TAM A320 crash at Congonhas, Brazil
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Originally Posted by Rippa
And once again, that's why I think something else (unannounced failure) happend last week.
Originally Posted by bomarc
when all shakes out, the lack of grooving, the probable lack of crowning, some unknown fault with the plane may all play a part.
I agree with you, Rippa... it needed one more thing, and probably only one, to turn a somewhat tricky landing into a disaster. Let's truly hope we will find out what it was.
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You could almost say: "now what has that to do with the price of lawnmowers?".....
I thought that, so far, ATC was not really involved at all.
I thought that, so far, ATC was not really involved at all.
ATC wasn't directly involved but after the Cindacta I and Cindacta IV failures, the ATC go-slow, and endless delays and mayhem the JJ accident was the last straw. Someone had to go, and I suspect Pires was first in line.
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Originally Posted by TwoOneFour
Someone had to go, and I suspect Pires was first in line.
Just think twice before you take an airline ticket to Brazil.
Bomarc -re runway check shortly before. I understand Brazilian press reporting this check was only done visually as the usual measuring equipment not used for some reason. Perhaps Rippa could confirm. The instruction to TAM pilots not to land at CGH if they think unsafe is clearly compromised if the reports of runway state cannot be relied upon.
The oft quoted Infraero suggestion that the runway was safe because other a/c managed to stop is ludicrous. An unsafe condition will not result in a catastrophe on every occasion. Also, rain,drainage,wind,landing weights etc are not constants, and there should always remain a margin for error, particularly where the consequences of overrun will be disastrous and where there had been enough near disasters to warn even the thickest skulls of the consequences.
The oft quoted Infraero suggestion that the runway was safe because other a/c managed to stop is ludicrous. An unsafe condition will not result in a catastrophe on every occasion. Also, rain,drainage,wind,landing weights etc are not constants, and there should always remain a margin for error, particularly where the consequences of overrun will be disastrous and where there had been enough near disasters to warn even the thickest skulls of the consequences.
Last edited by Max Tow; 25th Jul 2007 at 23:06.
Reverse or no reverse.
I have sympathy with the view that suggests banning the use asymmetric reverse, but we might just as well fix the issues with the runway – short, ungrooved, etc.
An accident usually consists of a series of apparently unrelated issues, all of which are necessary, but the absence of any one could prevent it. Thus, the debate is of which ‘one’ to fix - runway vs reverse, (or in the extreme, fix the human element).
I recall a UK study several years ago looking at the BAe146 overrun rate vs other large regional aircraft. The 146 (no thrust reverse) faired poorly against the 737 in UK/Europe, but the difference elsewhere was less. One hypothesis was that the operators of 737 (and similar types) relied on reverse to prevent an overrun in normal operations, i.e. they exceeded the normal safety margins and could have overrun except for reverse. This suggests that a crews’ behaviour was more risky when there was another safety layer available to them.
In my experience, 146 pilots had a greater awareness of landing distance and touchdown speeds than other regional operators, yet both operated into relatively short runways (I exclude LCY; there was a separate study there which showed a consistent performance). However, both groups had weakness in knowledge of the hazards of wet / contaminated operations and the problems of tailwinds; I think this resulted in a UK CAA publication – AIC ?
Looking at a wider spectrum of accidents, the HF contribution dominates and is a common theme, which would add strength to an argument to ‘fix the human’. However, this option is judged by eminent researchers as either ineffective or impossible in the majority of operational situations (one might ask why we teach CRM). James Reason et al, proposed fixing the organisation or system aspects which would provide a more effective defence. Most organisational / system issues involve human activity, but these are in less stressful situations, where the people should have more time to think about the safety problems, providing there is willingness, knowledge, and ability.
A more practical solution would be a broad front approach including more effective CRM (the thinking bits), CRM for managers, and improved technical knowledge for everyone.
In this thread, many posters ‘could not believe that people would … etc’, which of course is the fundamental aspect of error (we don’t believe that it will happen to us), but people do and will continue to make errors; it depends mostly on the situation.
Thus for the situation – technical aspects perhaps; more emphasis should be on touchdown speed and position, runway condition, wind, and aircraft handling, and how these are detected and assessed. The aircraft handling point goes full circle, handling procedures in non normal situations involve HF, how do we remember to change behaviour with one reverse MEL’d or when handling from a different seat?
There were many precursors to this accident, warning signs that were not noticed or not reported. These too are HF issues; regulation, motivation or just laziness … which is an HF issue anyway.
What do we fix? All of the above.
An accident usually consists of a series of apparently unrelated issues, all of which are necessary, but the absence of any one could prevent it. Thus, the debate is of which ‘one’ to fix - runway vs reverse, (or in the extreme, fix the human element).
I recall a UK study several years ago looking at the BAe146 overrun rate vs other large regional aircraft. The 146 (no thrust reverse) faired poorly against the 737 in UK/Europe, but the difference elsewhere was less. One hypothesis was that the operators of 737 (and similar types) relied on reverse to prevent an overrun in normal operations, i.e. they exceeded the normal safety margins and could have overrun except for reverse. This suggests that a crews’ behaviour was more risky when there was another safety layer available to them.
In my experience, 146 pilots had a greater awareness of landing distance and touchdown speeds than other regional operators, yet both operated into relatively short runways (I exclude LCY; there was a separate study there which showed a consistent performance). However, both groups had weakness in knowledge of the hazards of wet / contaminated operations and the problems of tailwinds; I think this resulted in a UK CAA publication – AIC ?
Looking at a wider spectrum of accidents, the HF contribution dominates and is a common theme, which would add strength to an argument to ‘fix the human’. However, this option is judged by eminent researchers as either ineffective or impossible in the majority of operational situations (one might ask why we teach CRM). James Reason et al, proposed fixing the organisation or system aspects which would provide a more effective defence. Most organisational / system issues involve human activity, but these are in less stressful situations, where the people should have more time to think about the safety problems, providing there is willingness, knowledge, and ability.
A more practical solution would be a broad front approach including more effective CRM (the thinking bits), CRM for managers, and improved technical knowledge for everyone.
In this thread, many posters ‘could not believe that people would … etc’, which of course is the fundamental aspect of error (we don’t believe that it will happen to us), but people do and will continue to make errors; it depends mostly on the situation.
Thus for the situation – technical aspects perhaps; more emphasis should be on touchdown speed and position, runway condition, wind, and aircraft handling, and how these are detected and assessed. The aircraft handling point goes full circle, handling procedures in non normal situations involve HF, how do we remember to change behaviour with one reverse MEL’d or when handling from a different seat?
There were many precursors to this accident, warning signs that were not noticed or not reported. These too are HF issues; regulation, motivation or just laziness … which is an HF issue anyway.
What do we fix? All of the above.
Re runway check (1mm water)
1mm may be safe on a good runway surface, but a simple check/measurement has little correlation with braking effectiveness on a poor or ungrooved surface. Furthermore, the definition of contaminated includes the % of runway covered, but this too does not guarantee that the aircraft will stop. All of these measurements and definitions are guidelines, generally in areas of operation that are technically ill-defined, and where the certification / operational regulations assume that the crew will compensate for the lower safety margins that the regulators allow, but rarely inform the operators about.
Many of the aspects in and around these problems are covered in Managing the Threats and Errors during Approach and Landing.
A good point made on slide 26 is in the comparison between wet grooved and ungrooved runways for the same speed. The comparison results in the complete range of ICAO reporting codes from ‘wet’ (Good, ICAO 5) to ‘contaminated / flooded’ (Nil, ICAO 1 – even ‘unreliable); thus 1mm could easily be nil/unreliable.
Perhaps we should treat any measurement on an ungrooved runway as ‘unreliable’.
Also be aware of concrete runways as these, either grooved or ungrooved, have poor braking conditions in comparison with well-drained tarmac.
1mm may be safe on a good runway surface, but a simple check/measurement has little correlation with braking effectiveness on a poor or ungrooved surface. Furthermore, the definition of contaminated includes the % of runway covered, but this too does not guarantee that the aircraft will stop. All of these measurements and definitions are guidelines, generally in areas of operation that are technically ill-defined, and where the certification / operational regulations assume that the crew will compensate for the lower safety margins that the regulators allow, but rarely inform the operators about.
Many of the aspects in and around these problems are covered in Managing the Threats and Errors during Approach and Landing.
A good point made on slide 26 is in the comparison between wet grooved and ungrooved runways for the same speed. The comparison results in the complete range of ICAO reporting codes from ‘wet’ (Good, ICAO 5) to ‘contaminated / flooded’ (Nil, ICAO 1 – even ‘unreliable); thus 1mm could easily be nil/unreliable.
Perhaps we should treat any measurement on an ungrooved runway as ‘unreliable’.
Also be aware of concrete runways as these, either grooved or ungrooved, have poor braking conditions in comparison with well-drained tarmac.
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MaxTow said: "The oft quoted Infraero suggestion that the runway was safe because other a/c managed to stop is ludicrous. An unsafe condition will not result in a catastrophe on every occasion."
While the runway and the airport may not have been truly "safe", we still need to figure out why literally hundreds, indeed thousands, of previous flights managed to stop on that very same runway while this particular airplane did not. CGH may well have been an accident waiting to happen, but what made it happen to this plane, on this landing.
While the runway and the airport may not have been truly "safe", we still need to figure out why literally hundreds, indeed thousands, of previous flights managed to stop on that very same runway while this particular airplane did not. CGH may well have been an accident waiting to happen, but what made it happen to this plane, on this landing.
Christiaan J
Think twice before going to Brazil, yes. Think three times before buying a domestic ticket, yes again. But … “equally incompetent” shows a bit of the prejudgement trap we’re all guilty of sometimes.
No argument re the departing defense minister’s lack of effectiveness. The new man, Nelson Jobim, does though have a reasonable track record for getting things done in the previous government. I’m rather surprised but am keeping an open mind. He’s reportedly been given carte blanche so perhaps there’s the faintest chance the structure will change. Right now it’s far too early to to say anything other than that the bottom of the pit has almost surely been reached and that from here forward anything should be an improvement. And that a few more political heads will roll, perhaps not immediately but in the next few weeks, to be replaced with more experienced/technical ones. Again, let's wait and see: we have little other options.
Back to the thread, it would seem that the talking heads on Globo and other tv channels are all focussed on Pprune and, in particular, the scenario 4PH introduced in post #424.
Think twice before going to Brazil, yes. Think three times before buying a domestic ticket, yes again. But … “equally incompetent” shows a bit of the prejudgement trap we’re all guilty of sometimes.
No argument re the departing defense minister’s lack of effectiveness. The new man, Nelson Jobim, does though have a reasonable track record for getting things done in the previous government. I’m rather surprised but am keeping an open mind. He’s reportedly been given carte blanche so perhaps there’s the faintest chance the structure will change. Right now it’s far too early to to say anything other than that the bottom of the pit has almost surely been reached and that from here forward anything should be an improvement. And that a few more political heads will roll, perhaps not immediately but in the next few weeks, to be replaced with more experienced/technical ones. Again, let's wait and see: we have little other options.
Back to the thread, it would seem that the talking heads on Globo and other tv channels are all focussed on Pprune and, in particular, the scenario 4PH introduced in post #424.
Just to be a devil's advocate (my speciality) including tongue in cheek but:
What;s broke to fix regarding the runway?
Sure we could all say if there was more margin, like a longer runway, less water etc. But in the end there will still be another similar accident with a different runway.
All we do in this business is to fix broken things, or add improvements to increase capability, including longer runways for heavier planes. If the runway is legal, there is nothing to fix. If you want to add margin to the runway, it will just get used by bigger planes in the end, like the rest of the world would do.
Or do we want the regulations changed affecting the whole world?
Before we start calling for changes against some specific ingredient of this accident we better also have some idea against what standards
What;s broke to fix regarding the runway?
Sure we could all say if there was more margin, like a longer runway, less water etc. But in the end there will still be another similar accident with a different runway.
All we do in this business is to fix broken things, or add improvements to increase capability, including longer runways for heavier planes. If the runway is legal, there is nothing to fix. If you want to add margin to the runway, it will just get used by bigger planes in the end, like the rest of the world would do.
Or do we want the regulations changed affecting the whole world?
Before we start calling for changes against some specific ingredient of this accident we better also have some idea against what standards
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Max Tow: thanks for the clarification on the method of runway checking...pretty weak to me!
ALF: Oddly enough, I've flown both the 146 and 737 and I always wished for thrust reverse on the BAE146...not because the plane needed it...I flew it into 4000some odd foot runways and was quite pleased to stop in 1800 feet without over doing the brakes...but the runways were very dry.
With the low noise profile, it would have been perfect for KDCA (146) except on snowy/wet nights...that scenario without TR was of concern.
Taking chances in normal ops with TR is a fine comment and indicates a real understanding of the practical vs. theoretical aspects of airline flying.
ALF: Oddly enough, I've flown both the 146 and 737 and I always wished for thrust reverse on the BAE146...not because the plane needed it...I flew it into 4000some odd foot runways and was quite pleased to stop in 1800 feet without over doing the brakes...but the runways were very dry.
With the low noise profile, it would have been perfect for KDCA (146) except on snowy/wet nights...that scenario without TR was of concern.
Taking chances in normal ops with TR is a fine comment and indicates a real understanding of the practical vs. theoretical aspects of airline flying.
RobertS975, There are almost certainly specific aspects of this accident that would answer why this flight overran and others did not. However, a simple statistical review of operations on a wet runway with the same type, wt, etc, would show a spread of landing distances. This is normal operation and why safety margins are applied (factored landing distances) – a principle of being safe, apply a margin.
On a wet runway, particularly ungrooved, the spread of landing distance could increase very quickly with small, seemingly insignificant changes in the conditions e.g. a small change in wind direction that prevents water drainage, changing the runway from wet to flooded.
lomapaseo, I think that the general changes called for were those applying to human behaviour – which is difficult.
‘World standards’ – this is one of the many problems in the industry. Generally the main regulators are in agreement for the certification aspects of wet / dry runways, but the systems diverge with ‘contaminated’ and the operational application of the rules. Note the Chicago Midway accident and the weak FAA response re verifying runway condition before landing vs the European ‘contaminated ops’ rules. (The FAA does note the European position but only as guidance).
Safety margins are open to operator judgement – safety management. A survey of this runway may well have concluded a reduced level of safety (judgement), but who would be the first operator to add a margin?
Well done to those pilots who don’t land in the wet (good safety margin), but why don’t the managers support this action – lack of personal standards?
On a wet runway, particularly ungrooved, the spread of landing distance could increase very quickly with small, seemingly insignificant changes in the conditions e.g. a small change in wind direction that prevents water drainage, changing the runway from wet to flooded.
lomapaseo, I think that the general changes called for were those applying to human behaviour – which is difficult.
‘World standards’ – this is one of the many problems in the industry. Generally the main regulators are in agreement for the certification aspects of wet / dry runways, but the systems diverge with ‘contaminated’ and the operational application of the rules. Note the Chicago Midway accident and the weak FAA response re verifying runway condition before landing vs the European ‘contaminated ops’ rules. (The FAA does note the European position but only as guidance).
Safety margins are open to operator judgement – safety management. A survey of this runway may well have concluded a reduced level of safety (judgement), but who would be the first operator to add a margin?
Well done to those pilots who don’t land in the wet (good safety margin), but why don’t the managers support this action – lack of personal standards?
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Not sure how to say this but this terrible accident is at least caused the dissemination of a lot of good information. It also appears that for whatever reason, spoilers may not have been deployed.
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AB Vs B
Have been reading a lot of discussion from B types about AB. Firstly, the B types need to grow up to technological advances and learn the process of automation. First the facts.
In 320, the ECAM memo for landing will tell u well before landing if your configuration is not correct. That avoids landing without wheels, flaps, spoilers etc.
Secondly, as you are flaring, loud shouts of retard retard start which end only after you bring TLs from clb gate to idle gate. Once that happens, your spoilers, aurobrakes etc are ready for operation. if u dont bring them to idle, system assumes, u dont wanna land. If you cant do that action too (bring TLs to idle), then you shouldnt be in 320 cockpit. This is the same action action which u do on almost all conventional aircraft.
Thirdly, after touch down, you need to bring the TLs to retard if you require them, which in all practical cases, you and I do require. In case, one reverser is inop, like in this case AND has been inhibited, you can still bring bOTH TLs to full retard and the available reverser will deploy. Contrary to the B types, there is not a significant yawing action with one reverser deployed and even on wet runways it is easily controllable even with a crosswind of lets say upto 20 knots.
Problem could occur if you DO NOT carry out the action of bringing TLs to idle even with loud calls of retard retard. At this stage, the auto thrust cuts off and the engine will spool up to the thrust set by TL.
There can be a lot of uses of automation and users need to know how to use it rather than fight it or try to find ways to go round it.
I have not seen anyone operating the 320, having any problem with this procedure. infact it is so convenient.
In 320, the ECAM memo for landing will tell u well before landing if your configuration is not correct. That avoids landing without wheels, flaps, spoilers etc.
Secondly, as you are flaring, loud shouts of retard retard start which end only after you bring TLs from clb gate to idle gate. Once that happens, your spoilers, aurobrakes etc are ready for operation. if u dont bring them to idle, system assumes, u dont wanna land. If you cant do that action too (bring TLs to idle), then you shouldnt be in 320 cockpit. This is the same action action which u do on almost all conventional aircraft.
Thirdly, after touch down, you need to bring the TLs to retard if you require them, which in all practical cases, you and I do require. In case, one reverser is inop, like in this case AND has been inhibited, you can still bring bOTH TLs to full retard and the available reverser will deploy. Contrary to the B types, there is not a significant yawing action with one reverser deployed and even on wet runways it is easily controllable even with a crosswind of lets say upto 20 knots.
Problem could occur if you DO NOT carry out the action of bringing TLs to idle even with loud calls of retard retard. At this stage, the auto thrust cuts off and the engine will spool up to the thrust set by TL.
There can be a lot of uses of automation and users need to know how to use it rather than fight it or try to find ways to go round it.
I have not seen anyone operating the 320, having any problem with this procedure. infact it is so convenient.
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@nada1234
Good morning,
Please stop this A v B Story, my B retards by itself passing 20 ft and i can watch the T/L coming back.
So far about automatisation, "from CLB to idle during landing"
best regards
Please stop this A v B Story, my B retards by itself passing 20 ft and i can watch the T/L coming back.
So far about automatisation, "from CLB to idle during landing"
best regards
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Regarding the state of the runway/airfield, I feel any blame should lie with the apparent lack of dissemination of information. Whether or not the 'slippery' nature of a wet 35L WAS known to airlines we do not seem to have established. I would argue that responsibility for whether or not and how you operate into such an airport should be left with the airline and ultimately the Captain. Given knowledge of the apparent condition of a wet 35L I would have hoped that landing weight/crosswind limitations would have been imposed, along perhaps with additional MEL restrictions, and given this 'odd' phenomonen of what appears to be the occasional incorrect AB throttle handling technique (reverser out) I would have expected this to have been highlighted well before through the safety process, especially where the apparent result of such mishandling can be so catastrophic. Having an engine run to 'Climb' power during landing is going to cause tears, even on a long dry runway.
It would seem that there is a gap to be filled in teaching AB handling. As with any new system, especially a software driven one, 'bugs' are found and need to be dealt with, either by modification or by crew training as happened with the early AB accidents, when the learning curve was very steep. As 'dreamland' says in #534, maybe we have now reached that stage?
It would seem that there is a gap to be filled in teaching AB handling. As with any new system, especially a software driven one, 'bugs' are found and need to be dealt with, either by modification or by crew training as happened with the early AB accidents, when the learning curve was very steep. As 'dreamland' says in #534, maybe we have now reached that stage?
BOAC: Your suggestion of responsibility for wet/otherwise degraded runway ops being left with airline & Captain assumes that they receive an adequate and accurate flow of data from the airport operator. A chap inbound to CGH on a dark,wet evening has little else upon which to rely.
Two questions:
1) Is it correct to infer from earlier posts from Dream Land that the AB procedure for applying reverse on a locked out u/s reverser was amended recently (before "don't", now "do")?
2) Has there been any explanation of the previous day's non-fatal runway excursion (Pantanal)?
Two questions:
1) Is it correct to infer from earlier posts from Dream Land that the AB procedure for applying reverse on a locked out u/s reverser was amended recently (before "don't", now "do")?
2) Has there been any explanation of the previous day's non-fatal runway excursion (Pantanal)?
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Indeed, Max - hence sentence 2.
Two more things come to mind:-
1) I am quite frankly amazed that the relevant MEL called for an addition of only 55m for ALL runway conditions reverser out. I would ask that ALL regulatory bodies review ALL MELs (yes - Boeing as well
) to ensure a sensible figure. It can be ZERO for normal ops and as with the 737, NO operation on contaminated/slippery or at least +50% of the LDR for 'slippery'. I am certain the unfortunate TAM crew had done their calculations correctly IAW their MEL etc, but had this been in place this accident might not have occurred. (Which takes us back to promulgated runway state/braking action, of course.)
2) I sense a little confusion in some of the posts above (hopefully not from any commercial pilots) regarding the word 'contaminated'. It has a meaning in English. In a/c performance terms strict depths of contaminant are required (typically >3mm of water) before a runway is 'contaminated', and just surface water in itself does not necessarily qualify, although see post #458 by 'Few Cloudy' which is extremely relevant.
Two more things come to mind:-
1) I am quite frankly amazed that the relevant MEL called for an addition of only 55m for ALL runway conditions reverser out. I would ask that ALL regulatory bodies review ALL MELs (yes - Boeing as well
) to ensure a sensible figure. It can be ZERO for normal ops and as with the 737, NO operation on contaminated/slippery or at least +50% of the LDR for 'slippery'. I am certain the unfortunate TAM crew had done their calculations correctly IAW their MEL etc, but had this been in place this accident might not have occurred. (Which takes us back to promulgated runway state/braking action, of course.)2) I sense a little confusion in some of the posts above (hopefully not from any commercial pilots) regarding the word 'contaminated'. It has a meaning in English. In a/c performance terms strict depths of contaminant are required (typically >3mm of water) before a runway is 'contaminated', and just surface water in itself does not necessarily qualify, although see post #458 by 'Few Cloudy' which is extremely relevant.
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Just a short remark to yaw moment on a dry RWY,
I flew the day after the accident to RHO in a 738. When I took the AC from tec stuff, they told me T/R 2 is U/S. I got kind of a strange feeling, but off we went. At destination just for the sake of understanding the accident a little better we applied full reverse thrust on # 1. No yawing at all. I took my feet off the rudders for a while to check what happens. Nothing. Just rolled down the center line, ok, the RWY was dry. (No NWS input either)
I flew the day after the accident to RHO in a 738. When I took the AC from tec stuff, they told me T/R 2 is U/S. I got kind of a strange feeling, but off we went. At destination just for the sake of understanding the accident a little better we applied full reverse thrust on # 1. No yawing at all. I took my feet off the rudders for a while to check what happens. Nothing. Just rolled down the center line, ok, the RWY was dry. (No NWS input either)