Nepal Plane Crash
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Indeed the position is quite close to each other.
... Also that apparently no one checked position of the levers even when after applying power nothing happened. Normally even peripheral vision should have been enough to ring a bell. And all this in bright daylight. ... But from the basic facts we know chances are still very high that exactly this happened.
... Also that apparently no one checked position of the levers even when after applying power nothing happened. Normally even peripheral vision should have been enough to ring a bell. And all this in bright daylight. ... But from the basic facts we know chances are still very high that exactly this happened.
10:56:32: The PF then called for “FLAPS 30” at 10:56:32, and the PM replied, “Flaps 30 and descending”. The ...(FDR) data did not record any flap surface movement at that time. Instead, the propeller rotation speed (Np) of both engines decreased simultaneously to less than 25%1 and the torque (Tq) started decreasing to 0%, which is consistent with both propellers going into the feathered condition2. ..
10:56:54, another click was heard, followed by the flaps surface movement to the 30 degrees position...
That sounds to me like someone noticed the mistake after 20 s and pulled the flap levers to 30. Clandestine correction of error with no comment on the CVR and no check / correction of the condition levers?
If an error can be made, however unlikely, humans will find a way of making it. They will even hear, see and confirm what they expect to happen. Neither pilot seemed to notice a sudden and complete loss of power. Well, why would they, it wasn't in the mental model.
Little war story: On one of my first fights in a small aircraft (just before I began my own training), at the completion of the 150nm cross-country we ended up a bit high on final.
The newly-minted (and thus very current in training) pilot in the left seat reached over to pull back the C152's throttle and reduce power. Which he did very successfully - the engine and prop stopped altogether. He had grabbed and pulled the MIXTURE knob all the way back. Despite it being 1) screaming RED in color, and 2) having a push-button lock to prevent inadvertent movement.
At which point the excess altitude became very useful - as we glided to a perfect touchdown on the runway.
Pilots at all levels of experience can do (and have done) the darndest things. Which is why, whenever I see an argument that "No pilot would ever......," I carefully fold it four ways and deposit it in the trash-basket.
Had we crashed, the investigators would no doubt have found the mixture lever at cutoff, just as the investigators here found the condition levers at feather.
There may be two condition levers - but they are intentionally set very close together (cheek by jowl), because they are usually moved as one to maintain symmetrical engine conditions.
The newly-minted (and thus very current in training) pilot in the left seat reached over to pull back the C152's throttle and reduce power. Which he did very successfully - the engine and prop stopped altogether. He had grabbed and pulled the MIXTURE knob all the way back. Despite it being 1) screaming RED in color, and 2) having a push-button lock to prevent inadvertent movement.
At which point the excess altitude became very useful - as we glided to a perfect touchdown on the runway.
Pilots at all levels of experience can do (and have done) the darndest things. Which is why, whenever I see an argument that "No pilot would ever......," I carefully fold it four ways and deposit it in the trash-basket.
Had we crashed, the investigators would no doubt have found the mixture lever at cutoff, just as the investigators here found the condition levers at feather.
There may be two condition levers - but they are intentionally set very close together (cheek by jowl), because they are usually moved as one to maintain symmetrical engine conditions.
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Just a thought of another hole in the cheese, with two Captains flying together, how much flying had the PM done recently from the RHS? Operating levers and flows on different from your “normal” side can throw all sorts of little hesitations and errors.
My poor phrasing (still partly in C152 mode 
) - substitute "deduced from the FDR data of the Np and Torque that the propellers had been feathered."
I'd imagine that the instant they saw that data, they went back to the pile of wreckage to see if the levers could be found.
) - substitute "deduced from the FDR data of the Np and Torque that the propellers had been feathered."I'd imagine that the instant they saw that data, they went back to the pile of wreckage to see if the levers could be found.
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Props Feathered , What prevented them from gliding further out ? Stick Shaker Activated , Flaps 30 ?
What would happen if the Condition Feather was suddenly put to AUTO with engine in Full Throttle as it was in the last moments , any Unsymmetric thrusts that could have created a rollover?
What would happen if the Condition Feather was suddenly put to AUTO with engine in Full Throttle as it was in the last moments , any Unsymmetric thrusts that could have created a rollover?
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Indeed and it is why Ihave a bit difficulties in accepting a simple lever mix up. In addition to what you said, the flaps is one lever, conditions are 2 , and as someone explained earlier there should be specific buttons to push of pull to go to feather. These facts combined with quite experienced pillots , which had done 3 evious flights on the same aircraft that day , almost CAVOK., no real stress or emergency , just a request for a QFU change , it does not really add up.. .I think we are missing something here.
For similar reasons some operator require pilots, before acting on flaps or gear calls, to grab the control, repeat which they want to move, wait a second or two to allow intervention by the PF in case it is the wrong item, and only then move it. That slows things down, but prevents transferring one muscle memory movement to the wrong control.
I have found that the link doesn't work, also the same one (I think) in LinkedIn posts, however here is a link that does work: https://www.flightradar24.com/blog/w...ary-Report.pdf
Pegase Driver
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@ Denti. very interesting story, we are now getting into complex human factors,. I have seen such incidents with single pilots in high stress situations , which we call :" buried memory ", where your brain is overloaded and automaticallydoes things based on actions buried in your memories, as your brain can only function in sequences , not at the same time (despite many women believe they can ).
While the example descrbed by pattern_is_full on an old Cessna is easily understandable, as the 2 levers, throttle and mixure are not only side by side but have the same push-rotate knob, and behave the same, just the color is different. Not the first time this error occurred and will not be not the last time .
But the feeling of taking 2 round shaped levers, (de) pressing 2 knobs to get into feather instead of delatching a single flap lever with its distinctive wing shape, is totally different and frankly I never heard of this before , on any type. And not picked up by the PF either? But there is always a first on everything I agree.
One point that migh be worth looking at here is fatigue and sleep deprivation as a posible contributing factor. We know they've done 3 previous legs that morning , but what they did the night before ( not necessarly work related) can be a factor Colgan and AF447 come to mind..
But the mystery continues until we get the final report in a year or two I guess.
While the example descrbed by pattern_is_full on an old Cessna is easily understandable, as the 2 levers, throttle and mixure are not only side by side but have the same push-rotate knob, and behave the same, just the color is different. Not the first time this error occurred and will not be not the last time .
But the feeling of taking 2 round shaped levers, (de) pressing 2 knobs to get into feather instead of delatching a single flap lever with its distinctive wing shape, is totally different and frankly I never heard of this before , on any type. And not picked up by the PF either? But there is always a first on everything I agree.
One point that migh be worth looking at here is fatigue and sleep deprivation as a posible contributing factor. We know they've done 3 previous legs that morning , but what they did the night before ( not necessarly work related) can be a factor Colgan and AF447 come to mind..
But the mystery continues until we get the final report in a year or two I guess.
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For low-currency pilots in a hobby environment there have been cases where quite dissimilar controls have been confused.
Cognitive decline has also been suspected in these cases, especially when older pilots were involved.
This is a case where an airbrake handle and a gear lever were mixed up, even though they are very different in this type of glider:
- Linear action backwards vs. pivot lever action forwards
- Different shape of handle
- Different actuation force and force progression
- Blue plastic vs black metal
- High on cockpit sill vs low near armrest
I would not have expected much better trained, supervised and medically checked ATPL pilots in a two-person cockpit to have such a mix-up and not recognize/correct it.
But given the facts so far it has to be viewed as possible, even likely.
Cognitive decline has also been suspected in these cases, especially when older pilots were involved.
Since I cannot post links yet:
bea.aero/en/investigation-reports/notified-events/detail/accident-to-the-rolladen-schneider-ls4-registered-f-clmf-on-25-06-2021-at-vinon-sur-verdon/
bea.aero/fileadmin/user_upload/F-CLMF_En.pdf
bea.aero/en/investigation-reports/notified-events/detail/accident-to-the-rolladen-schneider-ls4-registered-f-clmf-on-25-06-2021-at-vinon-sur-verdon/
bea.aero/fileadmin/user_upload/F-CLMF_En.pdf
- Linear action backwards vs. pivot lever action forwards
- Different shape of handle
- Different actuation force and force progression
- Blue plastic vs black metal
- High on cockpit sill vs low near armrest
I would not have expected much better trained, supervised and medically checked ATPL pilots in a two-person cockpit to have such a mix-up and not recognize/correct it.
But given the facts so far it has to be viewed as possible, even likely.
I would like to know who initiated the change of handling pilot at the last minute. I don't think that is clear from the report.
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Indeed and it is why Ihave a bit difficulties in accepting a simple lever mix up. In addition to what you said, the flaps is one lever, conditions are 2 , and as someone explained earlier there should be specific buttons to push of pull to go to feather. These facts combined with quite experienced pillots , which had done 3 evious flights on the same aircraft that day , almost CAVOK., no real stress or emergency , just a request for a QFU change , it does not really add up.. .I think we are missing something here.
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Or worse, a crew member selected flaps up when asked for gear up. Sometimes your brain isn't engaged. How about putting the mobile phone in the fridge? Also happened to sane people.
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Crikey!
that report is simply shocking. But the signs were there right from the off.
I called the lack of prop / engine noise immediately as well as the feather scenario. But what i never expected in a million years was that it wasn’t due to a mechanical fault, but human error.
blimey its worrying.
777 pilots not checking ALT gauges before enabling AP on T/O and now ATR pilots grabbing completely the wrong levers.
The excuse of muscle memory doesn’t - nor should it - wash. Especially with levers with a totally different ergonomic feel. If they were all the same - i could somewhat understand it - but they are not, for this reason.
the fact that the error occurred and PM didn’t think “Well I didn’t get flaps 30 so what did i do” and subsequently does adjust to Flaps 30 later, still not noticing the error - is scary.
it literally feels like a lottery with the quality of the crews you get these days - almost at the point where I’m tempted to ask the flight crew some Aircraft type trivia questions before boarding.
that isn’t meant to offend those of you that are fully competent (I know despite encouraged automation, SOPS and company CRM some of you do still exist)
airframe reliability has come a long way in the last 20 years. However, Air crew reliability has gone south in a big way.
What a turnaround of events, from highly experienced and well trained crews who sadly found the hardware letting them down in times of old.
A crude estimation, but of the last 10 major Airliner accidents I can think of, at least 80% of them have been flyable aircraft.
that report is simply shocking. But the signs were there right from the off.
I called the lack of prop / engine noise immediately as well as the feather scenario. But what i never expected in a million years was that it wasn’t due to a mechanical fault, but human error.
blimey its worrying.
777 pilots not checking ALT gauges before enabling AP on T/O and now ATR pilots grabbing completely the wrong levers.
The excuse of muscle memory doesn’t - nor should it - wash. Especially with levers with a totally different ergonomic feel. If they were all the same - i could somewhat understand it - but they are not, for this reason.
the fact that the error occurred and PM didn’t think “Well I didn’t get flaps 30 so what did i do” and subsequently does adjust to Flaps 30 later, still not noticing the error - is scary.
it literally feels like a lottery with the quality of the crews you get these days - almost at the point where I’m tempted to ask the flight crew some Aircraft type trivia questions before boarding.
that isn’t meant to offend those of you that are fully competent (I know despite encouraged automation, SOPS and company CRM some of you do still exist)
airframe reliability has come a long way in the last 20 years. However, Air crew reliability has gone south in a big way.
What a turnaround of events, from highly experienced and well trained crews who sadly found the hardware letting them down in times of old.
A crude estimation, but of the last 10 major Airliner accidents I can think of, at least 80% of them have been flyable aircraft.
Last edited by RiSq; 18th Feb 2023 at 06:56.
Drain Bamaged
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There have been many, many cases of the wrong controls being moved. I know (second hand) of a few, including: hand moving to the flap lever when "gear up" called after take-off (but stopped short by an observant PF); fuel lever moved to shut-off when landing flap called for (which resulted in a single engined landing, without that final flap selection!). In both those situations the PM was the captain.
Add to that the situation of the trainer ('instructor') being in the different seat from 'normal' where everything is 'the other side'. Add to that fatigue. That was the fourth sector that day, how many had already been flown in the preceding few days and at what sort of start times or length of day? Don't be too critical of mistakes that people may make in situations like that unless you fully understand the circumstances that they were in. Or the circumstances that their work requirements had put them in. I have only known one airline that restricted the total amount of a trainer's workload that can be training. The extra workload on its own is fatiguing and being worked up to 'normal' fatigue expectations pushes this too far. There may be other airlines that also recognise that -- I hope so.
I cant understand why when the props were feathered that neither PF or PM noticed the difference in engine noise or feel or vibration of the aircraft or change in pitch angle etc.
And when the PF said repeatedly the engines are not producing power, didnt the PM do a visual scan of the controls and see that the props were feathered.
The clue is in the name, Pilot Monitoring. !!!!
Another example of a perfectly servicable aircaft being crashed into the ground by multi thousand hour (28000+) incompetent pilots.
And when the PF said repeatedly the engines are not producing power, didnt the PM do a visual scan of the controls and see that the props were feathered.
The clue is in the name, Pilot Monitoring. !!!!
Another example of a perfectly servicable aircaft being crashed into the ground by multi thousand hour (28000+) incompetent pilots.
Last edited by michaelbinary; 18th Feb 2023 at 10:04.
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Or --
-- ??
Details of all their preceding duties would be very interesting.
Another example of a perfectly servicable aircaft being crashed into the ground by multi thousand hour (28000+) incompetent exhausted/fatigued pilots.
Details of all their preceding duties would be very interesting.
