TAM A320 crash at Congonhas, Brazil

[alemaobaiano]

While doing so found another site where an A320 returned to the gate because the TL would not control the engine. I know, that could never happen.

http://www.airnig.co.uk/a320.htm

Is that the one? An unofficial, unverified, anonymous email comment from 1995?

ab

[SR71]

TripleBravo,

Autobrake LO = 1.7 m/sē
Autobrake MED = 3 m/sē

Average decel between 48:29 and 48:36 =~ 0.6 m/sē
Average decel between 48:36 and 48:50 =~ 1.2 m/sē

Average decel, ~55T, 146kts touchdown, WET, with autobrake MED, no spoilers, No 1 max reverse, No 2 (EPR = 1.08) =~ 1.5 m/sē (cf. Transavia 536 Report, Pg 143)

Average decel, ~55T, 146kts touchdown, 1/4" water, with autobrake MED, no spoilers, No 1 max reverse, No 2 (EPR = 1.08) =~ 1.1 m/sē (cf. Transavia 536 Report, Pg 143)

(Note that the Transavia report suggests that if you do not touch the brakes, in the config the TAM pilots were in, they would have got no decel at all, regardless of the runway state. This seems to be the case between 48:27-29)

Time between nose gear touch down and first brake application =~2 secs.

To me its looking like the pilots were actually pretty swift in getting on the brakes, albeit not to the point where their full potential was exploited. From where I sit, the application of max manual braking would not have prevented an over-run, in their particular config, but it would have been close(r).

I note also 1/4" of water is worse than 1/2" of water in terms of its effect on LDR's.

I'm not sure what Airbus SOP is, but we normally cancel reverse at ~60kts, so I contend that they would only have needed to reduce the speed to a value approaching this for them to have had another chance to identify (if they hadn't earlier) the unusual TL position(s) and taken some further action to ameliorate the situation.

[TopBunk]

I haven't posted on this thread for about 50 pages because a lot of the arguments just go round in circles!

In any accident there are primary causes and contributory factors, imho.

In this case the primary cause was the failure of the pilots to retard both thrust levers to idle, in that if they had completed that very basic task, then whatever followed may have been avoided, but without that action the accident was guaranteed.

I would expect in the fullness of time, that the runway surface will emerge as a significant contributory factor.

There may also be recommendations re Runoff areas, pilot interface etc, but, nonetheless, the root cause was the failure to retard the thrust levers, which should be second nature to any pilot.

[I speak as someone who has considerable hours on both Airbus and Boeing product - just to clarify my credentials]

[flyer146]

Lemurian wrote p82 :
2. An important call-out is missing on the CVR : " No DECEL !", indicating the auto-brake isn't functioning as set.

I do not agree with you Lemurian.
To my understanding (and at least on A330/340), the decel green light will only come if the selected deceleration rate is effectively achieved.
No green light not meaning that the system is not functionning but merely meaning that the selected decel rate is not achieved (ref FCOM airbus).
This would be quite usual on slippery runways for example and would not be considered (alone) as a malfunction of the autobrake at first glance by the crew (probably even expecting not to see this light right away after landing on this difficult/slippery landing)! Correct me if I am wrong...

Human factors, aircraft design, weather, airport, etc... etc... etc... as in all other accidents have played a role in this tragedy and have to be analysed.

To my opinion, leaving one of the thrust lever in CLB detent during the roll out and not noticing it is a real possibility due to the focussing on the reverser problem by the PF. Although we all have learned since basics not to do so and the SOP's/MEL's being clear, it could be easily done I think in this machine even, unfortunately, by an experienced pilot.

What about the cockpit lighting at the moment of the crash ? Pedestal lighting ? I remember how an unbalance in the cockpit lighting led to a go around on one of my flights a couple of years ago. One switch controlling a lot of panels but with a big unbalance between them and you could be looking for the correct lever/switch or it could just be "hidden" of your normal scan/"view" without that you especially notice it ! And in a stress situation : even worse...(even if PF mistake ; would PNF have a chance to detect this uncorrect TL position ??? don't think so...)

Did you ever noticed how "dark" a cockpit/pedestal/TL's can be at night ? And the accident happend at night, right ?
Also, the thrust levers are "small"/short length and thus for the same angle, the displacement gives quite a reduced viewable effect.
TL's are black color in this aircraft.
No chance to notice this in the given weather conditions/runway length were the PNF having seen that something was wrong and unable to solve the problem was certainly rapidly looking outside trying to help the PF to avoid the worse...

Talking about the airbus design here above : these are facts ! Now, did they play a negative role in this accident, that's another story! Maybe this same design helped a lot of crew in difficult situations as well and you won't ever know this because not reported !
Would another configuration/design be better : long studies have probably been done before design already and prove that it's not the case. Remember, it's all about compromise...and will never be "PERFECT" cos it's human.

Nevertheless, we'll ALL have to learn something from this : that's the only thing important : let's all learn something so that the same occurance does not happen again. Let's improve our awareness, our training and of course let's improve the design if no other "too negative"effects are induced by the modifications.......... !

Flyer146

[Right Way Up]

Flyer146,
What Lemurian said is quite correct. The autobrake was not providing the decleration that was set/required! You are also correct that the autobrake could have been working but because of a slippery runway could not provide the required deceleration. However the "NO DECEL" is a standard call and was missed out! Maybe the announcement of "No spoilers" & "No decel" would have woken the PF to the real reason or prompted him to go-around.

[marciovp]

Boeing 777 and 787

The editor of "The Controller" a magazine of the IFATCA (International Federation of Air Traffic Controllers ASSNS) in the June Issue said:
" It is all about trusting technology, similar to Airbus and Boeing pilots(People forget that the 777 and the coming 787 are using almost the same advanced automation technology as Airbus)"
Is that so?

[PBL]

Originally Posted by TopBunk

In any accident there are primary causes and contributory factors

TopBunk,

I believe the ICAO agreement requires countries to identify a "probable cause" of an accident. Since most investigators realise that there is almost never just one cause of an accident, many jurisdictions now speak of "probable cause and contributing factors", and I understand the Canadians don't prioritise at all.

Most top researchers in accident causality judge that prioritising causes, as it is now performed by investigating authorities, is a matter of ranking causes according to inexplicit criteria which may be extraneous to causally explaining the accident.

Could you give your criteria for selecting "primary cause"?
Could you say, for example, why you would not consider the length of the runway as a "primary" cause? It does satisfy the Counterfactual Test, just as your chosen "primary" cause does. Why do you pick one but not the other?

One selection criterion could be: we reckon relative persistence of the phenomenon throughout successful operations counts for a lower priority. The length of the runway certainly fits this criterion for deselection - it has been used in many successful landings, including one just before the accident. So we would reckon that priority as low (as, for example, the earth bank at the end of the runway was not reckoned as a causal factor in the Warsaw report, even though it was directly causal in the two deaths that occurred), and the pilots' (in)actions in not reducing TL to idle as high.

The problem with that criterion is that it allows unsafe situations that persistently recur to achieve low priority automatically. For example, AA was warned in 1997 by AI, Boeing and the FAA in a joint letter that teaching use of rudder in their advanced piloting course could possibly lead to structural failure of an aircraft. Which happened in 2001. So this persistent phenomenon which some considered unsafe would be discounted as a causal factor according to the criterion above.

An obvious, and obviously not scientifically justifiable, selection criterion is: we discount phenomena which were "our" responsibility, and we emphasise phenomena which were the responsibility of others. This is why, for example, in many countries the investigating body is structurally independent of other government authority, for then there is not seen to be the "our"-"their" distinction on which this criterion rests. Examples of this might be (1) Warsaw; (2) in the inquiry into AA587, the NTSB Chairman complained publically about persistent interventions by the two main organisations involved in the accident; (2) concerning the 2006 Amazon midair collision, there has been suggestion by some authorities that air traffic control is not a factor, although the behavior of individual controllers might have been, despite that the displayed altitude of the Legacy on the controllers' screens at CINDACTA-1 was different from the altitude at which it was actually flying. And the investigating body is a part of the same government organisation which has responsibility for air traffic control.

PBL

[PBL]

Originally Posted by marciovp

"...(People forget that the 777 and the coming 787 are using almost the same advanced automation technology as Airbus)"
Is that so?

In general terms, yes. And the companies providing some of the automation do so to both airframe manufacturers. However, the architectures of many of the systems are different. Cary Spitzer's book, Digital Avionics Systems: Principles and Practice, 2nd Edn., McGraw-Hill 1993, talks about the overall architectures of the A320 and the B777 FCSs in Chapter 7.

PBL

[Dani]

Sorry to disagree with PBL again, but TopBunk is again absolutely correct in his analysis.

The short runway is not a cause of the accident, it's a contributing factor. It's not even a secondary cause.

You can argue endlessly about slipperyness and deceleration aso, if there wouldn't have been this TL left in CLB, none of these contributing factors would have caused an accident. Please go through the performance calculation. The only primary cause that lead to this accident was therefore the TL. I would even go so far that he would have left a dry runway.

So if the TL for itself alone could lead to an accident, it's certainly a primary cause. And since he would have been most probably able to stop with both TL in reverse, the slipperyness was only a contributing factor.

I know it is very important for you to use the correct terms and to express yourself in a scientific language, but we are not scientist and we are here to search practicable findings for pilots. It would be nice to have a down-on-earth-approach about this.

I still cannot believe that some people here in this thread - after 100 pages! - don't see the most plausible reasons behind this tragedy.

Dani

[Right Way Up]

The reason the TL issue is a primary cause, but the slippery runway is only a contributary factor, is that whilst other aircraft that night landed on a slippery runway and did not crash, the only aircraft that did not retard the thrust levers did crash!

[Super VC-10]

Dani makes an interestin point -

You can argue endlessly about slipperyness and deceleration aso, if there wouldn't have been this TL left in CLB, none of these contributing factors would have caused an accident. Please go through the performance calculation. The only primary cause that lead to this accident was therefore the TL. I would even go so far that he would have left a dry runway.


Anyone done the maths?

[flyer146]

Right way up :

Maybe the announcement of "No spoilers" & "No decel" would have woken the PF to the real reason or prompted him to go-around.

Quite correct Right Way Up; (and as you say : maybe.)

Do you ever practice in the sim landings where you must decide to go-around when on the ground already ? Just for my info because I can tell you that for me the answer is : almost NEVER if not NEVER at all.
Don't you think we should practice this more and get some confidence in going around although wheels have touched concrete already ?
Don't we "commit us to STOP" once we touch the ground ?
Of course, we have to consider : if reversers are out, brakes applied, etc... but still, it would be nice to have some practice on this and see what is possible and what is not.
What are your opinions ?

Flyer146

[PBL]

Originally Posted by Right Way Up

The reason the TL issue is a primary cause, but the slippery runway is only a contributary factor, is that whilst other aircraft that night landed on a slippery runway and did not crash, the only aircraft that did not retard the thrust levers did crash!

That is certainly a potential criterion. It is related to the criterion in Mill's Method of Difference. Let's look at it further.

The same reasoning exonerates any features of the design of the A320 controls, for they have been used in millions of successful landings. Given the number of people on this thread who have been arguing that the design of the A320 controls was a major factor, it would seem that they are not using this criterion for identifying main factors.

Consider the accident to AA 587. The first officer's use of rudder to control yaw at other than low speed had been noted by others he had flown with, in successful flights. Lots of people have flown A300's without the fin separating. And lots of people have encountered wake turbulence, and yaw in turbulence, without their airplanes breaking. So it seems as if this criterion is not applicable to prioritising the factors in the AA 587 accident. So it doesn't apply everywhere.

In the Warsaw accident, people had landed A320s before carrying 20 kts over VRef (it was in the Ops Manual). And the pilots performed according to SOPs and the weather info from the tower and a Pirep. And people had landed before with outdated weather information. And people had landed before him. But the front had just gone through and the wind changed. Applying the criterion, the primary cause would then be the weather, and everything else is just "contributory".

In the Strasbourg (mont St.-Odile) accident, many crews had used the V/S / descent angle controls many times successfully, as well as not paying so much attention to each other and their tasks, so again there is no application of this prioritisation criterion.

In the midair collision in Überlingen, the particular difference between this and other TCAS encounters would be that one crew thought they were in conflict with two other aircraft and resolved the conflict in favor of the "phantom" rather than the real "intruder" (in TCAS parlance). And that happened because the controller misspoke once (advising of a conflict at 2 o'clock rather than the 10 o'clock on which they had a visual).

In the Cali accident, the particular difference would be that they were withing reception range of two NDBs with the same frequency and the same identifier (that is, though, not unique - the NTSB identified two other such situations worldwide).

In the Birgenair B757 accident off the Dominican Republic, again all the factors (INOP ASI, confused crew) were not particular to that accident, so again the criterion could not be applied to prioritise.

It should now be clear through these few examples that
* the proposed criterion does not always apply to prioritise causal factors, and
* in cases in which it does apply, there are apparently other prioritisation criteria which take precedence

So why would it be the predominant prioritisation criterion in the Congonhas case?

PBL

[Right Way Up]

Flyer146,
I believe the general sim routine is flawed. We think too much inside the box i.e. with set routines, that do not stretch our decision-making or imagination. There have been incidents where lives have been saved because the crew had used the spare time at the end of their last sim to practice an real "out of the box" emergency.

[filejw]

As I read all the posts about this accident I recall that at least twice in the sim when I was on the 320 pilots did not retard the TL from the climb detent in a TR inop scenario's. Result was never pretty dry or wet R/W as the A/C is a bit hard to handle with one engine full or part power and the other in reverse.

[Dani]

Quote from PBL:
So why would it be the predominant prioritisation criterion in the Congonhas case?

Because this predominant cause was so devastating that it broke their neck! That's why!

By the way: AA587: The malhandling of the FO's rudder was indeed the primary cause. Just because he did it before and survived doesn't mean that he always would get away with it. You are thinking very simplistic if you argue that touching a rudder, forgetting a thrust lever, misinterpreting weather aso is always the same. It always depends on how strong the mistake was and how it interacted with other, not predominant causes.

Do you want to argue that we shouldn't prioritize causes, i.e. looking at all not essential contributing factors with the same emphazis, even if their influence on the outcome was minor or even neglectable?

[PBL]

Originally Posted by PBL

So why would it be the predominant prioritisation criterion in the Congonhas case?

Originally Posted by Dani

Because this predominant cause was so devastating that it broke their neck!

Dani, you seem to be mixing up the two notions of *prioritisation criterion* and *cause*. I was asking about criteria. You respond with a comment about cause.

I don't think it makes much sense to discuss this unless we can agree to keep the concepts straight.

PBL

[TripleBravo]

It always depends on how strong the mistake was

Where do you know what is strong and what not? Sorry to say, but what you said is a tautology. Your input serves as a measure in order to prove the input... that doesn't work out. I believe I understand your feelings, but your conclusion is not entirely derived by logic, rather feelings. As I understand, PBL is looking for the pure logical approach to distinguish between minor and major factors - and the TL in CLB cannot be sorted out to be "primary" by applying statistics or mathematical formulae.

BTW, it is not correct, that TAM 3054 was the only airplane that had problems with the length of the runway. There were problems, e. g. just the day before. Had the runway been longer, say 2400 meters (see my calculation some posts above), they would live today. To put it in your words: "Because this predominant cause was so devastating that it broke their neck! That's why!"

[lomapaseo]

PBL

I believe the ICAO agreement requires countries to identify a "probable cause" of an accident

I sure hope that you can't find anything written to support the above.

The problem that I have with a finding of Probable cause is that it attracts most of the attention to a single item that quite often does not lend itself to responding to a practical solution. The idea behind investigating in the first place is to determine any holes in the swiss cheese whereby practical (effective and quick) corrective actions can be applied to make it less likely that the accident will be repeated.

[PBL]

Originally Posted by Super VC-10

Anyone done the maths?

The data probably aren't there for us to answer the question how long it takes to stop an A320 at 62.7 tons from 70 kts with one engine on reverse thrust and the other at 1.2 EPR with a moderate dry-runway coefficient of friction. AI probably has the models, and I would guess someone with access to good models and a supercomputer may well try to do so in order to see how much the runway surface condition may have contributed to the overrun.

However, it is easy to say what acceleration they would have to have achieved in order to stop from a 70-kt touchdown. Acceleration of -1.5 m/s/s gives a stopping distance of about 1634 m, and acceleration of -1.4 m/s/s gives a stopping distance of 1750 m.

So if you have them planning manual braking, getting WoW at 1650 m remaining and taking a second to react with manual brakes, then they would have needed to achieve about 20% more deceleration than they actually did achieve with manual braking in order to stop within the asphalt.

I don't know whether that will turn out to have been possible, but from what we know at this point I consider it plausible that that could have been achieved on a dry runway.

PBL