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TAM A320 crash at Congonhas, Brazil

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TAM A320 crash at Congonhas, Brazil

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Old 2nd Aug 2007, 19:02
  #941 (permalink)  
 
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@Rananim

Fully agree.
Spoilers were in the hands of the computers and could not be overridden.
Just say for example a TL was physically jammed by a foreign object. You would still want Spoilers. Sure shutting down the engine may give you auto spoiler but you would have gone an awful long way down the runway without spoilers. A luxury not afforded in this instance.

Would be interested to see if the Speedbrake lever was pulled. If it was not then would not have made any difference even if it did deploy the spoilers.

Jim
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Old 2nd Aug 2007, 19:11
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Can anyone explain the logic of designing an aircraft with software that allows one engine to be in full reverse and the other in TOGA power at the same time? Is there a concievable scenario where one would need this condition?
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Old 2nd Aug 2007, 19:12
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Rananim - well said!

Dreamland said: "then after selecting REV on the L/H engine, R/H engine accelerates to climb power. This has everything to do with the PILOT, not the computer."

Please help me understand how an engine "accelerating [of its own accord] to climb power" has everything to do with the pilot
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Old 2nd Aug 2007, 19:20
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Wileydog3,in his infinite wisdom,speaks of each design(AB and conventional)having their strengths and weaknesses and that the aviator must understand them and act accordingly.Thats quite frankly bs.
BS. Explain.

The pilot is your last and best chance and he must have full and total control of his aircraft at all times.Unhampered by mode confusion
You seem to be asserting that the pilot is infallible and that mode confusion is a phenomena specific to one manufacturer. Please explain how VNAV works in the various Boeings, Fokkers, etc and the defaults, especially with multiple crossing fixes and specifically with reference to being in a pitch mode or speed mode.

No tactile feedback and an over-reliance on the optical channel complete the sorry picture.
No tactile feedback? Hmmm. so let's do away with *artificial* flight feel so we can REALLY feel what the airplane is doing, not some old computer. And maybe back to open cockpits so we can hear the wind in the wires.

At the critical time(just after touchdown),control of the aircraft was in the hands of the computer,not the pilot.
You do realize that many aircraft won't give you braking if you don't get wheel spin-up or if a squat switch doesn't tell the systems the airplane is on the ground. Do we do away with squat switches also and anti-skid systems?
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Old 2nd Aug 2007, 19:29
  #945 (permalink)  
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Somethings are clear

1. Heavy plane (62.7 ton).
2. Extra Fuel (3-4 ton)
3. Right reverse locked out (the pilots knew this)
4. Short runway (1940 m)
5. No escape zone
6. Wet runway (slippery the day before and the day of accident)
7. No grooving
8. Right engine pulling forward
9. Left engine in reverse
10. Ground spoilers did not work
11. Brakes did not work
12. Pilot was not capable of reducing acceleration (lever did not move)

The president of TAM today at the House Representatives Committee, when reading the recommendations of ANAC skipped the part that said that in short and slippery runway both reversers should be used.

The House Representative Committee revealed yesterday all the conversation on the voice recorder and it was shown in TV.

The big question now seems to be pilot´s error or machine malfunction. A pilot who worked with the co-pilot at Transbrasil for 20 years, made a statement that he is sure that the co-pilot would not commit such an elementary error. He claim that neither him or the pilot, both very experiencec pilots. The controversy continues.
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Old 2nd Aug 2007, 19:36
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As I understand the logic in post #585, when the reverse thruster on engine 2 is inoperable, the thrust lever for engine 2 has to be 'at or near idle' when the pilot selects reverse thrust on engine 1 for the computer to command deployment of the ground spoilers.

I am puzzled by the lack of attention to the position of the 'other' thrust lever when it comes to actuating reverse thrust. If I have understood the logic correctly, reverse thrust can be actuated on engine 1 even if the thrust lever for engine 2 is not 'at or near idle'.

What situation might the programmers have had in mind where it is a valid combination to have engine 1 in reverse thrust and engine 2 in forward thrust?
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Old 2nd Aug 2007, 19:45
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I am puzzled by the lack of attention to the position of the 'other' thrust lever when it comes to actuating reverse thrust. If I have understood the logic correctly, reverse thrust can be actuated on engine 1 even if the thrust lever for engine 2 is not 'at or near idle'.
What situation might the programmers have had in mind where it is a valid combination to have engine 1 in reverse thrust and engine 2 in forward thrust?
Maybe not "in forward thrust", but if AB had designed the engines such that with a jammed single TL you were denied the ability to shut down the uncontrollable engine and then have REV available on the "good" engine, people would be crying foul about the designers denying the pilots control over their good engine. (The logic looks at TL position, not engine thrust, note)

Once you start generating scenarios with various primary flight controls (like TLs) jammed or faulty, its VERY difficult for a design to be bulletproof.

PS I don't believe that a jammed TL is currently part of the scenario for this incident, pending some definitive info (and a leaked CVR doesn't count as definitive in my book)
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Old 2nd Aug 2007, 19:55
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The big question now seems to be pilot´s error or machine malfunction.
This question is irrelevant since all it does is seek to blame

The contributing causes to the accident maybe a combination of these factors, and/or various others. That is, of course, up to the enquiry to establish. The purpose of the enquiry is not to pin blame, but learn from the factors, and their interraction, and make recommendations to prevent recurrence / enhance Flight Safety.

Speech over
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Old 2nd Aug 2007, 19:59
  #949 (permalink)  
 
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learsimmer
I am puzzled by the lack of attention to the position of the 'other' thrust lever when it comes to actuating reverse thrust. If I have understood the logic correctly, reverse thrust can be actuated on engine 1 even if the thrust lever for engine 2 is not 'at or near idle'.
Like all airliners, each engine is controlled by its' own thrust lever. What is puzzling about that?
What situation might the programmers have had in mind where it is a valid combination to have engine 1 in reverse thrust and engine 2 in forward thrust?
Engine 2 reverser inop? Then it is a valid combination.
TP

Last edited by TyroPicard; 2nd Aug 2007 at 20:07. Reason: Avoidance of apostrophe police.
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Old 2nd Aug 2007, 20:10
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Yes!!! And let´s do away with FMS because it may have played a role when someone entered a wrong fix that made a B757 slam into a mountain in Colombia(also due to a design flaw in which the speed brakes wouldn´t retract automatically upon goaround thrust selection)....
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Old 2nd Aug 2007, 20:23
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I may have missed something in the earlier posts, but there are a number of issues here.
1) There may be slight logic differences between the CFM engine and the V2500 engine as fitted.
2) Unless both thrust levers are at least at idle then autospoilers, autobrakes and reverse on the selected engine are not available.
3) The spoilers would retract if TOGA power were selected for a go around.
4) If one thrust lever were left in the climb detent and the other retarded to idle or reverse on the call of RETARD would the autothrust disarm or would the aircraft remain in speed mode and maintain Vref. I think probably the later!
5) On a recent training detail (Sim) a FADEC fault resulted in an engine shutdown. As the command (ECAM) to bring the thrust lever to idle is generated by the FADEC( which had failed) the thrust lever remained in the climb detent. When the crew landed they became distracted because they only achieved REV in amber on the live engine and could not get the engine to spool up. More relevant however was the fact that the spoilers had not deployed and the autobrakes had not engaged. This was a situation the crew had not seen before and was confusing. Imagine that on a short wet runway.
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Old 2nd Aug 2007, 20:30
  #952 (permalink)  
 
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Post Interview for Brazil newspaper

Dear colleagues,

I am a journalist from Correio Braziliense, which is the most important daily newspaper in Brazil´s capital. I am producing a special article about transcript of voice recording from Airbus A-320. I would like to interview professional pilots with experience in this airplane. Please contact me urgently by [email protected]

Regards

Rodrigo Craveiro
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Old 2nd Aug 2007, 20:44
  #953 (permalink)  
 
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Can anyone explain the logic of designing an aircraft with software that allows one engine to be in full reverse and the other in TOGA power at the same time? Is there a concievable scenario where one would need this condition?
I believe this is the key question. There is no logic which would support such a condition. AB should just fix it. They are going to get sued anyway, everybody does when something like this this happens. So just fix it.

But I think another several other posts that spoke of a "culture" developing around each manufacturer is spot on. It appears in the case of AB, the culture includes a belief that the software will not allow the aircraft to fly outside the envelope, which is probably true if you understand each and every mode, AND you understand the effects changing things within a mode will have on the overall logic. The problem is that this creates a chess game in your head, and when you have a severe time contraint thrown in for good measure, you are suddenly in multi-tasking overload. You also can't believe that the "culture" would let you down, and you continue to try to depend on it even as you run out of runway. The "logic" of the software logic letting you down just does not compute.
How many of us spend time wondering what the hell our computer is doing at times? (especially in a Windows environment ). When you allow for so many possible combinations, you will automaticaly introduce confusion. One merely has to look at the nearly 1000 posts in this thread to see the amount of confusion involved here. And I know that some of you get it and understand it, but obviously many do not. And I am not talking about the posts from non pilots. Even the posts from A320 pilots have been contradictory. This type of confusion is so common in computer based technology. But in a critical phase of the flight, complete understanding is a must.
No, I am not a pilot. But with over 30 years in the IT industry, I do know end user interfaces. Throughout all of technology, the biggest challenge for us has been how to offer more capability without confusing the end user. Just look at your television remote, or your cell phone. How many of us understand EVERY function? The bottom line is, the more complicated you make the logic, the more difficult you make it for the average user to understand all of the implicaitons of their actions, which will add additional time into the decision making process. And when you have 19 seconds to figure it out, the odds are not good.
So back to the quote I placed at the top. I am sure no pilot would believe that an aircraft software system would attempt to place one engine in TOGA mode while he was attempting to land and reversing the other engine. The thought would never enter his head. The logic fails, the culture prevents one from accepting that fact, and the results are self evident.
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Old 2nd Aug 2007, 20:45
  #954 (permalink)  
 
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latest from Flight Intl...

...with more inside news...expect telexes, ADs...

TAM A320 crew did not retard right-hand thrust lever

By David Kaminski-Morrow

Information on the TAM Airbus A320 accident shortly to be made available to
operators will show that the crew retarded only the thrust lever for the
left-hand engine during touchdown, leaving the other in its forward position.
Industry sources say the information, to be set out in a communique, shows
that the crew made a normal approach to Sao Paulo Congonhas Airport on 17 July with auto-thrust selected – the aircraft operating under a ‘managed thrust’ regime – and the thrust levers in the ‘climb’ position.

For reasons yet to be explained, the pilot, in the final moments before
touchdown, retarded only the thrust lever for the left-hand engine – first
into the ‘idle’ position, then into ‘reverse’. This action disconnected the
auto-thrust, as per its design. The failure to move the right-hand engine’s
thrust lever to the reverse position runs contrary to the standard operating
procedure which calls for both levers to be set to ‘idle’ and then 'reverse' –
even with a thruster reverser inoperative.

It is unclear why the right-hand engine thrust lever was left in position.
Newly-released cockpit-voice transcripts have notably highlighted the crew’s
awareness that only the left-hand engine had an operable thrust-reverser; the right-hand reverser had been deactivated. This, however, should not have made a difference to the thrust retardation procedure.

As the aircraft began to slow after touchdown the thrust being produced by the right-hand engine remained at the level it was at when the auto-thrust had disconnected. With the thrust lever forward the spoilers would not have
deployed, and the auto-brake would have similarly been inhibited.

In the cockpit transcript the co-pilot appears to state that the A320’s
spoilers did not activate on touchdown and, as the situation develops, the
pilots are heard to say that they cannot slow the aircraft. Flight-data
recorder information indicates that the pilots repeatedly pressed on the
brakes in a bid to stop the jet but did not retard the right-hand thrust
lever.
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Old 2nd Aug 2007, 20:58
  #955 (permalink)  
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More...

They also tried to deccelerate by pulling the right lever back but the one who tried said: " I can´t do it , I can´t do it, I can´t do it " .
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Old 2nd Aug 2007, 21:05
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Can anyone explain the logic of designing an aircraft with software that allows one engine to be in full reverse and the other in TOGA power at the same time? Is there a concievable scenario where one would need this condition?
I believe this is the key question.
So let's ask the Boeing pilots the key question - is there anything on your aircraft that will prevent reverse on one engine and forward thrust on another ? Please answer because a lot of uninformed people seem to think it should be impossible.
Thanks, TP
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Old 2nd Aug 2007, 21:18
  #957 (permalink)  
 
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Please help me understand how an engine "accelerating [of its own accord] to climb power" has everything to do with the pilot
Eeerrm...there is just a slightest of the possibilites that said engine was trying to match thrust demand given by the thrust lever and the guy (or gal) who operates the thrust levers is called... errr... uh... pilot?

Autothrust always disarms after touchdown.

Memory items for no spoilers after ldg (per my instructors, no written reference available)

- lift reverse levers
- if they move PNF calls out: "****, we forgot to arm the spoilers" and then the spoilers deploy
- if they don't move, slam the TLs into idle and then the spoilers deploy
- if you're alredy in reverse and there are no spoilers PNF calls out: "****, no spoilers, we're ****** dude!" and prepares for overrun.

Of course, those are just-in-case-items, we never needed to use them since we got our first bus 10yr ago.
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Old 2nd Aug 2007, 21:18
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Originally Posted by dreamland
At the critical time(just after touchdown),control of the aircraft was in the hands of the computer,not the pilot.
I think you are confused, it APPEARS that the thrust lever on the R/H engine was never retarded in the flare (what airplane if any can be landed properly without reducing thrust at landing?), it had to make the aircraft float somewhat, then after selecting REV on the L/H engine, R/H engine accelerates to climb power. This has everything to do with the PILOT, not the computer.
(all still theory, not discounting some type of sensor failure until more facts are presented).
yes, but IF the thrust lever wasn't retarded - which sets of the chain of events by not deploying the spoilers, it can still be attributed to airbus's bizare non-moving thrust levers. You are quite right - no airplane can be landed correctly without retarding the thrust, but thats the point, in any other aircraft you would be floating along a runway thinking "why isn't it touching down, oh bugger I've still got some thrust on, Go around", embarassing, stupid maybe, but not fatal.
The concept of detents for Climb, TOGA power etc is inspired, much more sensible than separate thrust levers and a dinky little mode panel, but the concept of not moving the thrust levers between climb and idle is incomprehensible - what exact benefit did the airbus engineers think they were giving with that particular 'feature'? Every aircraft, ever built has the engine thrust proportional to some form of moving lever in the cockpit - it works, has done for 100 years. If it ain't broke don't fix it springs to mind.
Mabe the pilot did forget to retard the lever (can't see why myself), but the design and concept of the machine allowed him to do this, and that in my book is a problem. call it what you will, a latent error, a human factor issue, but its still a problem.
this is going to run and run, and I can see airbus needing to answer some particularly stiff questions in a court of law. The most relevent one being "why did you do it that way". Whatever one thinks of the other envelope protections on the Airbus, one can also construct a compelling argument to justify their inclusion - sure they can lead to mode confusion (so does VNAV on my beast), but they also provide a significant benefit.
I honestly can't see a single benefit from non-moving TL's, and can see a whole lot of problems, at least one of which is tragically now visible to the whole world.
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Old 2nd Aug 2007, 21:24
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I noticed on the video submitted yesterday that the pilot showing a normal A320 landing after going to idle immediately pulled both reversers to full and his hand and fingers were above the throttles or at least to the top with the reverser controls.

If the TAM crew used the older method of only pulling one reverser into reverse if one was inop I can see only having the little finger to prevent advancement of the other throttle if the throttle physically advances. If they used the older method of one reverse to prevent that small increase in #2 engine they may have inadvertently, to prevent #2 from going into reverse, not gotten it all the way back to idle. His comments that #2 was stuck and he couldn't move it back must play a big part in this accident.

I have never flown an airplane where you could go from idle to full reverse position without waiting for logic to confirm reversers were positioned properly, then increase reverse power symetrically. From what I have read here the A320 reverser levers will go to full reverse position even if they are inop.
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Old 2nd Aug 2007, 21:26
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So let's ask the Boeing pilots the key question - is there anything on your aircraft that will prevent reverse on one engine and forward thrust on another ? Please answer because a lot of uninformed people seem to think it should be impossible.
Thanks, TP
nope, pretty sure I could do that if i wanted to
but as i said above, in reality I couldn't because I wouldn't actually land if I left a lever forward. I would float way down the runway.
In auto land the levers retard themselves, In manual landing I obviously control them myself. In no case could i actually touchdown in the zone, on speed with a thrust lever forward.
AIUI the airbus will retard thrust automatically regardless of lever position, land, and then disconnect the AT and spool the engine back up to the TL position if the TL is still forward.
On my 757 the thrust is NEVER anything other than the TL position.
Of course having landed I could put one in idle and shove the other lever forward 'spose- dunno - never tried it! but thats what I would have to do in order to achieve what happened here - considerably different and a deliberate action i think you'll agree.
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