TAM A320 crash at Congonhas, Brazil

[bsieker]

Originally Posted by PJ2

Also, there may be different sample rates, varying from once per second to eight times per second.

The Taipei Sungshan incident report states in the appendix (p146, response from Airbus) that the brake pressure is only sampled once every 4 seconds.

I'm not sure about the recorder type of this particular aircraft, but this seems a low rate, considering that anti-skid will modulate brake pressure much faster than can be recorded.

(Although Concorde was a much older aircraft, I remember from my analysis of the Concorde accident, that its FDR sampled each engine's parameters only once every 4 seconds in a round-robin fashion, which made exact engine behaviour (e. g. surging) hard to detect)

Originally Posted by Dream Land

wasn't it about 30 seconds after touchdown when the NFP announced "no spoilers" or something similar?

Looking at that transcript again, let's assume MLG touchdown is two seconds after "twenty" call (some A320 pilot said the touchdown noise in the cockpit is NG touchdown), then we have:

18:48:21 "twenty"
18:48:23 MLG touchdown
[...]
18:48:26.3 NG touchdown
[...]
18:48:29.6 HOT-2 "Spoilers Nothing"

That's 6.6 seconds after (assumed) MLG touchdown, or 3.3 seconds after NG touchdown, either way a long shot from 30 seconds.
A normal landing would have something like (give or take):

0s FWC: "twenty"
2s MLG touchdown
6s PM: "ground spoilers"
9s PM: "reverse, decel"

(These callouts can be heard near the end of this video, start around 4:40.)

[GearDown&Locked]

I was wondering about those “turn, turn, turn” words from the crew. This remembered me of a previous incident at Naples last April, when an Aliatalia A321 experienced some sort of brake failure and that crew made a 180º turn to stop the aircraft. http://www.pprune.org/forums/showthread.php?t=271529

If the crew sensed they were facing an imminent catastrophe why didn’t they throw everything out, using brute force like the parking brake? Doesn't come to mind in this type trainning?

[bsieker]

Parking Brake

Originally Posted by GearDown&Locked

If the crew sensed they were facing an imminent catastrophe why didn’t they throw everything out, using brute force like the parking brake? Doesn't come to mind in this type trainning?

Use of the Parking brake is the last-ditch effort, if all other brake systems fail. It is part of the "Loss of Braking" memory item:

[... failure of autobrake, manual normal brake, manual alternate brake ...]
IF STILL NO BRAKING
- PARKING BRAKE ............ USE
Use short successive parking brake applications to stop the aircraft. [...]

But you don't do that unless all other braking systems have failed. There is no indication that normal mode manual braking (with anti-skid) did not work.

The parking brake is not designed to decelerate the aircraft, it has no anti-skid, it cannot be modulated, it has a fixed brake pressure, and it may brake asymmetrically, causing a yawing moment.

Most importantly, it will provide less deceleration than the normal or alternate brakes.

[Our-man-in-CGH]

Info that may or not be confirmed but I read:
a) the two pilots flew from Congonhas to Porto Alegre on the same day before coming back to Congonhas. Correct.
b) both had more than 14000 hours of flying. Incorrect for one, but not by much, both had more than 13000.
c) one of them flew many years (20) for Transbrasil on 767. In 2001 worked from September to December at GOL (Boeing 737). In January
2007 started at TAM and up to recently was in training for the A-320
plane. The other was with TAM since 1987. I cannot verify all of these statements, but one had flown 767s with TransBrasil.
d) TAM did not incorporate the modifications that AB suggested after the Taiwan accident. For some reazon this was not mandatory by AB. Why? No comment

And...a question:

Why one of the pilots said that he couldn´t do it after the other asked him to decrease acceleration? No comment

As for the wheel brake debate, remember my previous post in relation to the wheel brakes where it was stated that 3 out of 4 were applied when recovered from the accident site and there was damage to the leg with the fourth one on it?

Airbus state full wheel brakes applied. Therefore, look at the deceleration components of brake efficiency, friction coefficient, weight on wheels, 1% downhill slope, thrust, aerodynamic drag etc.

[discountinvestigator]

Have I missed the debate about putting in full forward stick in the event of spoiler failure in order to reduce the wing AoA to the maximum extent possible through nose gear compression. Not sure if it would help much but it might give you the odd degree less of AoA and thereby decrease the lift generated by the wing.

Our Man: what is nosewheel steering directional control like on the centreline of 35L?

[Our-man-in-CGH]

Our Man: what is nosewheel steering directional control like on the centreline of 35L?

On the paint markings in the wet, not good. Water does not run off the middle paint markings because there is no slope at that point. Not sure if the aiming point blocks would trigger anti-skid in some wet conditions.

Friction report published by the airport operator for tests on the new runway surface do not mention the paint markings as being tested, only the surface.

[James7]

Discount.....

I think it is better to pull the stick back and thereby increasing the downforce on the main wheels.

Nosewheel down, stick back.

Survivor Ability
This point has been mentioned in passing a few times and will be a question for the coroner to answer.

'Why did such a simple error lead to the deaths of so many'. I think there will be a few searching questions to the airport operator.

Jim

[discountinvestigator]

For the failure of ground spoiler case only:

Once the nose wheel has been put on the ground, if you pull back on the stick, you are generating downforce on the tail and therefore, a rotation around the main wheels, where possible. This is likely to unload the nosewheel oleo and either lift the nosewheel back into the air, or at least attempt to increase the angle of attack of the wings. This will keep the lift generation of the wings going and thus reduce the effective weight on mainwheels. Braking deceleration is a function of weight on mainwheels.

Was the Airbus design logic to build in ground spoilers and deploy them on landing to minimise the ground roll for contaminated runway operation, or was it to reduce any lift generated with the nosewheel on the ground in normal operations (or both). I have no knowledge of the effective wing AoA on the ground.

[James7]

Discount

Sorry discount have to disagree with you on this point. The important action is to get the weight on the wheels. Spoilers will kill the lift thereby producing a downward force on the wheels. Holding the stick full back will increase the downward force on the mainwheels and this is what is desirable. With the aircraft on the ground and engines at or near idle, extra lift will not be generated. Braking action no matter how small should stop the nosewheel from lifting.

I do agree though that the nosewheel should remain on the ground.

Jim

[bomarc]

in little planes, pulling back on stick after landing is a good idea.

however, in big planes, pushing forward a bit to keep the nosewheel in contact with the ground might aid directional control.

certainly not to the extent to cause wheelbarrowing.

( still remember my first checkride, the FAA check airman asked this question and then went on to say...that's right, back stick on a small plane...NOW IF YOU WERE LANDING A B24 it would be different!) :-)

it is a shame that with all the super duper stuff on the airbus, that a gadget wouldn't make a sound indicating SPOILERS DEPLOYED. As mentioned before, in some older jets, the mechanism itself is so noisy that a pilot detects spoiler deployment by non visual means.

this would allow the pilot flying to keep his eye on the runway and know the spoilers deployed...confirmed by NFP.

Oh for the days of the flight engineer! I'll bet he would have pulled the throttles back or shutoff the engines.

[marciovp]

Translation

But "desacelerar" means "to decrease acceleration"... while "to brake" seria "freiar". "is there such a word as "descelerate". I have some doubts if someone wanted tell the other "to brake" he would say "desacelerar". Oops. how these translations are important.
Yes, there is a touching article about a colleague who worked with the pilot from Transbrasil for twenty years flying with him to US, where he mentions how healthy and competent he was. He was the co-pilot on the day of the accident and after six weeks training with TAM he had been promoted to "Comandante". He was quite happy. He lived in Sao Paulo.

[bomarc]

if we had a new captain, just trained and typed on the 'bus and a checkairman, perhaps one of the most capable on the plane (assuming merit) we have a real problem.

a teacher/evaluator and a new student.

both should be very full of procedures and understanding, and both with experience on other planes.

both with respect for the airport and its conditions.

something ain't right...you all do the math.

[SoaringTheSkies]

Well, Bomarc, how about the not-so-rare situation of ranking conflicts?
I have no idea how those two related to each other, obviously one new with the company and on type while the other was very experienced in both.
Who was PF? I assume given the training situation it was the more "junior" pilot?
If it was the other way round, the seniority issue might have played a role.

pj

[bomarc]

while conflict in the cockpit has caused problems in other situations, consider:

a friend of the new pilot with TAM said he was very happy there...I assure you if I had a conflict with a training pilot of any sort I would have told my friends about it...and they would be speaking up posto facto.

both of these pilots were past what I consider the magic number of 8760 hours...you can all try to figure out the importance or significance of that number. but if you have that much time or more (as both men had) your ability to put up with crap is much diminished, and certainly not to the point of your own death.

I recall a western airlines DC10 landing in mexico and the copilot didn't tell the captain that the runway was closed...sure, stuff happens...but not here I think.

[bubbers44]

I can see a sensing fault or a pilot somehow forgetting to retard #2 engine concentrating on reversing #1 but I can not comprehend not using manual brakes for 11 seconds after touchdown. Just count off 11 seconds to realize how long a time that is especially on a short runway.

[borghha]

If I've read the brasilian press correctly, it was the 'senior' TAM pilot who was PF.

I remember from the Air France A340 toronto accident, that the PNF couldn t get to the throttles to apply REV because the PF was holding them firmly while he was trying to keep the aircraft on the RW. (heavy wind) Could something similar have happende here, so that the PNF (junior pilot) couldn't see that the other TL was not at idle?

[James7]

Briefings

It was already mentioned earlier on - how interesting it would be to hear the approach briefiing on the CVR.

Also it would be interesting to hear the 'Take Off Emergency Brief' if there was one. I always say something to the effect 'that in the event of stopping the aircraft I will retard all 4 engines and pull all engines into reverse' and will follow this up with simulated hand movements. My brain, tiny as it might be, will hopefully remember what to do when the sh!t hits the fan and hopefully will not forget to pull all the reversers or close the thrust levers. The interlock system will take care of things on a 4 engine jet if it has to.

The point being, did the PF say he will reverse both engines or just the No1.

Bubbers - The TW incident it took 18 secs for the pilot to apply the brakes. 11 secs is a long time on a short runway especially as manual braking was the normal procedure.

Post #1236 Airbus Telex states that the CM1 was the PF. The CM1 is the pilot in the Left seat.

Jim

[SoaringTheSkies]

Bomarc,

when I said ranking issues, I didn't mean real grief between the two. I meant that, if the senior pilot was PF, the junior would have had to overcome a hurdle to tell his checker that he thinks his procedure was wrong. I assume that this situation would have been trained in the sim before (one reverser inop, maybe even into a short, wet strip) but still there's a chance that the new guy will give the more senior one credit to do things that are "different".
In short: maybe the PNF assumed that the PF knew what he was doing due to his vast amount of experience on type.

pj

[bubbers44]

Remember the "good old days" when a microswitch or system logic fault or pilot not quite handling the throttles correctly would still let you land uneventfully? I guess those days are coming to an end.


Unfortunately I am talking about the 757 era aircraft.

[ELAC]

bubbers44,

After your post your post #1227:

... Boeing systems don't put you in that predicament. Boeing systems are so much more pilot user friendly than Airbus. You always get what you ask for. You don't have to see if Airbus logic agrees. When have you seen a Boeing aircraft go off the end of a runway over 100 knots because the pilots could not control the thrust? No matter who is at fault.

In response I asked:

BTW, I'm just curious about how many hours of operating experience on Airbus A320/A330/A340 aircraft lie behind your assertion that "Boeing systems are so much more pilot user friendly than Airbus." I'd assume you have at least a thousand hours or more on both manufacturer's models before you'd be so bold as to venture that sort of an opinion?

So far you have yet to reply to that question either publicly or privately.

But now you come up with:

Remember the "good old days" when a microswitch or system logic fault or pilot not quite handling the throttles correctly would still let you land uneventfully? I guess those days are coming to an end.

Unfortunately I am talking about the 757 era aircraft.

So, I am forced to ask again: What qualification do you have to that entitles you to make this comparison or judgement? Exactly how many hours do you have on Airbus FBW aircraft and what do you know about their systems? My suspicion is that the answer amounts to what we in Canada call a Donut Hole, but please feel free to prove me wrong.

If your opinions are the result of actual experience operating aircraft of both designs you are fully entitled to them, however much I may choose to disagree with you. But, if you have no serious operating experience with the Airbus types, or detailed education regarding how their systems work, I'd suggest that your opinion is no more than the uninformed viewpoint of someone who has yet to take the opportunity to become acquainted with the facts. That might be enough to earn you a pass on the spotters balcony but this thread is a serious discussion about serious issues and an unsubstantiated opinion about the "good old days" (on a B757 of all aircraft, for heaven's sake!) when "a microswitch or system logic fault or pilot not quite handling the throttles correctly would still let you land uneventfully" just isn't going to cut it.

So, I ask again: What is the experience and what are the qualifications that you rely on to support your opinions? Unless you're prepared to answer that we really don't whether your opinions are informed or otherwise. And I'm sure you know what they say uninformed opinions are like?

On this element of the discussion I'd suggest that it's put up or shut up time. Either divulge the underlying experience that forms the basis for your point of view or as an alternative consider restricting your printed observations to those that you have the background experience to support.

ELAC

(and to head of the inevitable: 3 Boeing type ratings including multiple thousands of hours very happily spent flying the B757)