TAM A320 crash at Congonhas, Brazil
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GearDown&Locked,
I agree with you, that in so many areas, automation has made flight safer, the pilot is still there to override in the rare event that the automatic systems fail.
But my statement about feelings in system design was concerning something entirely different:
that one system design should not be preferred over another, just because one designer feels the other system is inferior.
Bernd
I agree with you, that in so many areas, automation has made flight safer, the pilot is still there to override in the rare event that the automatic systems fail.
But my statement about feelings in system design was concerning something entirely different:
that one system design should not be preferred over another, just because one designer feels the other system is inferior.
Bernd
Last edited by bsieker; 9th Aug 2007 at 07:25.
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Dreamland, I guess the point was not having to fight automation logic that won't give you ground spoilers until it senses all the inputs required and the pilot cannot override this logic on the A320. By bubbers44
As far as misinterpretation of the MEL, it seems unlikely, both pilot's were very experienced, would be nice to hear from a TAM pilot.
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As far as misinterpretation of the MEL, it seems unlikely, both pilot's were very experienced, would be nice to hear from a TAM pilot.
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my guess is that they thought they were in their previous aircraft where it was absolutely important not to touch the faulty thrust lever in case of reverser fault. Otherwise nobody never ever would do such a thing.
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TP,
Yes. I think it is very unlikely.
But, according to Flight International, o sr. Filho is keeping that option open and he is leading the investigation, not I.
PBL
[PBL]
Or why this data might not represent true TLA, etc.
[TP]Assuming no prior ECAM warning about TLA, for the T/L to be moved to Idle while both TLA sensors indicate CL detent until impact (IIRC), would surely need simultaneous identical faults in each sensor?
And if there had been an ECAM warning FADEC would have selected Idle thrust on the ground.
Or why this data might not represent true TLA, etc.
[TP]Assuming no prior ECAM warning about TLA, for the T/L to be moved to Idle while both TLA sensors indicate CL detent until impact (IIRC), would surely need simultaneous identical faults in each sensor?
And if there had been an ECAM warning FADEC would have selected Idle thrust on the ground.
But, according to Flight International, o sr. Filho is keeping that option open and he is leading the investigation, not I.
PBL
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TP,
The last "retard" call was just before 18:48:23 and the #1 TL had started moving at 18:48:22. Pretty much simultaneous. WoW of left main gear is shown as taking one second from 18:48:23 until 18:48:24.
WoW is shown on right main gear already at :25. That at :26.3 that you thought might be the nosewheel is indeed the nosewheel.
At the previous landing by this crew in Porto Alegre, both thrust levers were moved simultaneously -> Idle -> Idle Reverse -> Reverse -> Idle Reverse -> Idle.
PBL
The last "retard" call was just before 18:48:23 and the #1 TL had started moving at 18:48:22. Pretty much simultaneous. WoW of left main gear is shown as taking one second from 18:48:23 until 18:48:24.
WoW is shown on right main gear already at :25. That at :26.3 that you thought might be the nosewheel is indeed the nosewheel.
At the previous landing by this crew in Porto Alegre, both thrust levers were moved simultaneously -> Idle -> Idle Reverse -> Reverse -> Idle Reverse -> Idle.
PBL
Last edited by PBL; 9th Aug 2007 at 07:55. Reason: Can't tell the difference between red and purple without my glasses
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PBL and overrun areas
Keep in mind that the runway does have a short overrun area (there is a displaced threshold), so the amount of tarmac is greater than that published. One can well imagine that things would have been different had manual braking been applied earlier. They would at least have gone off the end more slowly.
Sir, please do not confuse a displaced threshold for landing in the other direction, which is related to an obstacle, with the distance available for landing on 35L. The LDA for 35L was declared at the time of the accident in NOTAM J0362/07 (A) SBSP (B) 0704090001 (C) PERM (E) 35L LDA 1880M.
A look at Google Earth and use of the ruler function will show you that the distance from the threshold of Runway 35L to the end of the paved surface (and hence the start of the drop) is around 1880 metres.
The AIP here states that all ICAO Annex 14 runway physical requirements are met at the airport (AIP Brasil GEN 1.7 para 16).
The runway strip requirements at the end of a runway are given in ICAO Annex 14 Volume 1 paras 3.4.1 and 2 and requires a distance of at least 60 metres.
The runway end safety area requirements at the end of a runway are given in ICAO Annex 14 Volume 1 paras 3.5.1 to 3.5.3 which requires at least 90 metres and recommends 240 metres beyond the end of the runway strip.
Any logical implication that you make from the facts above relating to the validity of the statement in the AIP about Annex 14 compliance is purely your own deduction.
Kind regards and with the appropriate respect to PBL for the other areas of his work and conclusions,
Our Man.
Sir, please do not confuse a displaced threshold for landing in the other direction, which is related to an obstacle, with the distance available for landing on 35L. The LDA for 35L was declared at the time of the accident in NOTAM J0362/07 (A) SBSP (B) 0704090001 (C) PERM (E) 35L LDA 1880M.
A look at Google Earth and use of the ruler function will show you that the distance from the threshold of Runway 35L to the end of the paved surface (and hence the start of the drop) is around 1880 metres.
The AIP here states that all ICAO Annex 14 runway physical requirements are met at the airport (AIP Brasil GEN 1.7 para 16).
The runway strip requirements at the end of a runway are given in ICAO Annex 14 Volume 1 paras 3.4.1 and 2 and requires a distance of at least 60 metres.
The runway end safety area requirements at the end of a runway are given in ICAO Annex 14 Volume 1 paras 3.5.1 to 3.5.3 which requires at least 90 metres and recommends 240 metres beyond the end of the runway strip.
Any logical implication that you make from the facts above relating to the validity of the statement in the AIP about Annex 14 compliance is purely your own deduction.
Kind regards and with the appropriate respect to PBL for the other areas of his work and conclusions,
Our Man.
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that one system design should not be preferred over another, just because one designer feels the other system is inferior.
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hetfield asks
Because someone with access is putting them in the public domain, as they did with the CVR preliminary transcript last week, and we are discussing them.
(Isn't this obvious? Is this what the question was supposed to mean?)
PBL
How come preliminary FDR data of a serious accident are leaking to a public forum?
(Isn't this obvious? Is this what the question was supposed to mean?)
PBL
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Our Man,
thanks for the heads-up. I don't necessarily use Google Earth or Maps as my precision measuring instrument, but if one trusts it then that tarmac beyond the displaced threshold for 17R indeed seems to be included in the LDA for 35L.
[Comment added in editing] The JeppView Congonhas chart says that for landing 35L beyond the threshold there is 6168 ft / 1880 m usable length. The scale on the chart confirms this, as do measurements according to the scale on the Airport Description Chart available from http://www.flyvba.com.br
Your point about conformance with the ICAO Annex 14 is well taken!
PBL
thanks for the heads-up. I don't necessarily use Google Earth or Maps as my precision measuring instrument, but if one trusts it then that tarmac beyond the displaced threshold for 17R indeed seems to be included in the LDA for 35L.
[Comment added in editing] The JeppView Congonhas chart says that for landing 35L beyond the threshold there is 6168 ft / 1880 m usable length. The scale on the chart confirms this, as do measurements according to the scale on the Airport Description Chart available from http://www.flyvba.com.br
Your point about conformance with the ICAO Annex 14 is well taken!
PBL
Last edited by PBL; 9th Aug 2007 at 14:59.
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thanks for the heads-up. I don't necessarily use Google Earth or Maps as my precision measuring instrument
I try to give factual statements here, to minimise speculation. I try to provide some way that people can reference the facts where possible.
Google Earth is just a way that people can see the relevant distance and the threshold markings. It is a blunt but effective tool when considering significant distances such as the nautical mile length of the declared landing distance available and the runway strip size.
For the avoidance of doubt "Use of Google Earth for aeronautical data is not in compliance with ICAO Annex 14 Volume I, Chapter 2, Section 2.1 and Appendix 5."
I try to give factual statements here, to minimise speculation. I try to provide some way that people can reference the facts where possible.
Google Earth is just a way that people can see the relevant distance and the threshold markings. It is a blunt but effective tool when considering significant distances such as the nautical mile length of the declared landing distance available and the runway strip size.
For the avoidance of doubt "Use of Google Earth for aeronautical data is not in compliance with ICAO Annex 14 Volume I, Chapter 2, Section 2.1 and Appendix 5."
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Both reversers out procedure.
For the other human factors specialists considering how procedures are written, presented, interpreted etc...
For one reverser inop:
At landing
Before touchdown: Thrust levers 1 and 2... IDLE
After touchdown: Rev 1 and 2 ... MAX
For both reversers inop apply the following procedure:
Do not select thrust reversers
This is significantly different from saying in the both inop case:
before touchdown bring both thrust levers to idle
After touchdown confirm both levers idle.
Remember those at or near idle cases discussed earlier?
A question for those with A320 manuals to hand:
In the event of a hydraulic system fault when airborne, which has an implication for loss of a thrust reverser, do the procedures make a SPECIFIC reference to how the thrust levers should be handled on landing either within the hydraulic failure operational procedure pages or by reference to the exhaust operational procedures.
Discount.
For one reverser inop:
At landing
Before touchdown: Thrust levers 1 and 2... IDLE
After touchdown: Rev 1 and 2 ... MAX
For both reversers inop apply the following procedure:
Do not select thrust reversers
This is significantly different from saying in the both inop case:
before touchdown bring both thrust levers to idle
After touchdown confirm both levers idle.
Remember those at or near idle cases discussed earlier?
A question for those with A320 manuals to hand:
In the event of a hydraulic system fault when airborne, which has an implication for loss of a thrust reverser, do the procedures make a SPECIFIC reference to how the thrust levers should be handled on landing either within the hydraulic failure operational procedure pages or by reference to the exhaust operational procedures.
Discount.
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Reverse procedures
DiscountInvestigator.
The airborne abnormal procedures do not mention any special thrust lever handling with regards to a reverser not being available.
REV 1 (and/or 2) INOP will be listed on the status page.
Any "handling tecnique" with regards to thrust lever will only be given in case of a reverser acting up while airborne, so to protect you from an effect like Lauda B767 encounterd in 1991.
The airborne abnormal procedures do not mention any special thrust lever handling with regards to a reverser not being available.
REV 1 (and/or 2) INOP will be listed on the status page.
Any "handling tecnique" with regards to thrust lever will only be given in case of a reverser acting up while airborne, so to protect you from an effect like Lauda B767 encounterd in 1991.
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Statistics
PBL,
Your comments are very well informed, however I disagree strongly on some of your statistic conclusions.
You calculate that 3 accidents in 54 million landings is not bad for the A-320 system, roughly 1 accident per 17 million landings.
However, if you consider that on the average, the very reliable Airbus will only fly one per thousand flights with a reverser de-activated, there has been 1 accident per 17.000 flights with T/R de-activated, arithmatically speaking. A disturbing rate, I would say.
Moreover, those accidents had nothing to do with degraded landing performance caused by T/R de-activated, they all happened as a result of mishandling the thrust lever of the engine with the thrust lever de-activated. All with Autothrust active untill the flare. A serious issue from Man Machine interface standpoint, I would also say.
Your comments are very well informed, however I disagree strongly on some of your statistic conclusions.
You calculate that 3 accidents in 54 million landings is not bad for the A-320 system, roughly 1 accident per 17 million landings.
However, if you consider that on the average, the very reliable Airbus will only fly one per thousand flights with a reverser de-activated, there has been 1 accident per 17.000 flights with T/R de-activated, arithmatically speaking. A disturbing rate, I would say.
Moreover, those accidents had nothing to do with degraded landing performance caused by T/R de-activated, they all happened as a result of mishandling the thrust lever of the engine with the thrust lever de-activated. All with Autothrust active untill the flare. A serious issue from Man Machine interface standpoint, I would also say.
So the aircraft crashed because the right thrust lever was not pulled back to idle by the flight crew.
This was due to: (one or more answers may be correct)
A. Design flaws by Airbus, which may cause confusion and/or ambiguities with respect to thrust lever handling upon touchdown
B. Inadequate training by TAM, which resulted in substandard technical knowlegde of aircaft systems and/or incorrect flight techniques
C. Very good training by TAM but despite this, usage of incorrect flight techniques
D. Both A and B
E. Both A and C
This was due to: (one or more answers may be correct)
A. Design flaws by Airbus, which may cause confusion and/or ambiguities with respect to thrust lever handling upon touchdown
B. Inadequate training by TAM, which resulted in substandard technical knowlegde of aircaft systems and/or incorrect flight techniques
C. Very good training by TAM but despite this, usage of incorrect flight techniques
D. Both A and B
E. Both A and C
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EMIT,
My statistical conclusions were that there weren't any.
I hope I was clear on that.
You find that a "disturbing rate". I don't know. I find that because of their similarities these accidents are worth considering together in detail. But of course each accident individually is worth considering in detail, so that is not saying much.
Consider also that in all these cases the pilots did not follow SOPs, and that at least one of the SOPs they did not follow was a memory item. Indeed one could consider the MMI. And one must consider the "Pilot-SOP interface" also.
And training and recurrency checks. As well as how the crew managed their task distribution. These phenomena are all potentially involved.
And let's not forget that the reason we have 1,500 messages on this thread in 3+ weeks is primarily that the EMAS at the end of 35L was vertical! Because if there is one thing certain in the world of aviation mishaps, it is that someone is going to run off the end of a runway again sometime.
PBL
however I disagree strongly on some of your statistic conclusions.
I hope I was clear on that.
[Under the assumption of 1 landing with TR INOP in every thousand landings] there has been 1 accident per 17.000 flights with T/R de-activated, arithmatically speaking.
Moreover, ....... they all happened as a result of mishandling the thrust lever of the engine with the thrust lever de-activated. All with Autothrust active untill the flare. A serious issue from Man Machine interface standpoint
And training and recurrency checks. As well as how the crew managed their task distribution. These phenomena are all potentially involved.
And let's not forget that the reason we have 1,500 messages on this thread in 3+ weeks is primarily that the EMAS at the end of 35L was vertical! Because if there is one thing certain in the world of aviation mishaps, it is that someone is going to run off the end of a runway again sometime.
PBL