Ducts in the outboard end of the wing. Its beneficial to maintain a slight positive pressure, amongst other things to reduce evaporation. (Added complication, there is also the Nitrogen Enrichment system due to TWA800 - but that's more about processing the air in the tank to change the properties and make it non-explosive). Then as the aircraft descends, more air enters as the air pressure increases. Its the humidity of that air in the descent that is going to determine the volume of water entering the tank and potentially the fuel. The water in the air condenses on the sides of the tank because of the cold post-flight fuel. It doesn't dissolve into the fuel, but sinks to the bottom. Ground temperature / humidity and time will likely affect how much water condenses out of that air while on the ground. There won't be a huge amount of air exchange on the ground. Likely if the AC landed at 2am, then from sunrise as the tank warmed up, there would actually be a flow out of the vents.

What Features and procedures are there to mitigate Water? I apologise if my post gave the impression that there are no mitigation processes. There are. Water is well understood in the industry.
Well for a start, Features / Design. The Aircraft has a water scavenge system. Water doesn't mix with fuel, it sinks to the bottom being about 20% denser than fuel, so at the very lowest point in the tank, the water scavenge system (Powered by the Aft Fuel Pump through a jet pump, a venturi like system) will suck up the 'fluid' at the very lowest point, where the water would collect and in Boeings words 'drip' that fluid into the path of the pump pickup inlet (but I'd describe it more as a 'squirt'). The idea being that a small amount of water injected into the fuel will be consumed by the engines harmlessly.
There is also agitation. The wing tank pumps are pretty much running constantly, from before engine startup to after engine shutdown. The pumps are quite violent to the fuel and supply more pressure then the engine could ever need. Any excess pressure is dumped right back into the tank, quite close to the pump, in a direction that would further stir up the fuel and help break up any water into suspended droplets.
This all works if there is a small amount of water in the fuel. The water scavenge pickup is right next to the pump inlet, but a bit lower. Little bits of water get managed. Looking at the pictures of the system, I'd say a couple of gallons of water would do no harm at all.
But if there was significantly more water in that tank. Guessing 10-30 + gallons, then the pump would be circulating water, or highly water rich fuel.

Then there's the suction pickup. Its in the same 'bay' as the aft fuel pump and located a little 'higher' than the pump inlet and water scavenge inlet. But also located between stringers that can separate out the settled water ( I wish I could share the pictures, but more than my job is worth ) I can imagine the suction pickup being in a pool of 'stagnant' water.

I also saw a post from Metcha about the scavenge system blocking with Algae - I don't know about that (B787 not my fleet). But possible that could aggravate things. There's also the reports of the Indian AAIB looking at the Titan Biocide incident. Its possible that might be related and could modify the theory.

Procedures - There's the (at my airline weekly I think) procedure to 'sump' the tanks. There are drain points in the tank. Valves that you can push in with a tool and fluid drains. As described earlier (and videos exist on YouTube), you drain about a gallon of fluid and examine it for water. Most often in temperate climates (my experience), there's a few 'beads' of water in the bottom of the jug, moving about like mercury. Except when there's more. Sometimes there's a clear line in the jug, half water, fuel above. And sometimes a gallon of water, that smells like fuel. You drain it until you are sure there's no water.

Could 'that much' water have condensed in the tank? Well - There's the question. I guess the basis of the theory is that on descent into DEL, the wing tanks picked up some very humid air, which settled water into the tanks through the night. Then, as the theory I posited must work, the wing pumps must have circulated and suspended that water into the fuel.
By design, the water from the CDG-DEL arrival should have been consumed in the DEL-AMD Sector. But desperately clinging to defending my theory (I appreciate this is a hole), lets assume that at DEL the pumps were running for a long time. Lets assume that the pumps allowed the water to be dispersed within the tank prior to being used through the engines. Then - in the DEL-AMD sector, the wing tanks could have picked up more water.

How much water would cause a sustained flameout? I never posited a sustained flameout. I posited a significant reduction in thrust. Listening back to the rooftop video, which at first we were all listening for evidence of RAT, there's also a rhythmic pop-pop-pop of engines struggling. I think the engines were running, albeit badly. Heavily water contaminated fuel will do that. It doesn't have to be 100% water. Just enough water to make the engine lose thrust. Your 2 gallons per second figure assumes the engine running at full flow. I'm not a figures man, I'll not challenge that, I do recall flowmeters at max thrust spin like crazy. But an engine struggling due to a high perrcentage of contamination, is that using 2 gal/sec? or just trying to? What happens if there is e.g. 20% water in the fuel?

There are also reported incidents of engine flameout / thrust reduction that have all happened at altitude. Incidents that have been recovered due to the altitude and time available. I Posited that the engines would have eventually regained full thrust once the contamination worked though. But 30 seconds of rough engine is very different at 40,000 feet than it is at 100 feet.

The theory also relies on a second part - the electrical failure. That the electrical failure causes the fuel supply to switch, a few seconds after the failure. We go, at the point of electrical failure from a pumped centre tank supply to a sucked wing tank supply. It takes time for that different fuel to reach the engine.

Ive written enough and am tired. Must stop now.

Last edited by Senior Pilot; 30th June 2025 at 23:01 . Reason: Quote from a week ago; this is not a Hamsterwheel thread, thanks!

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fdr
June 30, 2025, 23:39:00 GMT
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Post: 11913950
Originally Posted by The Brigadier
We know that the right-hand GEnx-1B was removed for overhaul and re-installed in March 2025 so it was at \x93zero time\x94 and zero cycles, meaning a performance asymmetry that the FADEC would have to manage every time maximum thrust is selected. If the old engine was still on the pre-2021 EEC build while the fresh engine carried the post-Service Bulletin software/hardware, a dual \x93commanded rollback\x94 is plausible. A latent fault on one channel with the mid-life core can prompt the other engine to match thrust to maintain symmetry, leading to dual rollback.
However, a roll back on its own to idle would not give the evidenced gear behaviour nor the RAT (I happen to concur that the RAT was deployed and probably automatically). Given the gear tilt, it is safe to assume no engine is at idle, the normal electrical systems are not functioning at all.

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Fursty Ferret
July 09, 2025, 11:00:00 GMT
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Post: 11918308
For what it's worth, if the fuel control switches were rapidly cycled as per the dual engine failure memory actions, the engines should both have restarted and recovered full thrust within a matter of seconds. This is part of the certification and Rolls Royce publish the procedure (unofficially) as a last-ditch attempt to recover an engine that's experiencing a locked-in surge condition.

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OliTom
July 09, 2025, 11:07:00 GMT
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Post: 11918314
Originally Posted by Fursty Ferret
For what it's worth, if the fuel control switches were rapidly cycled as per the dual engine failure memory actions, the engines should both have restarted and recovered full thrust within a matter of seconds. This is part of the certification and Rolls Royce publish the procedure (unofficially) as a last-ditch attempt to recover an engine that's experiencing a locked-in surge condition.
Obvious questions, Is the procedure applicable to the GEnx engines installed on the accident aircraft and I assume this only applies if you realise the control switches are what the issue is, within seconds?

Last edited by OliTom; 9th July 2025 at 11:24 .

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Propellerhead
July 09, 2025, 12:32:00 GMT
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Post: 11918361
Originally Posted by Fursty Ferret
For what it's worth, if the fuel control switches were rapidly cycled as per the dual engine failure memory actions, the engines should both have restarted and recovered full thrust within a matter of seconds. This is part of the certification and Rolls Royce publish the procedure (unofficially) as a last-ditch attempt to recover an engine that's experiencing a locked-in surge condition.
Not sure about this. I don\x92t think the loss of thrust on both engines memory items were envisaged to be done after liftoff. It\x92s way outside the ram air start envelope. The engines would spool down fairly quickly at that low airspeed. Procedures to the operator are written by Boeing, not the engine manufacturer. And there is no procedure official or otherwise to recover a single surging engine - you either run it surge and stall free at a lower thrust or shut it down.

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V1... Ooops
July 09, 2025, 16:26:00 GMT
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Post: 11918497
There has been discussion recently about a procedure that involves moving the fuel switches to CUTOFF and then back to RUN following a dual engine failure.

Attached is an image of a page from the Air India 787 Training Manual that discusses this procedure.

I am submitting this without comment or opinion.


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Magplug
July 09, 2025, 16:57:00 GMT
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Post: 11918527
Propellerhead You are correct, a low level altitude capture would back off the throttles as the FMA goes into ALT. However the FD would drop unexpectedly as would the engine noise as the throttles rolled back..... So in what world would that prompt you to call for the dual engine failure checklist rather than firewalling the throttles? This was discussed about 75 pages ago.... It makes good reading

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Propellerhead
July 09, 2025, 17:14:00 GMT
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Post: 11918533
Yeah but thought it worth discussing again IF we believe that the engine failure was caused by a pilot selecting both fuel control switches to cutoff. You\x92re right that I can\x92t imagine myself doing it but fear can make our inner chimps do strange things in response to the flight or flight response. (See the chimp paradox book).

In what world would you feather both props instead of selecting landing flaps in Nepal and cause a fatal crash? Seemed pretty inconceivable until it happened. What we all would do in the comfort of our armchairs is very different to what can happen in the heat of the moment.



Last edited by Propellerhead; 9th July 2025 at 17:37 .

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Musician
July 09, 2025, 17:20:00 GMT
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Post: 11918536
Originally Posted by Propellerhead
Yeah but thought it worth discussing again IF we believe that the engine failure was caused by a pilot selecting both fuel control switches to cutoff. You\x92re right that I can\x92t imagine myself doing it but fear can make our inner chimps do strange things in response to the flight or flight response. (See the chimp paradox book).
Or we could wait two more days because certainly that would be in the flight recorder data.

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tdracer
July 09, 2025, 18:20:00 GMT
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Post: 11918562
Originally Posted by Propellerhead
One thing that I remember from when I was a simulator TRI/TRE on a Boeing was that as an instructor you get very used to operating critical
switches rapidly without following any procedure, in order to set the sim up for a single engine landing etc. When I was then line flying next I had to guard against doing the same thing in the real aircraft.
Muscle memory is a strange and (usually) wonderous thing. It allows us as humans to perform amazing things without actually thinking about what we are doing. Professional Athletes have perfected this to a high art, but the rest of us do things using muscle memory on a regular basis. Back when I was still racing, I happened to look down at my hands on the steering wheel in fast, bumpy corner, and I was simply amazed at the large, rapid steering inputs that I was making to compensate for the bumps - with absolutely zero conscious thought. Muscle memory at its best.

However, it can also bite us. The Delta dual engine shutdown during takeoff from LA (referenced way back when in the 1st accident thread) was caused by muscle memory - the pilot reached down to set the EEC switches (located near the fuel On-Off switches) but muscle memory caused him to do something else - set both fuel switches to OFF. Fortunately, he quickly recognized his error, placing the switches back to RUN and the engines recovered in time to prevent a water landing (barely).

It is conceivable that a pilot - reaching down to the center console to adjust something unrelated - could have muscle memory cause him to turn the fuel off to both engines. While all new engines are tested for "Quick Windmill Relight" - i.e. the fuel switch is set to CUTOFF with the engine at high power - and the engine must recover and produce thrust withing a specified time (memory says 60 or 90 seconds) - it takes a finite amount of time for the engines to recover (spool down after a power cut at high power is incredibly fast - plus moving the switch to CUTOFF causes a FADEC reset, which means it won't do anything for ~ 1 second). Doing that at a couple hundred feet and the chance that an engine will recover and start producing thrust before ground impact is pretty much zero

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Subsy
July 09, 2025, 19:23:00 GMT
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Post: 11918592
Originally Posted by tdracer
Muscle memory is a strange and (usually) wonderous thing. It allows us as humans to perform amazing things without actually thinking about what we are doing. Professional Athletes have perfected this to a high art, but the rest of us do things using muscle memory on a regular basis. Back when I was still racing, I happened to look down at my hands on the steering wheel in fast, bumpy corner, and I was simply amazed at the large, rapid steering inputs that I was making to compensate for the bumps - with absolutely zero conscious thought. Muscle memory at its best.

However, it can also bite us. The Delta dual engine shutdown during takeoff from LA (referenced way back when in the 1st accident thread) was caused by muscle memory - the pilot reached down to set the EEC switches (located near the fuel On-Off switches) but muscle memory caused him to do something else - set both fuel switches to OFF. Fortunately, he quickly recognized his error, placing the switches back to RUN and the engines recovered in time to prevent a water landing (barely).

It is conceivable that a pilot - reaching down to the center console to adjust something unrelated - could have muscle memory cause him to turn the fuel off to both engines. While all new engines are tested for "Quick Windmill Relight" - i.e. the fuel switch is set to CUTOFF with the engine at high power - and the engine must recover and produce thrust withing a specified time (memory says 60 or 90 seconds) - it takes a finite amount of time for the engines to recover (spool down after a power cut at high power is incredibly fast - plus moving the switch to CUTOFF causes a FADEC reset, which means it won't do anything for ~ 1 second). Doing that at a couple hundred feet and the chance that an engine will recover and start producing thrust before ground impact is pretty much zero
It would be a lot more conceivable if the pilot had been practicing this action in a simulator recently.

It's ironic that cognitive science arguably started with 'The Cambridge Cockpit'; an attempt to make sense of, and mitigate, pilots doing this sort of thing when tired, stressed and so on. This kick started an ergonomics revolution which appears to have come full circle. Now we have cognitive science offering Bayesian accounts of neural function that might explain how innocent but unfortunate priming of 'muscle memory' when practicing for emergencies could, almost predictably, lead to this sort of complex, protection overriding, error.

As non consciously executing a complex, well practiced, but unintended, action is a fairly common experience in less critical situations, I'm surprised that there isn't already a more effective ergonomic fix than the safety switches fitted.

Last edited by Subsy; 9th July 2025 at 21:58 .

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FullWings
July 09, 2025, 21:50:00 GMT
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Post: 11918657
Originally Posted by Magplug
Propellerhead You are correct, a low level altitude capture would back off the throttles as the FMA goes into ALT. However the FD would drop unexpectedly as would the engine noise as the throttles rolled back..... So in what world would that prompt you to call for the dual engine failure checklist rather than firewalling the throttles? This was discussed about 75 pages ago.... It makes good reading
Not to mention the thrust lever positions would be correct for the amount of power. Thinking further, it would have been manual flight and if it was a low-level acquire, you should get SPD | TO/GA | ALT or SPD | LNAV | ALT and you\x92d get the autothrottle trying to keep whichever is greater of minimum manoeuvring speed or what\x92s in the IAS window (most likely V2). None of that looks or feels like engine failure - like has been said multiple times, if the engines are running at a decent power setting and you need more thrust, the dual engine failure checklist is not the place to start when you can just push the TLs forward for a better result?

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