TAM A320 crash at Congonhas, Brazil

[Rob21]

PBL,

The pilot did apply manual brakes five seconds after the "no spoilers" call.

Why do it (apply manual brakes) before the call?

IMO, the delay to apply manual brakes was not 10 or 11 seconds, as stated for almost 2160 posts by "experts".

[PBL]

Originally Posted by Rob21

The pilot did apply manual brakes five seconds after the "no spoilers" call.

The first recorded significant application of both brakes is at
18:48:35, ten seconds after recorded WoW on both mains.
Maximum braking is recorded at 18:48:36

Originally Posted by Rob21

Why do it (apply manual brakes) before the call?

Because you want to stop as fast as possible, rather than waiting a number of seconds for the autobrakes to kick in.

Originally Posted by Rob21

IMO, the delay to apply manual brakes was not 10 or 11 seconds, as stated for almost 2160 posts by "experts".

I doubt you have read the posts in this thread discussing this issue. And if you don't think those discussants were experts, exactly who do you think is an expert?

PBL

[Rob21]

PBL,
Maybe I got it wrong, but until the "spoiler nada" call, the landing was "normal".
So why apply manual brakes (@ 140 kts) before that call? With no spoilers you won't have effective braking anyway... I agree with you that pilots want to stop as soon as possible, but brakes alone do almost nothing @ 140 kts with no spoilers. Am I wrong?
You shouldn't "feel" some decel (from reverse thrust) before applying manual brakes?
Note that the TAM's pilots cycled the spoiler armed switch almost at the same time they went to manual brakes.
And last, the nose wheel shouldn't be on the ground before applying manual brakes?

[Lemurian]

Landing : abort or not . Piloting issues.

The FCOM and some manufacturers publications give some guidance to the landing and go-around techniques. The following are general rules, applicable to all types of aircraft.

1. A stabilised approach, in configuration, speed and flight path.
2. A firm touch-down as close as possible to the touch-down zone.
3. A prompt selection of thrust reversers.
4. A monitoring of the availability of speedbrakes
5. A timely and modulated brake application ensuring a controlled speed before runway exit.

The main problem lies with the built-in priorities in the deceleration devices : The speedbrakes' failure to extend means the unavailability of automatic wheel brakes which should trigger a pilot takeover on *manual* use of the brake pedals and the deployment of a thrust reverser discourages an attempt for a go-around and we find ourselves in a *cul-de-sac* where the apparent only option is to stick to the landing and try to stop before the end of the runway.

1. CONTINUE THE LANDING
   The procedure requires a good crew's grasp of the aircraft systems and SOPs, in terms of adherence to general call-outs and systems abnormality management, the *triggers* for emergency memory items...etc... In this instance, the addition of a *No Deceleration* to the correct *No Spoilers* announcement by the co-pilot could have speeded-up the pedal brake application. The study of the dynamics of the accident show that the exit speed would have been vastly reduced. IMHO, a change in the SOPs is required.
2. ABORT the LANDING
   I am here on a very shaky ground as both manufacturers expressly discourage an attempt to go-around after reverser election.
   The reasons are :
   1/-The risk of an engine compressor stall
   2/-The risk of the reverser not stowing properly in its locked position
   3/-The risk of major thust assymetry as both will accelerate at different speeds
   4/-The risk of not meeting the required climb gradient with a late rotation on the runway compounded with an important flaps drag.
   Thinking in general terms, any attempt to touch-and-go has to cater for all the above points but in reality, everything boils down to *Get the engine{s} out of reverse and allow it (them) to stabilise in forward thrust with the reversers stowed* before a go-around thrust application.
   That delay will also be used for retracting the flaps to a lesser setting (which is a normal requirement for an overshoot anyway).

Looking now at the different times required :
- 3 seconds to cancel reverse thrust
- 2 seconds for stabilisation into forward idle
- 5 seconds for acceleration to CLB thrust, during which directional problems will be the most important as the engine left in CL will reach GA sooner.
- 3 seconds to reach GA thrust.
Total time : 13 seconds. Considering the landing speed of the CGH A320 - 140 kt or 72 m/s - it represents a ground roll of some 936 meters beyond the touch-down zone.. Of course, we have to consider that the aircraft might have achieved airborne speed before the end of these long 13 seconds as the deceleration was basically nil.
Any attempt to rush that procedure means impending catastrophe and, as far as I know, only TRIs who have practised touch-and-goes during initial base training seem capable of pulling it off successfully.
Should our training be changed to include *rejected Landing*?
A few articles for your perusal :
AI rejected landing
BAC wet runway guide

[bsieker]

Originally Posted by Rob21

And last, the nose wheel shouldn't be on the ground before applying manual brakes?

Should be for comfort, but does not have to be.

Originally Posted by FCOM 3.03.22, P5

[...]
. Braking may be commenced before nosewheel is down, if required for performance reasons; but when comfort is the priority, it should be delayed until the nosewheel has touched down.
[...]

Bernd

[flyingnewbie10]

Your french is pretty good. just add a *z* to "arrete" to get the polite form of verb address and it would be perfect.

Fixed.

Let me help you to keep as objective and exact as possible. Going back to the discussion about manual brake application:

1 - The information in the Article was really wrong when it stated that brakes were applied 5 seconds after touchdown. Something I think that is not controversial.

2 - Rob21 asks why manual brake should be applied before the spoiler (state) call. I think the question wasn't objectivelly answered as yet.
And I aggre with him though I am not an expert. At 140knts (almost 260 km/h) why would one apply manual brake at touchdown in a (supposedly) slippery runway to face the risk of stopping in the depths of Jabaquara (a district nearby) ?

[RatherBeFlying]

the deployment of a thrust reverser discourages an attempt for a go-around and we find ourselves in a *cul-de-sac* where the apparent only option is to stick to the landing and try to stop before the end of the runway

This doctrine came about as a result of the Cranbrook accident where a 737 cancelled reverse and attempted a go-around upon seeing a snowplow on the runway. Back in the air one of the engines fell back into reverse and the affected throttle snapped back to idle with such force that it broke the captain's thumb

Some hundreds of posts ago, I suggested waiting for spoiler confirmation before selecting reverse to preserve the option of a rejected landing since as we have seen, an announcement of "spoilers nada" on a critical runway after reverser deployment is not much more than an announcement that we will be going off the end.

Using Lemurian's 72m/s at 140 kt. and his 5 seconds to cancel reverse and stabilise in forward idle, we would be using 360 m less runway.
To that we would have to add a few seconds of waiting for spoilers, which may result in recalculation of landing distances on contaminated runways where spoiler usage is factored in.

[flyingnewbie10]

Anyway,

This accident will demand a lot of work from investigators.

A detailed knowledge of the A320 Thrust Control System, TLA reading, hardware/software interfaces, etc. I think that at the present status either a HF or electronical/mechanical problem have the same probability.

Maybe the CVR shows something but I am not too confident on that.

If the Thrust Levers at least had some independent sensors at the TL track this investigation might not be that difficult. A TL motion could be detected independently of a change in the TCU TLA reading.

[marciovp]

Sorry Lemurian...

Regarding marciovp's citations, and here I disagree with PBL, it is not a matter of contestation, it's the fact that obviously this accident has a lot of political implications which are polluting both the families' privacy and right to mourn their losses serenely and this thread which should remain as objective as possible

.

Of course I respect your views but I decided to allow myself the right to disagree in a proper way. You know that air disasters have many dimensions and this one is not different than the others. Even if indeed the "objective" cause was the TLs giving opposite commands because the pilots did not pull the right engine to Idle, still there are questions to be asked. Let me mention a few, some of them very "subjective" that, in my views, could be addressed:

1. Why the plane was loaded with more fuel than needed?
2. Why the plane was carrying more people than it was certified for? (It was certified for 162 seats and had 174 seats).
3. Why did this plane landed with a locked out reverser in a short, wet, slippery runaway?
4. Why didnīt AB make it mandatory for all A320s to have the new software that keep advising the pilots of one TL not being in Idle or Rev.
5. Why this particular plane has had now three similar accidents by six pilots making the same mistakes?
6. Why ANAC made a rule that planes should not land in Congonhas with one reverser locked out and then withdrew it?...
7. Why Congonhas runway was liberated in a rainy day without grooving?
And so on.

If our aim is to learn the better we can about the factors that may have made this disaster possible in order to prevent further ones, isnīt this a way to respect and protect many crews, passengers and families in the future?...

It seems to me that it is of interest to know not only what CENIPA is investigating but also about information coming from any agency that is investigating the disaster.

[PBL]

Originally Posted by Rob21

Maybe I got it wrong, but until the "spoiler nada" call, the landing was "normal".

The landing was anything but normal throughout. They had significant forward thrust on #2 engine during and after the flare.

Originally Posted by Rob21

With no spoilers you won't have effective braking anyway......... brakes alone do almost nothing @ 140 kts with no spoilers. Am I wrong?

Yes, you are very wrong.

For example, it appears that with one engine producing significant forward thrust on a wet "slippery" runway one can obtain braking without ground spoilers at the rate of over 1.2 m/s/s. Imagine what you could do on a dry runway with both engines at idle!

Originally Posted by Rob21

You shouldn't "feel" some decel (from reverse thrust) before applying manual brakes?

You can apply manual braking whenever you think it necessary, say at WoW both MLG.

Please, Rob21, go back and read the extensive discussion on this thread about the braking and the braking performance. I don't have the time to repeat it all over again, and I doubt that others will feel much differently.

PBL

[Rob21]

PBL,

Yes, maybe I'll go back and read again posts about this braking issue.

But as for now, I don't agree when you say that during flare engine #2 had significant forward thrust. It had the expected thrust. It was only when engine #1 had reverse engaged that EPRs "split" (by FDR). And this was after the flare and after touchdown. Untill then, yes, things were "normal".

So maybe I should refrase my question on when the pilot was expected to apply manual brakes. Autobrake was selected to med, as recommended for slippery runways. Autobraking starts with ground spoiler deployment.
Why not start manual braking also with spoiler deployment?

If you brake with no ground spoilers on a wet runway, the risk of aquaplaning isn't higher?
It makes more sense to me that only without lift on the wings you can think on stopping fast.

I now know that manual brakes can be applied before nosewheel touchdown. But this is a correct procedure on a wet runway?

Are you sure I am wrong assuming pilots wait for spoiler status call before applying manual brakes, when landing on a wet and slippery runway?

[bsieker]

Originally Posted by Rob21

Autobrake was selected to med, as recommended for slippery runways. Autobraking starts with ground spoiler deployment.
Why not start manual braking also with spoiler deployment?

Why should manual braking depend on ground spoilers? If you planned to depend on ground spoilers, use autobrake.

If you brake with no ground spoilers on a wet runway, the risk of aquaplaning isn't higher?

Higher compared to what?

The risk of aquaplaning isn't higher when braking than when not braking.

The risk of aquaplaning is higher without ground spoilers than with ground spoilers.

It makes more sense to me that only without lift on the wings you can think on stopping fast.

There is nothing gained by delaying braking. If and when ground spoilers deploy, all the better, you will get optimal braking conditions. But until then you can, as we have seen, brake with perhaps 1.2m/s/s, instead of nearly nothing if you don't brake. Every little bit helps.


Bernd

[flyingnewbie10]

For example, it appears that with one engine producing significant forward thrust on a wet "slippery" runway one can obtain braking without ground spoilers at the rate of over 1.2 m/s/s.

PBL,

Technical sources, please. With actual experiments preferably.
(Maybe one can get a much higher braking rate this way by just skidding out of the runway and hitting something around...)

[Soga]

To READ and Think , TAM accident report

The data which follow have been approved for release by the Brazilian
investigation authorities.
>
> It is confirmed that the aircraft was dispatched with the Engine 2 thrust
reverser inoperative as
> authorized by the MEL.
>
> It is confirmed that the associated operational procedure of TAM MEL was
updated according to
> current MMEL page 02-78 p1 SEQ 001 REV 29 which reminds the crew to select
both thrust
> levers to idle before touchdown and requires to select both reversers at
touchdown
>
> The following is the sequence of events according to the recorders:
>
> Final Approach phase:
> - The aircraft was approaching runway 35L.
> - The last wind information given to the crew by the ATC was
330°/8kts.
> - The runway condition given to the crew by the ATC was wet and
slippery.
> - Landing configuration was established with Slats/Flaps fully
extended, gear down, ground
> spoilers armed, autobrake selected to MED.
> - Approach speed was 145 kts
> - The final approach was performed with Autopilot OFF -
disconnected at about 370 feet
> (radio-altitude), Flight Directors ON, Auto-Thrust (ATHR) ON.
> - The CM1 was the Pilot Flying.
> - The crew approach briefing included a reminder that only the left
engine thrust reverser
> was available.
>
> Flare and touch-down:
> - During the flare, the "RETARD" call-out has been normally
triggered
> - The "RETARD" call-out has been triggered 3 times, ending at the
selection of the engine
> 1 reverser.
> - Before touchdown, the engine 1 throttle was retarded to idle.
> - The engine 2 throttle is recorded in the Climb position and
remained in this position to the
> end of recording.
> - Preliminary trajectory computation indicates that the aircraft
landed in the touch-down
> zone.
>
> Landing roll
> - Just after touch-down, idle reverse was selected on engine 1,
followed within 2 seconds
> by the selection of max reverse which was kept to the end of
recording.
> - Following reverser 1 selection, the ATHR disconnected as per
design and remained
> disconnected to the end of recording.
> - With the engine 2 throttle being in the Climb position: 1/ the
engine 2 EPR remained at a
> value of approximately 1.2 corresponding to the EPR at the time of
ATHR disconnection;
> and 2/ the ground spoilers did not deploy and the autobrake was
not activated.
> - Maximum manual braking actions began 11 seconds after touch-down.
> - Rudder inputs and differential braking have been applied during
the landing roll.
> - The aircraft overran the runway at approximately 100 kts.
>
> DFDR and CVR data show no evidence of aircraft malfunction.
>
> At this stage of the investigation, and as already indicated in the
previous AIT n°3, Airbus remind
> all operators to strictly comply with the following procedures:
>
> A- During the flare at thrust reduction select ALL thrust levers to IDLE.
>
> B- For the use of the thrust reversers when landing with one Engine
Reverser inhibited refer to :
>
> - For A318/A319/A320/A321 MMEL 02-78 Page 1 Rev 29
> - For A310 MMEL 02-78 Page 1 Rev 17
> - For A300-600 MMEL 02-78 Page 1 Rev 15
> - For A330 MMEL 02-78 Page 1 Rev 17
> - For A340 200/300/500/600 MMEL 02-78 Page 1 Rev 19

[broadreach]

Local TV news announcing that CGH main runway is to be shortened by 300m to accomodate 150m overrun patches at either end. I haven't seen details yet but presume these are of the crushable concrete variety already discussed here.

First impression is that this a knee-jerk reaction under strong political pressure to show "we're doing something". Now that we have some Brazilian pilots on the thread, their opinions would be interesting.

[Lemurian]

marciovp'

1. Why the plane was loaded with more fuel than needed?
2. Why the plane was carrying more people than it was certified for? (It was certified for 162 seats and had 174 seats).
3. Why did this plane landed with a locked out reverser in a short, wet, slippery runaway?
4. Why didnīt AB make it mandatory for all A320s to have the new software that keep advising the pilots of one TL not being in Idle or Rev.
5. Why this particular plane has had now three similar accidents by six pilots making the same mistakes?
6. Why ANAC made a rule that planes should not land in Congonhas with one reverser locked out and then withdrew it?...
7. Why Congonhas runway was liberated in a rainy day without grooving?
And so on.

Some of these questions have been answered before on this very thread :

1. They were tankering, apparently in order either to save on fuel costs because jet a is more expensive at CGH or saving on turn-around time, or both. Normal practice on all airlines. Whether it was reasonable or not is not for me to say. What I know is that performance-wise, there were no objections.

2. Careful, here. According to FAR 25.807, the seating capacity for such an aircraft, equipped with 4 Type I and 4 Type III exits is 179 seats, crew members excluded. Therefore, the number of seats was correct for the configuration.

3. You pose a question on TAM procedures and policy that I'm not in a position to discuss. Once again, they had the performance to land on a wet runway such as CGH 31. On the other hand, was the *slipperiness* taken into account ? In all probability, no but a definition of slippery in terms of friction. braking action...seems to be lacking on that airline FCOM.
If you are interested, you could have a very careful look at this BAC powerpoint presentation on

Landing on slippery runways

4.Airbus Industrie -AI- has absolutely no control on mandatory procedures. The certifying authorities do, and that will be the local DGCA services or their equivalent. What I know is that the implementation of this new warning was not well received by a great number of customers' technical services as inducing even more confusion than the old software. They went instead into more training on similar situations.

5.That's also a training question or a question of training. Depends how one looks at it. To concentrate on a perceived aircraft system fault amounts to putting the blame for a flat note on the piano instead of the pianist. I have shown, along with Christiaanj that very comparable events happened on 747s without anyone yelling for a change on its throttle system. Can't have it both ways.

6. and
7. Both belong to Brazilian politics that I am not ready to discuss. Let the politicians deal with them after the report has been published.

Another question you could have asked - based on the FDR - is about the preflight preparation for a landing at CGH. As the previously recorded times of landing and takeoff from the previous station are just about 31 minutes apart, including taxying in and out, was all consideration due to the reported poor braking taken into account ?

Or -second question- what destination was on the flight plan. Was it really CGH ? Was it GRU (as the initial conversation with the flight attendant suggests ) ? The implications are not equivalent, are they ?

Technical sources, please. With actual experiments preferably.

PBL is referring to the deceleration achieved by this aircraft taken from the FDR print-out. A very *poor* braking indeed.
Regards.
Lemurian

[Rob21]

Maybe this is an attempt to force heavy A/C to operate in/out of Guarulhos (Cumbica) and Viracopos (Campinas).

Better start to train those tractor drivers on how to pull airplanes out of the gravel, because companies will continue to "push" the envelope and land at Congonhas.

Airline companies should bring back the Electras, they can operate on the "new" CGH 300m shorter with no problem.

[flyingnewbie10]

PBL is referring to the deceleration achieved by this aircraft taken from the FDR print-out. A very *poor* braking indeed.

That's what I thought.
However if (if) he was based on the FDR the information might not be accurate as we still don't know how slippery the runway was.

What we know is that the crew thought that the runway was slippery. And this could explain their hesitation to apply manual braking before spoiler extension if after all such hesitation showed up to be expected from a crew in the same situation.

[marciovp]

Shorter runway and number of seats

Careful, here. According to FAR 25.807, the seating capacity for such an aircraft, equipped with 4 Type I and 4 Type III exits is 179 seats, crew members excluded. Therefore, the number of seats was correct for the configuration

Thanks for your answer and dialog Lemurian. I acknowldege that you know a lot more about this airplane and aviation than I do. For me it is a privilege to be here. What I said is that ANAC (National Agency of Civil Aviation) certified that plane to fly with 162 seats. Also if there was some plans for the A320 to land at Congonhas in a raining slippery night efforts should be made to make the plane as light as possible, no?

Insofar as Congonhas, just saw the Minister of Defense. Yes they will use 150 meters at each end of the runway as escape zone with soft cement. The Minister said that one consequence of this change is that only lighter airplanes will be using the airport (not clear which ones are those) with the shorter runway (I believe 1940 meters minus 300= 1640 meters). The big planes that lad there? Boeing 737 (400 to 800), A320, Fokker 100...

Yes, it is true it seems. Besides having a shorter main runway, the auxiliaru runway also will go to 1250 meters, with escapes of 120 meters in both ends.

This decision was made by the Minister of Defense and the Air Force. Congonhas no longer will be a hub and 737s and A320s will not land there unless they manage to have less weight with fewer seats and lessa cargo, the note said.

[PBL]

Originally Posted by Rob21

But as for now, I don't agree when you say that during flare engine #2 had significant forward thrust.

I regard an EPR of nearly 1.1, and then rising, as showing significant forward thrust.

PBL