Turkish airliner crashes at Schiphol
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There is simply no comparison between the BA accident and the Turkish one. The BA crew lost thrust and then both engines in the space of about 300 ft at low level. The THY crew (all three of them) managed to ignore thrust levers at idle from 2000 ft to about 400 ft. Throughout the whole shameful episode there were two perfectly good engines available to any half-awake pilot to arrest the speed decay. This requires that at least one of the three was actually monitoring the progress (or lack of it) of the airspeed and the descent on the ILS. To give the aircraft its due the autopilot did what it should do and held the G/S until the speed was 35 kts below Vref.
While the initial problem of the No1 Rad Alt was the basic problem, the crew simply failed to do their job until they were woken up by the stick-shaker by which time it was almost certainly too late to correct it in the height that was left.
Perfectly flyable aircraft but let down by a very poor crew. In the BA case unserviceable aircraft (reason not determined) saved by a top-class crew.
I know which airline I won't fly with!
While the initial problem of the No1 Rad Alt was the basic problem, the crew simply failed to do their job until they were woken up by the stick-shaker by which time it was almost certainly too late to correct it in the height that was left.
Perfectly flyable aircraft but let down by a very poor crew. In the BA case unserviceable aircraft (reason not determined) saved by a top-class crew.
I know which airline I won't fly with!
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I trust we are soon expecting a full report on the Turkish arrival at Amsterdam, including cockpit voice recording.
Anything less than complete disclosure would be unfair to the pilots as we don't know what could have distracted them at such a critical time.
Anything less than complete disclosure would be unfair to the pilots as we don't know what could have distracted them at such a critical time.
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What the BA crew did that made a difference
A look at the interim reports on the BA 777 event will show that the pilots did a number of things that made the difference between reaching relatively unobstructed ground and landing on the A30. In the latter case the outcome would undoubtedly have been far worse.
SFLY,
I'm both a Glider and a 777 Pilot and in this case, your Aerodynamics are simply wrong.
Best glide speed will give longest glide STEADY STATE. You CAN, however, extend glide beyond that by using energy by INCREASING AOA and flying at a reducing airspeed over a short priod. If the end of that period ic coincident with landing, you have optimised your performance.
Your contention is that the BA38 crew wolud have been better off maintaining a higher speed. simply-not-true.
If the aeroplane had been flown at best glide speed, it would have crashed short of the airport. Following the glideslope was the best idea available at the time, as it led to the runway! When that was no longer possible, dropping below G/S and landing short, but on the airfield led to what was, in the end, the optimum result available.
Let's make it clear- if they had done what you suggest most on board and probably may more on the ground would now be dead.
As to the Turkish crash, they had a servicable aircraft with two running engines that had a minor glitch. If we have seeded responsibility for monitoring airspeed to the automatics, we are entering a very dangerous phase in aviation history.
You are being given good gen by several competent people here, and largely ignoring it.
If you are a professional aviator, "I'm right and everyone else is wrong" is a dangerous attitude to hold.
I'm both a Glider and a 777 Pilot and in this case, your Aerodynamics are simply wrong.
Best glide speed will give longest glide STEADY STATE. You CAN, however, extend glide beyond that by using energy by INCREASING AOA and flying at a reducing airspeed over a short priod. If the end of that period ic coincident with landing, you have optimised your performance.
Your contention is that the BA38 crew wolud have been better off maintaining a higher speed. simply-not-true.
If the aeroplane had been flown at best glide speed, it would have crashed short of the airport. Following the glideslope was the best idea available at the time, as it led to the runway! When that was no longer possible, dropping below G/S and landing short, but on the airfield led to what was, in the end, the optimum result available.
Let's make it clear- if they had done what you suggest most on board and probably may more on the ground would now be dead.
As to the Turkish crash, they had a servicable aircraft with two running engines that had a minor glitch. If we have seeded responsibility for monitoring airspeed to the automatics, we are entering a very dangerous phase in aviation history.
You are being given good gen by several competent people here, and largely ignoring it.
If you are a professional aviator, "I'm right and everyone else is wrong" is a dangerous attitude to hold.
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wizfoz , gliding a 777
Wizfoz
You describe a landing flare in an interesting way.
Starting your landing flare at several hundred feet must have given you interesting moments.
Please describe
You describe a landing flare in an interesting way.
Starting your landing flare at several hundred feet must have given you interesting moments.
Please describe
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He's telling us something about a power-off emergency landing, when you use up the stored energy (speed and altitude) of a large aircraft to get as far along as you can. That is not the way you do a normal landing nor did he describe it as such. For a normal landing you depend on thrust from the engines to maintain the glidepath. It would be possible to start an approach from a point where you set the engines to idle but then flight-path control would depend on nothing changing (updrafts, downdrafts, headwinds, tailwinds) so that just isn't the way it's done in the real world.
I think some of you are missing the point that what was so special about what the BA crew accomplished was that it was done in a way that we don't normally train for. A double engine failure on short final is a statistical near-impossibility in a large aircraft so that valuable training time is not spent covering that. (I have had it but just in those last few minutes after we had done all the mandatory stuff, just "having a jolly," so to speak.)
The first problem, as you might imagine, is "delayed recognition" when pushing the power levers forward yields... nothing! From this point one has to "think outside the box" when most airline flying seems to involve the opposite.
This "delayed recognition" may well feature in the report about the Schiphol crash as well but that is about the only point of similarity I can see.
I think some of you are missing the point that what was so special about what the BA crew accomplished was that it was done in a way that we don't normally train for. A double engine failure on short final is a statistical near-impossibility in a large aircraft so that valuable training time is not spent covering that. (I have had it but just in those last few minutes after we had done all the mandatory stuff, just "having a jolly," so to speak.)
The first problem, as you might imagine, is "delayed recognition" when pushing the power levers forward yields... nothing! From this point one has to "think outside the box" when most airline flying seems to involve the opposite.
This "delayed recognition" may well feature in the report about the Schiphol crash as well but that is about the only point of similarity I can see.
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The most charitable thing that I can think about S.F.L.Y. is that he's actually a lawyer for the victims in the Turkish crash, trolling for ammunition for the lawsuit. If he's really a pilot, I don't look forward to having him/her in my cockpit.
wilyflier (AMAZING how appropriate some peoples handles are!!)
chuks has quite accuratley set you straight on what I (and everyone else except SFLY) have been saying about BA38. They had idle thrust and the need to get as close to the runway as possible. They achieved that. The Turkish gus had two normall running engines and did not.
chuks has quite accuratley set you straight on what I (and everyone else except SFLY) have been saying about BA38. They had idle thrust and the need to get as close to the runway as possible. They achieved that. The Turkish gus had two normall running engines and did not.
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Wiz, you initially tell us that to fly a glider as far as possible you first need to fly at best glide speed then to use the extra energy by increasing the AOA in order to stretch the glide in a way that (optimally) the minimum speed (stall) coincides with the landing.
In BA's case they never maintained a reasonable gliding speed in order to optimize perfs before a flare but kept it constantly decreasing until they almost stall. Secondly, instead of flying an optimized path, they kept flying the GS which leads a thousand feet beyond threshold, at cost of precious speed and for no benefit at all.
It's nice to remind that the Turkish crew had fully serviceable engines which probably contributed to its fate. What would have been the 777's trajectory should it have recovered full thrust just after stick shaker activation and in IMC?
Since you still didn't get it, let me say it again: I don't care to know who was right or wrong, I have no idea if I would have done better than the BA or even the Turkish guys. That's basically not the point and I'm much more interested in the mechanisms that leads to some actions that to judging these actions.
A lot of people agrees on the fact that the BA guys' professionalism shouldn't be discussed while they are very prompt to judge the Turkish pilots. I find it little bit unfair, especially when in my opinion the BA guys didn't perform any miracle by wasting energy on the glide slope. They basically started to act on the controls when no energy was left.
Someone made an excellent comment on the fact that both crews couldn't act in an appropriate manner without recognizing and accepting their respective situations. Understanding what contributes to delay the acceptance of the situation is probably the most important issue in both accidents.
Who knows if at some point these Turkish guys thought they were experiencing a similar situation as in the BA's case?
In BA's case they never maintained a reasonable gliding speed in order to optimize perfs before a flare but kept it constantly decreasing until they almost stall. Secondly, instead of flying an optimized path, they kept flying the GS which leads a thousand feet beyond threshold, at cost of precious speed and for no benefit at all.
It's nice to remind that the Turkish crew had fully serviceable engines which probably contributed to its fate. What would have been the 777's trajectory should it have recovered full thrust just after stick shaker activation and in IMC?
Since you still didn't get it, let me say it again: I don't care to know who was right or wrong, I have no idea if I would have done better than the BA or even the Turkish guys. That's basically not the point and I'm much more interested in the mechanisms that leads to some actions that to judging these actions.
A lot of people agrees on the fact that the BA guys' professionalism shouldn't be discussed while they are very prompt to judge the Turkish pilots. I find it little bit unfair, especially when in my opinion the BA guys didn't perform any miracle by wasting energy on the glide slope. They basically started to act on the controls when no energy was left.
Someone made an excellent comment on the fact that both crews couldn't act in an appropriate manner without recognizing and accepting their respective situations. Understanding what contributes to delay the acceptance of the situation is probably the most important issue in both accidents.
Who knows if at some point these Turkish guys thought they were experiencing a similar situation as in the BA's case?
SFLY,
That is actually not an entirely unreasnoble post, but I still have differences from you.
I still dispute that there was anything the BA crew could have done that might have led to a better result. I have in fact been led to believe that, had they taken flap20 instead of Flap 25, they may have made the runway. This would have actually been worse as the impact would have been on tarmac instead of grass.
There was certainly no deviation from what they were trained to do, as they had never been trained to handle this situation. Is it possible that a more optimum flightpath was possible? Almost certainly. Is it reasnoble to expect them to achieve it under the cirumstances? Certainly not.
The Turkish case was different. It is basic CRM that one pilot is always exclusivley charged with monitoring the flight parameters of the aircraft, and in critical stages of flight the OTHER sholid be monitoring HIM. If an Automatic system does not do as expected, and imediate downgrade or dis-connect should be made. This was a case when it is clear the crew did not perform their most basic task- flying the aeroplane- to a satisfactory level.
You talk about mechanisms. If we are in an era where allowing airspeed to reduce to stall because of total relience on an automated system is excusable, then we indeed have a systemic problem.
Are you really saying they might have mistaken idle thrust with the T/Ls AT idle for a double engine failure?
For either the 737 or the 777, that should have resulted in a climb and a safe go-around. Approach to satll is something we DO train for.
That is actually not an entirely unreasnoble post, but I still have differences from you.
I still dispute that there was anything the BA crew could have done that might have led to a better result. I have in fact been led to believe that, had they taken flap20 instead of Flap 25, they may have made the runway. This would have actually been worse as the impact would have been on tarmac instead of grass.
There was certainly no deviation from what they were trained to do, as they had never been trained to handle this situation. Is it possible that a more optimum flightpath was possible? Almost certainly. Is it reasnoble to expect them to achieve it under the cirumstances? Certainly not.
The Turkish case was different. It is basic CRM that one pilot is always exclusivley charged with monitoring the flight parameters of the aircraft, and in critical stages of flight the OTHER sholid be monitoring HIM. If an Automatic system does not do as expected, and imediate downgrade or dis-connect should be made. This was a case when it is clear the crew did not perform their most basic task- flying the aeroplane- to a satisfactory level.
You talk about mechanisms. If we are in an era where allowing airspeed to reduce to stall because of total relience on an automated system is excusable, then we indeed have a systemic problem.
Who knows if at some point these Turkish guys thought they were experiencing a similar situation as in the BA's case?
It's nice to remind that the Turkish crew had fully serviceable engines which probably contributed to its fate. What would have been the 777's trajectory should it have recovered full thrust just after stick shaker activation and in IMC?
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What total b@llocks this thread has descended into. By all means compare the Turkish "accident" with the Thomson "incident" @ BOH. The only differences there were the mechanism by which the A/T did not function as expected, the lack of worsening of the situation by the A/T mishandling after the stall,& the height avail for recovery.
Again, how thick do you have to be , to see clearly, that the BA crew were trying to resolve a major malfunction, whilst maintaining a reasonable approach path. The Turkish crew created their own situation by totally failing to monitor the basic parameters of an effectively servicable aircraft.
The BA Capt used all the resources (the F/O ) whilst he tried to resolve the situation, and yes , the F/O used the AP to fly the LOC/GS. Arguably it may theoretically have been better to abandon the glidepath and fly faster until a bit later in the approach , before adopting energy re-utilisation, but that goes against all the training and habits we develop and are tested on, which is to maintain the glide path. Furthermore they had , in all likelihood, never received training in this situation, are you trying to tell me the Turkish crew were never trained to monitor airspeed during an approach ? DUH ! !
I cannot think of 100 ways to phrase this, what do you find so difficult to understand.
1 crew were faced with an untrained for emergency, very late on the approach, and indeed , bearing in mind the previous comments about the energy avail between best L/D and stall, to MAYBE make the Runway at any cost ,perhaps sacrificing a smooth touchdown, in preference to a touchdown in the airport environs at least, was perhaps the only thing they were concentrating on, and perhaps the only thing realistically they could do.
This they did, what were the Turkish crew concentrating on during their approach, with both engines responding normally if only asked ?
Counting the tulips in the fields ? or what ?
To recap, 1 crew found themselves in a high AoA situation close to the ground courtesy of the worst malfunction possible at that stage of flight, and did what they felt best, to utilise the energy they had to make the airport, at least, it worked.
Crew 2 (for reasons that we don't know, and may even be understandable up to a point, although somehow I think this will be stretching the point) put themselves in a similar situation a bit higher off the ground. . . I repeat PUT THEMSELVES IN A SIMILAR SITUATION.
Do you see the difference yet ?
To answer your totally outrageous and impertinent question, why are one crew heroes and the other being portrayed as zeroes ?
1 crew did the best any of us could have probably achieved, following a totally unrehearsed major emergency at low altitude.
The other crew somehow contrived to CREATE a similar situation all on their own, which they sadly failed to recover from, and paid the ultimate price for, as is sometimes the case in this profession we choose.
DO YOU FINALLY GET IT ?
Again, how thick do you have to be , to see clearly, that the BA crew were trying to resolve a major malfunction, whilst maintaining a reasonable approach path. The Turkish crew created their own situation by totally failing to monitor the basic parameters of an effectively servicable aircraft.
The BA Capt used all the resources (the F/O ) whilst he tried to resolve the situation, and yes , the F/O used the AP to fly the LOC/GS. Arguably it may theoretically have been better to abandon the glidepath and fly faster until a bit later in the approach , before adopting energy re-utilisation, but that goes against all the training and habits we develop and are tested on, which is to maintain the glide path. Furthermore they had , in all likelihood, never received training in this situation, are you trying to tell me the Turkish crew were never trained to monitor airspeed during an approach ? DUH ! !
I cannot think of 100 ways to phrase this, what do you find so difficult to understand.
1 crew were faced with an untrained for emergency, very late on the approach, and indeed , bearing in mind the previous comments about the energy avail between best L/D and stall, to MAYBE make the Runway at any cost ,perhaps sacrificing a smooth touchdown, in preference to a touchdown in the airport environs at least, was perhaps the only thing they were concentrating on, and perhaps the only thing realistically they could do.
This they did, what were the Turkish crew concentrating on during their approach, with both engines responding normally if only asked ?
Counting the tulips in the fields ? or what ?
To recap, 1 crew found themselves in a high AoA situation close to the ground courtesy of the worst malfunction possible at that stage of flight, and did what they felt best, to utilise the energy they had to make the airport, at least, it worked.
Crew 2 (for reasons that we don't know, and may even be understandable up to a point, although somehow I think this will be stretching the point) put themselves in a similar situation a bit higher off the ground. . . I repeat PUT THEMSELVES IN A SIMILAR SITUATION.
Do you see the difference yet ?
To answer your totally outrageous and impertinent question, why are one crew heroes and the other being portrayed as zeroes ?
1 crew did the best any of us could have probably achieved, following a totally unrehearsed major emergency at low altitude.
The other crew somehow contrived to CREATE a similar situation all on their own, which they sadly failed to recover from, and paid the ultimate price for, as is sometimes the case in this profession we choose.
DO YOU FINALLY GET IT ?
Last edited by captplaystation; 30th Jan 2010 at 18:54.
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He (S.F.L.Y) is still grinding his axe for whatever reason, maybe he is of Turkish origin, but whatever the facts that may be presented to him he will still harp on about angle of attack - and continue to IGNORE the fact that the Turkish crew had two good engines available had they elected to use them. He seems to ignore the fact that the BA crew had actually lost all thrust at a VERY late stage of an ILS approach - AND THE FACT THAT THEY ATTEMPTED (STILL WITHOUT THRUST AVAILABLE) TO IMPROVE THE GLIDE PERFORMANCE BY RETRACTING THE FLAP POSITION!!
Which bit of this argument can you continue to ignore SFLY? Are you completely deranged, or only partially attached to reality?
Which bit of this argument can you continue to ignore SFLY? Are you completely deranged, or only partially attached to reality?
Perhaps 'critical thinking' may assist those considering further contributions to this thread.
A guide for posting on Pprune? A guide to professionalism? Probably a guide for situation awareness and decision making, aspects of airmanship.
Also, see:
http://www.skybrary.aero/bookshelf/books/758.ppt
A guide for posting on Pprune? A guide to professionalism? Probably a guide for situation awareness and decision making, aspects of airmanship.
Also, see:
http://www.skybrary.aero/bookshelf/books/758.ppt
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What no one has stated is how far would the plane have flown if a higher speed, probably closer to Vref L/D, had been maintained.
Vref was 135. Flaps 25 was selected at 118 kts. That's approx. 1.1 Vso instead of the typically 1.3 Vso. I've been told by a flight test engineer that Vref L/D is usually slighter higher than 1.3 Vso. If true, 1.1 Vso would reduce your gliding performance. 1.1 Vso should be worse performance anyway. Clean L/D in my current a/c is 1.35 Vsi. I wouldn't be surprised if Vso L/D is also 1.35.
I'm with S.F.L.Y. when it comes to the performance questions.
I've read the interim report. The report stated that 'the crew retracted flaps in an attempt to reduce drag'(page 4). It does not say the crews actions were successful or adviseable. It just states what the crew believed, which isn't necessarily the correct answer.
Engine power was still present. Fuel flow was 5K and 6K, or approx. 2/3's typical fuel flow. Duplicated in sim with engines at idle...crashed. The glide performance will be better with 2/3's typical fuel flow.
What the AAIB needs to do is refly the exact same scenario and do nothing. That will be the ultimate decider if the crew's actions increased, or decreased, the aircraft's performance.
Vref was 135. Flaps 25 was selected at 118 kts. That's approx. 1.1 Vso instead of the typically 1.3 Vso. I've been told by a flight test engineer that Vref L/D is usually slighter higher than 1.3 Vso. If true, 1.1 Vso would reduce your gliding performance. 1.1 Vso should be worse performance anyway. Clean L/D in my current a/c is 1.35 Vsi. I wouldn't be surprised if Vso L/D is also 1.35.
I'm with S.F.L.Y. when it comes to the performance questions.
I've read the interim report. The report stated that 'the crew retracted flaps in an attempt to reduce drag'(page 4). It does not say the crews actions were successful or adviseable. It just states what the crew believed, which isn't necessarily the correct answer.
Engine power was still present. Fuel flow was 5K and 6K, or approx. 2/3's typical fuel flow. Duplicated in sim with engines at idle...crashed. The glide performance will be better with 2/3's typical fuel flow.
What the AAIB needs to do is refly the exact same scenario and do nothing. That will be the ultimate decider if the crew's actions increased, or decreased, the aircraft's performance.
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Refly BA038?
According to misd-again - "What the AAIB needs to do is refly the exact same scenario and do nothing. That will be the ultimate decider if the crew's actions increased, or decreased, the aircraft's performance."
How will that improve air safety? Whether the crew increased or decreased the aircraft's performance, what matters is that everyone survived without any life-threatening injuries. Seems pretty hard to improve on that result.
(And why are we discussing BA038 on this forum anyway?)
How will that improve air safety? Whether the crew increased or decreased the aircraft's performance, what matters is that everyone survived without any life-threatening injuries. Seems pretty hard to improve on that result.
(And why are we discussing BA038 on this forum anyway?)
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Go around manual power was required on both of these incidents. One aircraft couldn't produce thrust, one could. How are these two incidents similar? One was going to crash no matter what and the other needed manual thrust to go around when the RA malfunction retarded the throttles at a fairly high altitude.