Brazilian air crash

SN30952 · Post by **SN30952** » 18 Jul 2007, 19:30

Who heard of the ”Kollerud method”?
SAS started 1946 to operate Douglas DC-4 airplanes on their newly opened Scandinavia - New York route .
For maintenance reasons SAS had occasionally to operate the DC-4 airplanes into Oslo's Fornebu airport. The main runway at this airport was then only 1200 m long with steep lopes at both ends. In order to avoid accidents at his airport the Airport Manager, Ottar Kollerud, started measurements of friction on the runway surface under winter conditions before DC-4 operation was to take place.

Mr. Kollerud developed a method for friction measurements. According to this method a big truck was loaded with sand, accelerated to 30 km/h when full brakes were applied resulting in locked wheels. Time and/or distance to a full stop were recorded.

From the recorded time, T, and distance,S, retardation, r, can be calculated:

r = V/Tr = V2/2S(r: m/s², V: m/s at brake application, T: s, S: m)

Kollerud reported the retardation in m/s².
By test flights made by SAS it was found that the recorded retardation determined according to the formulas above corresponded to approximately half the value for the retardation of the airplane. Test runs were made with DC-4's. Later tests and calculations showed that this was valid also for a lot of other airplane types.

The Kollerud method for retardation measurements is included in the ICAO Airport Services Manual, ICAO Doc 9137-AN/898, Appendix 5.
The method is somewhat modified.
In the ICAO document the friction coefficient,µ (mu) is calculated.
This is obtained by dividing retardation with g = 9.81 m/s². Simplified corrections are given to convert the measured friction values from µ (mu) skid toµ (mu) max.

Mr. Kullberg introduced his Skiddometer method to record runway friction.

The Sao Paulo obviously had a high skid factor.... But why didn't the airport authorities not adhere to the ICAO Airport Services Manual?

It is known that in Canada they not cut grooves because they provide no extra braking power in winter, and they require snow plows to use Teflon blades to avoid tearing up the grooved runways. And grooves make snow removal expensive and slow.
But it never snows in Sao.
Note the US is pressing ICAO worldwide to require grooving because it makes braking power much better in summer rainstorms.

Runway overrun standards
That is the area and length of the ground at the end of a runway that can support an aircraft that does not stop in time.
How is that @ Sao's airport.
I'm afraid it s not existent.

What about a 'zandbak'?
Some airports are going beyond overrun areas, and install a system called EMAS, for Engineered Material Arresting System, at the ends of runways. This is material which effectively stops an airplane as if it had run into deep sand, as installed John F. Kennedy Airport.

And the last question.
Why does such airport not have a 'zandbak'?
Maybe because Latin machos do not play in a 'zandbak'?

SN30952 · Post by **SN30952** » 19 Jul 2007, 09:15

sn26567 wrote:Yes, but when the pilot saw he was skidding he tried to take off again.

The BBC says there are videotapes and that there are indications of that, indeed:
A previous aircraft, came down the runway in 11 seconds, the TAM A320 did travel the same distance in 3' (three). That would be an indication, the A320 was ... accelerating.
A video footage is said to show the final moments of the Tam flight and another similar plane which had arrived earlier.
As the plane careered towards a busy road the pilot tried to take off again, but failed, sending the craft crashing into a fuel depot and cargo warehouse, where it burst into flames.

I looked at this tape, but I did not see any rotation. See Globo TV

earthman · Post by **earthman** » 19 Jul 2007, 11:37

AMS does not appear to have any grooving on the runways, is that correct?

SN30952 · Post by **SN30952** » 19 Jul 2007, 11:43

Deux Français se trouvaient à bord de l'Airbus A320 de la compagnie brésilienne TAM qui s'est écrasé mardi soir près de l'aéroport de Sao Paulo, a annoncé mercredi le ministère français des Affaires étrangères.
En outre, un troisième français, qui se trouvait sur les lieux de l'accident, est porté disparu, selon la même source.
It was first said only two foreigners were on board, two non-Brasilians.
The two on board are of course on the PNR*, the third one was on the disaster scene.

*PASSAGEIROS DO VÔO JJ 3054

blackhawk · Post by **blackhawk** » 19 Jul 2007, 12:05

Video: http://www.bbc.co.uk/mediaselector/chec ... =1&bbram=1

David747 · Post by **David747** » 19 Jul 2007, 12:22

It seems that A320 was attempting to take off again, and could not gain altitude. That is speculation from what I'm hearing from the BBC and other news sources. Either way, very tragic accident.

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 19 Jul 2007, 13:27

From the angle I see it, it seems the approach was faster than normal and that there was an attempt to take-off again... which was the pilot's decision.
It is a bet they had to take and they've lost it.

But if flying starts to become a matter of bets, there seriously is a problem...of safety

SN30952 · Post by **SN30952** » 19 Jul 2007, 16:14

FLY4HOURS.BE wrote:But if flying starts to become a matter of bets, there seriously is a problem...of safety

I knew Football Betting was in, in Brasil.
There was a time, people took an insurance when they took a flight, FLY4HOURS.BE
Authorities should decide on these two questions:

what risks are acceptable.

are risks acceptable.

And I feel also the Passengers Interest Associations failed and still fail to warn about the dangers of and the insufficient safety of some airports.
eg: International Airline Passengers Association IAPA did not emit warnings, as far as I know....
I checked their website on 'Airport Safety'
Here is the reply:
0 entries match 'airport safety'.
Try using a less specific phrase to widen your results.

EU decided on a ban on airlines.
Who dares to makes the airports blacklist?

Note: LZ readers will have noticed how heavy the reactions are already when the item airport is discussed. Airports are the cathedrals of a new religion, who dares to criticise these temples, can reckon with heavy headwind from self declared high priestess & high priests.

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 19 Jul 2007, 17:01

There was a time, people took an insurance when they took a flight, FLY4HOURS.BE

What's your point with that? I mean "flying" from a cockpit point of view not a pax p.o.v. Insurance has little to do with what I ve stated...

Anyways I agree that the airport is very nasty, but if another A320 manages to land safely 2 minutes before with a safe margin, why couldn t this one make it?
IF they intended to take-off again which is the last thing an experienced pilot would intend to do, when did this intention arise? After seeing that the machine wouldn t stop? Or did they already feel they were a bit fast on approach and gave it a try anyway with the option of a touch-and-go in their mind?
Was there any mechanical failure?

The runway length was 6362ft which is aprox. 1900m.
If the security camera's are coordinated (they seem to be), we will see the A320 rolling for about 23 seconds on the runway.This means it had an average speed of 297km/h...about 160 knots... which is about enough to lift up the plane...

There also is that little explosion at the end of the runway...

Homo Aeroportus · Post by **Homo Aeroportus** » 19 Jul 2007, 17:20

FLY4HOURS.BE wrote:
IF they intended to take-off again which is the last thing an experienced pilot would intend to do, when did this intention arise? After seeing that the machine wouldn t stop? Or did they already feel they were a bit fast on approach and gave it a try anyway with the option of a touch-and-go in their mind?

The pilots, both ranked as "Comandante" (TAM Informa 18/07), had each logged more than 14 000 hours.
I would assume they had landed a couple of times before at Congonhas and were perfectly aware of the zero-tolerance of a hot approach and equally familiar with TOGA procedure on an Airbus.

So until proved wrong, I would suggest we give them the credit to have done what needed to.

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 19 Jul 2007, 17:49

So until proved wrong, I would suggest we give them the credit to have done what needed to.

The A320's have been added to TAM's fleet very recently (since last year, I think). 14000hours with how many on type?

Because if they knew their airplane so well, they would have known it wouldn t make it back into the air...

I would assume they had landed a couple of times before at Congonhas and were perfectly aware of the zero-tolerance

So how would you explain this happened?
What would be the tolerance of an aborted landing?

One thing is sure, if they had pushed on the brakes until the end, some might have survived and/or the collateral damage would have been smaller.

RC20 · Post by **RC20** » 19 Jul 2007, 19:05

Frankly this sounds a great deal like the Chicago crash of S.W. airlines.

Trying to put a large aircraft into an already marginal runway, and with a couple of things going wrong (higher than there should be landing speed and bad surface) there is simply no latitude for that. When each landing has to be perfect, you are looking at a disaster.

There should be an overrun on runways like that (anywhere) or they should be restricted to aircraft types that no matter what happens, they have adequate landing distance (turob props in this case).

fokker_f27 · Post by **fokker_f27** » 19 Jul 2007, 22:24

I say this airport must close or take safety measures which would be nearly impossible considering the location of the airport. The troubled history of the airport has proven that it's simply too dangerous for large jets because of the buildings nearby and the short runway. The BRA 734 was just lucky that he didn't hit anything, you could see on the picture how close he was to the end of the taxiway.

bits44 · Post by **bits44** » 20 Jul 2007, 06:20

Aircraft found to have a deactivated thrust reverser!

http://www.forbes.com/business/feeds/af ... 34094.html

SN30952 · Post by **SN30952** » 20 Jul 2007, 08:37

Runway overruns account for 29% of serious accidents worldwide in the past 12 years...
And why would that be?
A failing reverse system in this case.
São Paulo's Congonhas airport's runway is shorter than average, but well within the stopping requirements of jets like the A320.
But this A320 was flying with a fault in its equipment

A problem with the reverser was detected on July 13 and that according to Airbus guidelines the plane should have been checked within 10 days of the discovery.
How is mañana in Portuguese? Em português: amanhã

Did you notice how people, also in this Forum, accused all and everything, adding to the fact that an accident never comes alone nor from one reason only.

Indeed, we have to divorce ourselves from preconceived ideas to produce credible contributions.

euroflyer · Post by **euroflyer** » 20 Jul 2007, 09:14

SN30952 wrote:A problem with the reverser was detected on July 13 and that according to Airbus guidelines the plane should have been checked within 10 days of the discovery.

From a pax point of view: I cannot see the sense behind this 'rule' (if it is cited correctly). So it is ok to fly without reverser for 10 days?? Why 10, why not 12 or just 8?? My opinion would be: 0 days (and not just because of the tragic crash now in Brasil.

I know the reverser is not the only way to stop an aircraft on the runway, however, who would understand if a rule would say you could drive your car with brakes working on just 1 wheel for another 10 days down the motorway before you have to bring it to the garage?

Airport with relatively short runway, no extra space for aircraft to stop after overrrunning, bad wheather, runway without adequate surface, aircraft with defect at one reverser, ... it sounds like one could have seen this accident happen before

. May be it would theoretical still have been possible to land safely, I do not know this, but the chances were obviously much smaller than normally.

I hope the people responsible at TAM will have to answer some questions (at least it should have been possible to let this specific A320 with the defect reverser operate on routes to other airports, with longer runways, until it has been fixed again?). And, sorry, if the pilots were aware of all these factors (and I guess they had to be aware) I cannot say they did a perfect job, if they still tried to land in these conditions, accepting, to say the least, a quite high risk. I think they could have requested to be redirected to another airport at Sao Paulo?

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 20 Jul 2007, 09:16

Did you notice how people, also in this Forum, accused all and everything, adding to the fact that an accident never comes alone nor from one reason only.

I keep my point of view 8)
The crew knew that the right thrust reverser did not work from before the flight, which makes it even worse!!
They should not have accepted to take the plane in such conditions knowing they were to land on a short runway which was obviously wet that day...
Plus they took the wrong decision to accelerate the plane again instead of forcing the brakes...it would have crashed but with less damage

Homo Aeroportus · Post by **Homo Aeroportus** » 20 Jul 2007, 10:29

[quote]
They should not have accepted to take the plane in such conditions knowing they were to land on a short runway which was obviously wet that day...
[quote]

The aircraft was flyable per the airframe manufacturer.

If you let a pilot decide not to fly because he "does not accept this", then you open the door to the possibility of overriding the same Operating Manual in the other direction and decide "I can make it".

I agree that one reverser inop may be touchy if the other is deployed and there is a strong cross wind but the landing distance is calculated without reversers.

Actually, I often fly with an airline that never use the reversers on landing their 4-engine jets.

SN30952 · Post by **SN30952** » 20 Jul 2007, 10:35

FLY4HOURS.BE wrote:They should not have accepted to take the plane in such conditions

Point. That is the responsibility of the cockpit crew. In this case the two 'commandantes'
But also of the line mechanics.

FLY4HOURS.BE wrote:Plus they took the wrong decision to accelerate the plane again instead of forcing the brakes...it would have crashed but with less damage

A wrong decision in the face of death, who are we to be judge on that.

The question is: what are the risks that can be taken? Because risks are taken, (not all the time).
Or in other words, what are the risks a passenger should consider when boarding an aircraft?

Homo Aeroportus · Post by **Homo Aeroportus** » 20 Jul 2007, 11:03

A wrong decision in the face of death, who are we to be judge on that.

Absolutely agree. We just don't know what these guys had to face. Let's be careful with these statements concerning they did wrong or they did right.
Remember AF at YYZ?
The press (and the Pax) took the crew for heroes to have made a "successful crash" while it seems they were not "top notch" in their handling the landing.

Or in other words, what are the risks a passenger should consider when boarding an aircraft?

Maybe that by I am part in "creating" this risk:
by flying to this (questionably safe) destination I support its existence.

Congonhas is very conveniently located if you want to go downtown.
25 years ago, the only alternative was Viracopos/Campinas that was nearly half a day away by "road".
Then they rehabilitated Cumbica AB to become Guarulhos, much closer to downtown but still, Congonhas remains favorite.

So I feel I have a responsibility is keeping CGH open BUT the CAA is there to ensure that this is not unsafe.
Type of A/C operating, R/W contamination, aircraft maintenance, pilots, ...

Aviation24.be

Brazilian air crash

”Kollerud method” and the 'zandbak'.

What are the risks that can be taken?

Re: What are the risks that can be taken?