PIA A320 Crash Karachi
Only half a speed-brake
PJ2: The message was there, in the rest of your post. In agreement
a) The traditional 1000 IMC / 500 VMC wording occludes things. The target becomes moveable, which makes it harder for a pilot to understand which side of the line he's standing on, in the heat of the moment.
b) There is no practical training, hands-on instruction, on how to throw out a botched approach. Comparison to G/As from DA due to no vis reference springs to mind, the latter effectively wiped out people busting minima. Talking about the decision making here, not the execution.
c) for most of the wrongly stabilized approaches, the situation is actually getting better, converging. Siren's call.
It takes a few approaches that should have been discontinued yet were not for the human element to build sufficient resolve to act properly and on time. Ideally covered during in the F/O phase of one's career. What type of training can be scheduled to overcome this weakness?
The puzzling bit is landing from unstable is not press-home-itis, but rather a denial of having messed up (salvage-itis) and shying away from the unknown. You can only be ahead of the aircraft at one place, and if that place becomes the runway instead of the MISAP HP, it will actually feel safer just to keep aiming for the ground, no matter how improper such mindset is. The more we get involved in working the approach, the deeper trap is dug.
disclaimer: All irrelevant to the PIA tragedy discussed, which is too bizarre to understand given what's known.
a) The traditional 1000 IMC / 500 VMC wording occludes things. The target becomes moveable, which makes it harder for a pilot to understand which side of the line he's standing on, in the heat of the moment.
b) There is no practical training, hands-on instruction, on how to throw out a botched approach. Comparison to G/As from DA due to no vis reference springs to mind, the latter effectively wiped out people busting minima. Talking about the decision making here, not the execution.
c) for most of the wrongly stabilized approaches, the situation is actually getting better, converging. Siren's call.
It takes a few approaches that should have been discontinued yet were not for the human element to build sufficient resolve to act properly and on time. Ideally covered during in the F/O phase of one's career. What type of training can be scheduled to overcome this weakness?
The puzzling bit is landing from unstable is not press-home-itis, but rather a denial of having messed up (salvage-itis) and shying away from the unknown. You can only be ahead of the aircraft at one place, and if that place becomes the runway instead of the MISAP HP, it will actually feel safer just to keep aiming for the ground, no matter how improper such mindset is. The more we get involved in working the approach, the deeper trap is dug.
disclaimer: All irrelevant to the PIA tragedy discussed, which is too bizarre to understand given what's known.
Interesting. I hadn't really thought of the "what if they had just plunked it hard down first time round" question. One to think about; though far beyond my paygrade, such as it is. And, as far beyond my paygrade but in a different direction, a couple of long-time forum members, engineering types, early in the thread drew attention to the lower tubing layout in these particular engines rendering them especially "sensitive" to this horribly hard scrape. ....
Airbuba is correct too, hence why I said "may have had a far higher survival rate had it played out to a stop on the ground" - either way, it was going to be a mess, particularly given the apparent speeds involved over the threshold for Event 1. I'd have put survival of an initial pancake at "slim" - I'm just amazed anyone made it out of the second event at all. The Pan Am story shows that, once you've taken a plane outside it's design envelope, you are a bit in the lap of the gods. For Pan Am it worked - for these guys it didn't.
However, PJ2 (and FlightDetent with "The more we get involved in working the approach, the deeper trap is dug.") have a very salient point which I personally think is behind lots of accidents - and one I have come across ever since I was a "lowly" PPL. "FOQA/FDM data typically shows a very low non-stable approach to go-around ratio. Despite the data being presented to pilots and management/training alike, breaking through this phenomena has proven difficult." The number of times I have "done the right thing" and thrown an approach away, or held 2 or 3 minutes until the Wx has cleared through before landing - and then been taken to task is absolutely shocking - good CFIs/Instructors/ATCOs even - who have "had a go" when I have "done the right thing" is a real worry and, if my experience is anything to go by, no wonder people instinctively "press on"! Thankfully, I'm an argumentative so-and-so - and my career has never been on the line due to an "event" - so I've ignored the rebuke/insult to my professional approach and done the same the next time.
I think there were more HF elements involved here (see my dit about orbiting B737s on final) but, like the iceberg, we just never hear of those things which go wrong but people escape from - even in this "big brother" world of airlines routinely analysing post-flight data. Much useful info is buried deep below the waterline or just ignored.
Anyway, I'll shut up now - I can be sooooo very boring ....!!!
No probs AGBagb, and really sorry if I came across a bit "iffy" - but worth thinking about what designers expect, anticipate what their kit may face and what is, seemingly in this case, one hell of an outlier. And yes, my background is both as an Aerospace Engineer and Commercial Pilot (typical case of "jack of 2 trades - rubbish at both???!!!") hence my take on what is expected/mitigated against in Engineering terms. There will probably be good aero/design reasons to keep some stuff low in the engines - even if just to ensure a good airflow between the top of the engines and the underneath of the wings - don't know as never worked in that field - but I could see that having an effect on say, cruise performance = cost per seat mile! Also, if they'd initiated the go-around before the ground contact, they may not even have realised the ground contact. Timing and the subsequent human filtering and/or delay in processing the sensory input then making a subsequent decision all goes into the mix - that's if they had realised - but sounds like the Capt was past making rational decisions - again, the CVR transcript could help there, as several have pointed out, in how we gain an understanding of the thought processes leading up to Event 1 and the go-around.
Interesting. I hadn't really thought of the "what if they had just plunked it hard down first time round" question.
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During certification belly landing is assessed for crasworthiness. It includes various configuration of retracted/extended landing gears (nose etc.). Purpose is to minimise the risk of fire by controlling to the maximum extent the amount of flammable fluid that could be released, by ensuring both structural integrity and/or proper location of components carrying or containing flammable fluids.
The normal assumption is however the crew will not try to take off after a belly landing. This was generally verified in service - until now. Most procedures recommended pulling the fire handles just before the landing/impact; there has been some debate because it may affect hydraulic generation and cause flight control issues.
So, no demonstration the propulsion system will run after a belly landing, and no performance calculation!
The normal assumption is however the crew will not try to take off after a belly landing. This was generally verified in service - until now. Most procedures recommended pulling the fire handles just before the landing/impact; there has been some debate because it may affect hydraulic generation and cause flight control issues.
So, no demonstration the propulsion system will run after a belly landing, and no performance calculation!
Last edited by armagnac2010; 7th Jun 2020 at 23:51. Reason: Typos
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Once you make the decision to put the gearbox on the fan case (and as I noted in a post early in this thread, on a CFM sized engine there simply isn't room to mount it on the core as is done on some bigger engines such as the PW4000 and GE90), part of it has to go at the six o'clock position. The reasons is quite simple - the gearbox drive shaft comes through the lower bifurcation. Putting the gearbox drive anyplace else would require a radical redesign of the entire engine nacelle - throwing away billions of hours of operational experience with the current design practices - and would probably create far more problems than it might solve.
Once you make the decision to put the gearbox on the fan case (and as I noted in a post early in this thread, on a CFM sized engine there simply isn't room to mount it on the core as is done on some bigger engines such as the PW4000 and GE90), part of it has to go at the six o'clock position. The reasons is quite simple - the gearbox drive shaft comes through the lower bifurcation. Putting the gearbox drive anyplace else would require a radical redesign of the entire engine nacelle - throwing away billions of hours of operational experience with the current design practices - and would probably create far more problems than it might solve.
Interesting. I hadn't really thought of the "what if they had just plunked it hard down first time round" question. One to think about; though far beyond my paygrade, such as it is. And, as far beyond my paygrade but in a different direction, a couple of long-tim,e forum members, engineering types, early in the thread drew attention to the lower tubing layout in these particular engines rendering them especially "sensitive" to this horribly hard scrape. If that's the case - not my paygrade, excuse my ignorance.... - good folks will be looking at the issue.
It's one of the things I love about the aviation community - there's always someone who will be saying, Hmmm - is there anything I could do to stop those cheese-holes lining up quite like this next time?
It's one of the things I love about the aviation community - there's always someone who will be saying, Hmmm - is there anything I could do to stop those cheese-holes lining up quite like this next time?
https://www.atsb.gov.au/media/577788...-080_final.pdf
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Is there any insight on what ECAM warnings they got after ripping of their engine ancilleries and how long it took them to realize that the donks are toast and on their last breath?
I believe the glide ratio of an A320 was around 1:20. They gained about 3000ft.
Would the height gained be sufficient to complete a teardrop or even a full circuit if aircraft was configured correctly?
Which would have been - gear up, flaps 1? Would they have been able to configure the plane after loosing two hydraulic systems?
What about the wisdom to try to fly a circuit on that instead of teardrop maneuver or just putting it in an open space? Ditching could have been an option as well, sea is about 7nm on extended crosswind.
I believe the glide ratio of an A320 was around 1:20. They gained about 3000ft.
Would the height gained be sufficient to complete a teardrop or even a full circuit if aircraft was configured correctly?
Which would have been - gear up, flaps 1? Would they have been able to configure the plane after loosing two hydraulic systems?
What about the wisdom to try to fly a circuit on that instead of teardrop maneuver or just putting it in an open space? Ditching could have been an option as well, sea is about 7nm on extended crosswind.
Last edited by BDAttitude; 8th Jun 2020 at 05:53.
To expect after the former „performance“ all of a sudden sharp airmanship, is a lot to ask for.
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Agree. It does not make too much sense to speculate in a "Sully style scenario" (and in fact it did not make much sense back then either) when we are, in that case, talking about a clear VMC day with what strongly seems to appear a perfectly efficient aircraft.
Once you make the decision to put the gearbox on the fan case (and as I noted in a post early in this thread, on a CFM sized engine there simply isn't room to mount it on the core as is done on some bigger engines such as the PW4000 and GE90), part of it has to go at the six o'clock position. The reasons is quite simple - the gearbox drive shaft comes through the lower bifurcation. Putting the gearbox drive anyplace else would require a radical redesign of the entire engine nacelle - throwing away billions of hours of operational experience with the current design practices - and would probably create far more problems than it might solve.
That necessitates deciding to retain a drive out the bottom of the engine which, as you say, now has many hours of safe useage/history behind it. Clearly, when the new higher by-pass CFM56's engines came along, initially they were aimed at the DC8/707/KC-135 and so ground clearance was not an issue - but accessibility for maintenance on the line must have been. When ported to the 737, the increased fan diameter on the -56, IIR, led to some head-scratching and several things were pushed out to either side (and fan downsized against the earlier -56's) when fitted to the 737's (here we go with re-using an old design airframe - done to death in the Max threads!), hence the semi-elliptical/"squidged" shape of the CFM56 on the 737.
Interestingly, with better ground clearance, everything is retained (I assume - I stand to be corrected) closer to the 6 o'clock position on the A319/320. The Pan Am "incident" noted by Airbuba must have been a 737-200 so that's JT8D's which also had the accessories at 6 o'clock so they were very fortunate to make it round in their roulette game. Regarding the larger engines, as lomapaseo notes, even if you protect the ancillaries moving them towards the core, distortion of the fan casing due to ground contact will then be an issue. Thinking about it, there have (as illustrated by megan) been cases of turboprops and pistons brushing props on the runway during landing/go-around incidents/accidents - but it all goes back to Statistics in the end - rare in the jets.
All in all, it points to the simple fact that landing on your engines (for whatever reason) is definitely something that comes under the "that's a rather bad idea" category - and then re-aviating after such an event is even worse!!!!! Megan has it summed up perfectly - "You can't completely design out human failures, or stupid."! Mmmmm, you ever flown with me megan? - I relate well to your quip - particularly the latter bit of it!
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No probs AGBagb, and really sorry if I came across a bit "iffy" - but worth thinking about what designers expect, anticipate what their kit may face and what is, seemingly in this case, one hell of an outlier. And yes, my background is both as an Aerospace Engineer and Commercial Pilot (typical case of "jack of 2 trades - rubbish at both???!!!") hence my take on what is expected/mitigated against in Engineering terms. There will probably be good aero/design reasons to keep some stuff low in the engines - even if just to ensure a good airflow between the top of the engines and the underneath of the wings - don't know as never worked in that field - but I could see that having an effect on say, cruise performance = cost per seat mile!
Putting an LRU low on the engine reduces down-time quite a bit: Filling up the oil also shouldn't require a scissorlift.
It's the little things that add up, after all...
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I've read most of the posts on this incident and feel the most important thing is not to enter into the realms of 'suppose' and 'what if' which are easy to do when sitting in front of your PC. We must think what can we do to prevent this happening again? Hopefully there will be an intermediate report and safety guidance issued to operators which I strongly suspect will involve the implications of inadequate human factors training. It may well be that this accident will be used to illustrate the consequences of shortcomings in this training. Basic stick and rudder flying is relatively easy, BUT to operate a modern automated aircraft requires many skills and a conducive working environment.
Only half a speed-brake
Originally Posted by MaximumPete
which I strongly suspect will involve the implications of inadequate human factors training. It may well be that this accident will be used to illustrate the consequences of shortcomings in this training. ...[deleted]
to operate a modern automated aircraft requires many skills and a conducive working environment.
to operate a modern automated aircraft requires many skills and a conducive working environment.
Imagine a doctor prepared for a surgery with his team, to remove a non-malignant tumour from the abdomen. The tools ready in hand, line drawn across the underbelly - and then cutting both ears off the skull and sawing them on the patient's back in a butterfly wing shape. What kind of missing training or remedial course would we propose to prevent re-occurence?
UNLESS the whole 1st approach was deliberate, except forgetting to drop the Dunlops in the heat of whatever game they were playing.
de minimus non curat lex
The first Q raised was the drag effect caused by deploying the gear. Gliding range.
The second Q was turning ( pointing ) towards the runway following loss of thrust, as in FLY the aircraft.
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I find it inconceivable that anyone would attempt to "go" once the "touch" resulted in a loud scraping noise. There was no possible way to know what else would be going wrong after the scraping noise, followed by the "go."
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Whether or not you can hear that scraping from the cockpit..... we got to ask the professionals
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