Nepal Plane Crash
As a non-pilot I can't understand why the controls shown at post 510 are so similar. Surely the feathering levers should be located somewhere physically away from the flap lever. I do see that there are 'buttons' on one - if they work - but otherwise there are more similarities than differences.
Join Date: Apr 2013
Location: Amsterdam
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
I was wondering, if the PM (at that time) didn't realize his mistake and not select flaps 30 (all assumption at this time of course), would the aircraft have glided further, maybe reaching the perimeter of the airfield? Or would it have stalled earlier because of higher stall speed? Is there a tradeoff? Did it slow down significantly faster and reach stall speed sooner?
Considering human factors, feathering the props at flight idle seems not to have produced much in the way of flight path change, which may have contributed to it escaping notice until power was advanced without result.
Was the crew wearing headsets? Possibly that would obscure aural clues.
One pilot began to catch on, but handed control to the apparently oblivious erring party who continued to fixate on landing instead of restoring thrust.
While it may have become impossible to restore thrust in time, a controlled impact might have done better, had the crew addressed the problem.
Was the crew wearing headsets? Possibly that would obscure aural clues.
One pilot began to catch on, but handed control to the apparently oblivious erring party who continued to fixate on landing instead of restoring thrust.
While it may have become impossible to restore thrust in time, a controlled impact might have done better, had the crew addressed the problem.
Join Date: Mar 2018
Location: Kathmandu
Posts: 46
Likes: 0
Received 0 Likes
on
0 Posts
Non-pilot here.
Noted in the report in section 1.8.4 about flight recorders is that the investigators were able to go back to a previous flight (on January 12) by the accident AC, with a different crew, that also took a circling approach from the north into RW12. That was 4 days and 23 sectors previously! A cumulative flight time according to FR24 of 695 minutes, averaging 30 minutes per sector.
That's 11 & 1/2 hours of data. Totally possible since the installed FDR had a 25-hour recording time. In an aircraft built in 2007.
Compare that to the hand-wringing on here about the recent runway incursions and near-CFIT incident aircraft having their 2-hour FDRs overwritten by the time the respective flights arrived at destination.
On a similar note I trawled through all the Yeti KTM to PKR flights since the new airport opened on January 1. The accident AC successfully flew this sector 22 times, obviously with different crews, and only twice before made a circling approach to RW12 from the north. The rest were all straight in to RW30. According to FR24 those 2 tracks each had a weird significant RH zigzag about 2/3 the way along the flightpath, possibly a result of missing data points.
Of all the numerous Yeti Airlines KTM to PKR flights I found one circling approach to RW12 from the north that had all of it's flightpath in green (meaning minimal missing data?) - flown by ATR-72 tail number 9N-ALN performing YT671 on January 4. The following screencaps show the final stage of that flight, which has not been shown in this thread previously. The second image is zoomed to show a little more detail.
Source flightradar24
Source flightradar24
Noted in the report in section 1.8.4 about flight recorders is that the investigators were able to go back to a previous flight (on January 12) by the accident AC, with a different crew, that also took a circling approach from the north into RW12. That was 4 days and 23 sectors previously! A cumulative flight time according to FR24 of 695 minutes, averaging 30 minutes per sector.
That's 11 & 1/2 hours of data. Totally possible since the installed FDR had a 25-hour recording time. In an aircraft built in 2007.
Compare that to the hand-wringing on here about the recent runway incursions and near-CFIT incident aircraft having their 2-hour FDRs overwritten by the time the respective flights arrived at destination.
On a similar note I trawled through all the Yeti KTM to PKR flights since the new airport opened on January 1. The accident AC successfully flew this sector 22 times, obviously with different crews, and only twice before made a circling approach to RW12 from the north. The rest were all straight in to RW30. According to FR24 those 2 tracks each had a weird significant RH zigzag about 2/3 the way along the flightpath, possibly a result of missing data points.
Of all the numerous Yeti Airlines KTM to PKR flights I found one circling approach to RW12 from the north that had all of it's flightpath in green (meaning minimal missing data?) - flown by ATR-72 tail number 9N-ALN performing YT671 on January 4. The following screencaps show the final stage of that flight, which has not been shown in this thread previously. The second image is zoomed to show a little more detail.
Source flightradar24
Source flightradar24
On the Path Derieved from the Live Stream : https://www.google.com/maps/d/edit?m...580580486&z=15
They are a bit wider . On the FlightRadar map , The flight path passes over the Bridge , written SOS VILLAGE . Witness who has seen these odd Flights also confirm this path that the plane should have turned by then .
On the Live Stream , That bride is visible . The Crew are already aware of the loss of power but not how and are not turning much . On the seconds before the crash , they have overshoot the runway approach path . Had they recovered , that would be a Go Around case .
Any Comment on the YAW Damper that was disconnected as a result of Feathering ? 1.1.5 of the report .
Last edited by Yo_You_Not_You_you; 19th Feb 2023 at 11:08. Reason: witness report , yaw damper
Medical issue with PM?
I’m wondering was there a medical issue affecting PM? As happened in Staines crash. He was clearly not focussed on his monitoring duties, his hand went into a non-sensical automatic mode on a pair levers to his left in response to a call for flap. He didn’t respond to PF’s mention of lack of thrust. Either he “froze” psychologically due to exhaustion or he was in the process losing consciousness, and PF too busy on her manoeuvre that she didn’t realise there was a very serious event happening PM beside her.
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 1,121
Likes: 0
Received 12 Likes
on
7 Posts
Not on a properly designed turboprop (Fokker 50). Look at the difference between all the controls, grabbing the wrong was is harder. The fuel/condition controls aren't usually moved together. We would start the engines one by one, we used to shut them down one by one. And if one fails, you most definitely don't want to maintain symetrical engine conditions. If you need to change the pitch you use the engine rating panel underneath the instruments, or the TOGA buttons on the power levers (or the skid control test button while airborne with the gear down, but that might not have been a feature....). And on the ATR I would guess most of the time something similar would apply
In the end, a single hand cannot accidentally shut down both engines.
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.
Procedural slips happen, this one is a doozy though, and the fact it was not detected by the drivers is disturbing. the follow up actions of the flap selection 40 odd seconds later did not trigger any apparent awareness by the RHS PM at that time that he had moved something a little more than half a minute earlier, yet what was supposed to move was not. The lack of curiosity is depressing, and at that time, there would not be a cognitive overload condition for an experienced pilot... at least one would hope not.
The spectral FFT detected the feathering of the props as a reduction in broad band noise, the core of the engine continued operating until after impact when they wind down. there was a question raised by that, however, to have accidentally feathered both engines and not detected that for just on a minute is a pretty sad state of affairs. The PF did finally recognise the lack of thrust but that verbalised awareness statement did not trigger any action by the RHS person who had erroneously selected the condition levers to feather, and then had more than half a minute later re selected the flaps without apparent concern or awareness of his action slip. Handing over control to the same "pilot" who at this point has set up the impending disaster, ensures that Ronald McD is not going to have a high probability of having any bandwidth left in the squirrel cage to unscramble his actions. Recovery from this was possible up to the point that the aircraft departed controlled flight. The stall is consistent with the performance of the RHS pilot exhibited throughout this event. If I was a passenger on this flight, I would be making a loud complaint on arrival at the pearly gates as to the scheduling glitch that has resulted in untimely demise of 71 of 72 occupants. The full report will undoubtedly go into length on the cognitive load of the RHS pilot, the answers however will not provide solace to the families impacted by this event. It is unfortunate that lack of situational awareness can occur to such an extent and that there is a failure of intellectual curiosity about the condition that the aircraft is in at that time, perhaps this was distracting the RHS guy from his Facebook account, Stockmarket report or daydreaming, whatever it was going on at that time that had precious little related to the term "Pilot" or the term "Monitoring". The RHS pilots training history may shed some light on what was going on.
71 of 72 people died as the PM moved the wrong levers and then didn't notice his slip for the rest of everyone else's lives. The PM noticed that the flaps that had been "not selected to 30" despite movement of some lever(s) instead ended up with a follow up selection half a minute later, and even with that recognition of what a flap gauge says, no thought balloon pops into existence... "sorry sport, was thinking of soup..." That the PF did not recognise the cause of the thrust loss is not surprising, that the RHS (I can't describe the RHS as the "PM"... Person Occupying Seat, would be more appropriate IMHO).
Input-response monitoring is a fundamental concept in control of any aircraft... It is common for complacency to occur over time, but failure to detect such an impressive error is... itself extraordinary. Compounding the disaster by aerodynamic stall is not then surprising.
At any point up to immediately before the wing drop, had curiosity suddenly broken out as to the energy state of the aircraft, the deteriorating flight path, the gauge readings on the Prop RPMs, the need to select flaps 30 twice... the alert by the PF on no power, in fact anything that would reasonably place the RHS person at the scene of a future disaster, just moving the condition levers forward would have resulted in rapid restoration of thrust and another apparently boring day.
Ergonomics and HMI will get a discussion point for sure, but, in the end an individual with a passing interest in the proceedings would have been appreciated by the remaining 71 souls.
RIP
Golly.
Last edited by fdr; 20th Feb 2023 at 02:36.
Interesting. The old HS-748 cockpit had a similarity with the levers used to shut down the engines(known as HP Cock levers) being on either side of the throttles. If you Google the it, you will also notice that the flap lever is offset not only to the right side of the right HP cock but also well aft.
In the end, a single hand cannot accidentally shut down both engines.
In the end, a single hand cannot accidentally shut down both engines.
while they got the levers right at the throttle quadrant, much else was not so brilliant. The dump valve... fire warning lights from the dark side... a fire bell that the striker was exposed to all and sundry... black over black "attitude instruments"
"call that a knife?.. this is a knife... "
Join Date: Sep 2018
Location: Yorkshire
Posts: 256
Likes: 0
Received 0 Likes
on
0 Posts
The "28K hours" is the aircrafts "experience"... crew is unstated in the preliminary report issued per Annex 13
Procedural slips happen, this one is a doozy though, and the fact it was not detected by the drivers is disturbing. the follow up actions of the flap selection 40 odd seconds later did not trigger any apparent awareness by the RHS PM at that time that he had moved something a little more than half a minute earlier, yet what was supposed to move was not. The lack of curiosity is depressing, and at that time, there would not be a cognitive overload condition for an experienced pilot... at least one would hope not.
The spectral FFT I posted some time back detected the feathering of the props, there was a question raised by that, however, to have accidentally feathered both engines and not detected that for just on a minute is a pretty sad state of affairs. The PF did finally recognise the lack of thrust but that verbalised awareness statement did not trigger any action by the RHS person who had erroneously selected the condition levers to feather, and then had more than half a minute later re selected the flaps without apparent concern or awareness of his action slip. Handing over control to the same "pilot" who at this point has set up the impending disaster, ensures that Ronald McD is not going to have a high probability of having any bandwidth left in the squirrel cage to unscramble his actions. Recovery from this was possible up to the point that the aircraft departed controlled flight. The stall is consistent with the performance of the RHS pilot exhibited throughout this event. If I was a passenger on this flight, I would be making a loud complaint on arrival at the pearly gates as to the scheduling glitch that has resulted in untimely demise of 71 of 72 occupants. The full report will undoubtedly go into length on the cognitive load of the RHS pilot, the answers however will not provide solace to the families impacted by this event. It is unfortunate that lack of situational awareness can occur to such an extent and that there is a failure of intellectual curiosity about the condition that the aircraft is in at that time, perhaps this was distracting the RHS guy from his Facebook account, Stockmarket report or daydreaming, whatever it was going on at that time that had precious little related to the term "Pilot" or the term "Monitoring". The RHS pilots training history may shed some light on what was going on.
71 of 72 people died as the PM moved the wrong levers and then didn't notice his slip for the rest of everyone else's lives. The PM noticed that the flaps that had been "not selected to 30" despite movement of some lever(s) instead ended up with a follow up selection half a minute later, and even with that recognition of what a flap gauge says, no thought balloon pops into existence... "sorry sport, was thinking of soup..." That the PF did not recognise the cause of the thrust loss is not surprising, that the RHS (I can't describe the RHS as the "PM"... Person Occupying Seat, would be more appropriate IMHO).
Input-response monitoring is a fundamental concept in control of any aircraft... It is common for complacency to occur over time, but failure to detect such an impressive error is... itself extraordinary. Compounding the disaster by aerodynamic stall is not then surprising.
At any point up to immediately before the wing drop, had curiosity suddenly broken out as to the energy state of the aircraft, the deteriorating flight path, the gauge readings on the Prop RPMs, the need to select flaps 30 twice... the alert by the PF on no power, in fact anything that would reasonably place the RHS person at the scene of a future disaster, just moving the condition levers forward would have resulted in rapid restoration of thrust and another apparently boring day.
Ergonomics and HMI will get a discussion point for sure, but, in the end an individual with a passing interest in the proceedings would have been appreciated by the remaining 71 souls.
RIP
Golly.
Procedural slips happen, this one is a doozy though, and the fact it was not detected by the drivers is disturbing. the follow up actions of the flap selection 40 odd seconds later did not trigger any apparent awareness by the RHS PM at that time that he had moved something a little more than half a minute earlier, yet what was supposed to move was not. The lack of curiosity is depressing, and at that time, there would not be a cognitive overload condition for an experienced pilot... at least one would hope not.
The spectral FFT I posted some time back detected the feathering of the props, there was a question raised by that, however, to have accidentally feathered both engines and not detected that for just on a minute is a pretty sad state of affairs. The PF did finally recognise the lack of thrust but that verbalised awareness statement did not trigger any action by the RHS person who had erroneously selected the condition levers to feather, and then had more than half a minute later re selected the flaps without apparent concern or awareness of his action slip. Handing over control to the same "pilot" who at this point has set up the impending disaster, ensures that Ronald McD is not going to have a high probability of having any bandwidth left in the squirrel cage to unscramble his actions. Recovery from this was possible up to the point that the aircraft departed controlled flight. The stall is consistent with the performance of the RHS pilot exhibited throughout this event. If I was a passenger on this flight, I would be making a loud complaint on arrival at the pearly gates as to the scheduling glitch that has resulted in untimely demise of 71 of 72 occupants. The full report will undoubtedly go into length on the cognitive load of the RHS pilot, the answers however will not provide solace to the families impacted by this event. It is unfortunate that lack of situational awareness can occur to such an extent and that there is a failure of intellectual curiosity about the condition that the aircraft is in at that time, perhaps this was distracting the RHS guy from his Facebook account, Stockmarket report or daydreaming, whatever it was going on at that time that had precious little related to the term "Pilot" or the term "Monitoring". The RHS pilots training history may shed some light on what was going on.
71 of 72 people died as the PM moved the wrong levers and then didn't notice his slip for the rest of everyone else's lives. The PM noticed that the flaps that had been "not selected to 30" despite movement of some lever(s) instead ended up with a follow up selection half a minute later, and even with that recognition of what a flap gauge says, no thought balloon pops into existence... "sorry sport, was thinking of soup..." That the PF did not recognise the cause of the thrust loss is not surprising, that the RHS (I can't describe the RHS as the "PM"... Person Occupying Seat, would be more appropriate IMHO).
Input-response monitoring is a fundamental concept in control of any aircraft... It is common for complacency to occur over time, but failure to detect such an impressive error is... itself extraordinary. Compounding the disaster by aerodynamic stall is not then surprising.
At any point up to immediately before the wing drop, had curiosity suddenly broken out as to the energy state of the aircraft, the deteriorating flight path, the gauge readings on the Prop RPMs, the need to select flaps 30 twice... the alert by the PF on no power, in fact anything that would reasonably place the RHS person at the scene of a future disaster, just moving the condition levers forward would have resulted in rapid restoration of thrust and another apparently boring day.
Ergonomics and HMI will get a discussion point for sure, but, in the end an individual with a passing interest in the proceedings would have been appreciated by the remaining 71 souls.
RIP
Golly.
But let us factor in one word: "FATIGUE".
It would be very, very, very interesting to find out how fatigued that crew, especially the RHS Pilot, were that day.
A very good Pilot could be acting as if she/he was over the drink-drive alcohol limit if totally sober but fatigued.
You have a lot to say that might be very, very relevant.
But let us factor in one word: "FATIGUE".
It would be very, very, very interesting to find out how fatigued that crew, especially the RHS Pilot, were that day.
A very good Pilot could be acting as if she/he was over the drink-drive alcohol limit if totally sober but fatigued.
But let us factor in one word: "FATIGUE".
It would be very, very, very interesting to find out how fatigued that crew, especially the RHS Pilot, were that day.
A very good Pilot could be acting as if she/he was over the drink-drive alcohol limit if totally sober but fatigued.
And, that is not a really old HS748... that is a modern version of the HS748...
while they got the levers right at the throttle quadrant, much else was not so brilliant. The dump valve... fire warning lights from the dark side... a fire bell that the striker was exposed to all and sundry... black over black "attitude instruments"
"call that a knife?.. this is a knife... "
while they got the levers right at the throttle quadrant, much else was not so brilliant. The dump valve... fire warning lights from the dark side... a fire bell that the striker was exposed to all and sundry... black over black "attitude instruments"
"call that a knife?.. this is a knife... "
In this age of inexpensive automation where I can buy for under $500 a processor of equal capacity to one that 30 years ago cost $50,000, it seems like it would work well to have an annunciation of major state changes - "GEAR UP," FLAPS 30," "FEATHER 1, FEATHER 2." Feeding back through someone who has made an error is feeding back through someone who already failed to notice they made an error. This would either enhance or remove the need for either pilot to repeat back what they were told and would give both feedback as to whether the expected action was selected so there need not be increased competition for hearing other communications. This might have been enough to avoid PIA 8303 and perhaps would have avoided this as well.
I recall one of the best TED Talks ever - "On Being Wrong" a must watch I recommend to anyone wondering how errors occur. The core problem is that being wrong feels just the same as being right. Discovering one is wrong is what feels bad, but until then there may be no push to confirm the belief is correct. By adding out-of-channel feedback it avoids a contaminated channel from interfering with understanding.
From what I have read here, it's possible the PF noticed that there had been no expected trim change that should have happened from the flap change, but didn't understand that some other change had occurred, and repeated the request which then did get followed. Had "FEATHER 1, FEATHER 2" been announced instead then both pilots would have looked to see why that happened.
I recall one of the best TED Talks ever - "On Being Wrong" a must watch I recommend to anyone wondering how errors occur. The core problem is that being wrong feels just the same as being right. Discovering one is wrong is what feels bad, but until then there may be no push to confirm the belief is correct. By adding out-of-channel feedback it avoids a contaminated channel from interfering with understanding.
From what I have read here, it's possible the PF noticed that there had been no expected trim change that should have happened from the flap change, but didn't understand that some other change had occurred, and repeated the request which then did get followed. Had "FEATHER 1, FEATHER 2" been announced instead then both pilots would have looked to see why that happened.
Join Date: May 2013
Location: Casablanca
Age: 24
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Non-pilot here.
Noted in the report in section 1.8.4 about flight recorders is that the investigators were able to go back to a previous flight (on January 12) by the accident AC, with a different crew, that also took a circling approach from the north into RW12. That was 4 days and 23 sectors previously! A cumulative flight time according to FR24 of 695 minutes, averaging 30 minutes per sector.
That's 11 & 1/2 hours of data. Totally possible since the installed FDR had a 25-hour recording time. In an aircraft built in 2007.
Compare that to the hand-wringing on here about the recent runway incursions and near-CFIT incident aircraft having their 2-hour FDRs overwritten by the time the respective flights arrived at destination.
Noted in the report in section 1.8.4 about flight recorders is that the investigators were able to go back to a previous flight (on January 12) by the accident AC, with a different crew, that also took a circling approach from the north into RW12. That was 4 days and 23 sectors previously! A cumulative flight time according to FR24 of 695 minutes, averaging 30 minutes per sector.
That's 11 & 1/2 hours of data. Totally possible since the installed FDR had a 25-hour recording time. In an aircraft built in 2007.
Compare that to the hand-wringing on here about the recent runway incursions and near-CFIT incident aircraft having their 2-hour FDRs overwritten by the time the respective flights arrived at destination.
Flight data from the planes involved in the recent runway incursions and near-CFIT incidents, may have already been extracted through QAR for FDA/FDM purposes.
I think you're confusing CVR (Cockpit Voice Recorder) and FDR (Flight Data Recorder). The latter stores a lot more data than the CVR and probably has similar specs for every airplane mentionned in your post. Looking up the ATR's CVR's reference, it does only record for 2 hours.
Flight data from the planes involved in the recent runway incursions and near-CFIT incidents, may have already been extracted through QAR for FDA/FDM purposes.
Flight data from the planes involved in the recent runway incursions and near-CFIT incidents, may have already been extracted through QAR for FDA/FDM purposes.
I’m wondering was there a medical issue affecting PM? As happened in Staines crash.
Join Date: May 2013
Location: Casablanca
Age: 24
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
I'm pretty surprised it hasn't been the case. I get that getting something certified might be a complicated process, but the amount of data that can be stored on smaller components is already mind boggling.
[QUOTE=fdr;11388438]The "28K hours" is the aircrafts "experience"... crew is unstated in the preliminary report issued per Annex 13
Not sure what you mean by this.
My statement was that between them the pilots had over 28,000 logged flying hours. I wasnt refering to any information in the report.
For 2 pilots, both captains, to have made such stupid and elmentary errors and then not recognise the results of their actions and cause a perfectly servicable aircraft to crash is unforgivable.
Enough of people saying they were tired, or fatigued or stressed, flying the bloody plane was their job and between them they screwed up.
They got too complacement relying on automation
forgot to listen to, and feel what the aircraft was doing
forgot to check what the instruments were telling them
forgot to wonder what lever did I actually move before, when selecting full flaps for the second time.
Had basically become bad system managers
and had forgotten how to fly a plane. ANC.
Not sure what you mean by this.
My statement was that between them the pilots had over 28,000 logged flying hours. I wasnt refering to any information in the report.
For 2 pilots, both captains, to have made such stupid and elmentary errors and then not recognise the results of their actions and cause a perfectly servicable aircraft to crash is unforgivable.
Enough of people saying they were tired, or fatigued or stressed, flying the bloody plane was their job and between them they screwed up.
They got too complacement relying on automation
forgot to listen to, and feel what the aircraft was doing
forgot to check what the instruments were telling them
forgot to wonder what lever did I actually move before, when selecting full flaps for the second time.
Had basically become bad system managers
and had forgotten how to fly a plane. ANC.
Under EASA’s Commission Regulation (EU) 2015/2338, aircraft with a maximum takeoff weight of 59,500 pounds manufactured after Jan. 1, 2021 must feature a CVR with a recording duration of at least 25 hours and the ability to accurately determine the location of an aircraft accident. Part of the new requirements also took effect as of Jan. 1, 2019, including the replacement of recorders featuring magnetic tape with solid-state CVRs.
Join Date: Jan 2008
Location: Canada
Posts: 631
Likes: 0
Received 0 Likes
on
0 Posts
A long time ago, when I was a newbie copilot, it was drilled into me for handing powerplant/wheels/flaps controls: "(name control) Identified " (as pilot handling engine controls puts hand on that control knob) "Confirmed" (pilot monitoring says) then the pilot handling operates the control. Is it still done this way?
June 2019 in Canada, the PNF pulled the condition levers to shutdown on a cargo Basler DC-3T by mistake, and you have to pull them past a gate to do it! Splashed the plane.
June 2019 in Canada, the PNF pulled the condition levers to shutdown on a cargo Basler DC-3T by mistake, and you have to pull them past a gate to do it! Splashed the plane.