Please help me out here - is that different to the kind of sideslip referred to on p153-154?

Hi

My position is to foreclose all positions except the true one...:ok:

So basically I am looking at everything that is visible, and reported, to see if anything is left out....

Did you have a chance to view the runway photo of the carbon trail/kero stain?

Because if BEA are referring to the tyre marks prior to burst, these must be visible, are they the ones showing two trails of dark rubber, interrupted in a seemingly consistent way?

i feel a resistance in the force; one hopes I am not too annoying.

Yes.
Fig 73 looks at the effect of malalignment of a bogie with the aircraft following a straight line path. Note how the RH gear is still lined up with the aircraft track.
The French version of the report describes this state as ripé which is simply slip.

If the aircraft as a whole was angularly displaced relative to its track the RH gear would also be showing slip. That is what I mean by sideslip and the French term would be dérapage.

Once again confusion from English translations!

Anyone know why BEA did not translate Appendix 6 mentioned up-thread?

Hi Lyman
If as you ask we leave aside the titanium strip and instead assume that there was an engine failure(not caused by FOD) then if I understand correctly you are of a view that the missing spacer will cause a shimmy which makes the FE think that he must shut down the engine immediately. Then the loss of that engine results in the plane not being able to climb away safely and so we end up with the same tragic outcome.

Now we have an engine failure then in this hypothetical case, the reason for the failure would have to be investigated and also the possibility that the engine was switched of because of the failure must also be considered. So there are a lot of new things that have to be considered.

I presume (correct me if am wrong) that you think the FE would not have shut down the engine just based on the shimmy, but he would also need to have other indications of failure.

Unfortunately for your hypothesis to have any chance of being proved, we would need to know exactly what the FE was thinking as the accident unfolded.

Having read CliveL's helpful posts and considering what you have said I am still of the view that the report gives us the best overview of the accident.

So. I will offer an evidence for oscillation in the early roll.

Note the paired deposits of rubber through the stain and beyond. The two men are standing directly on each individual mark.

Four tyres are making two trails, as they would do. They are soaked in kerosene, which has a marked affinity for synthetic rubber. It wets and remains wet. This helps the marks' visibility. We see that in between pairs of black deposit, there is a portion of skid free concrete.

This is the time when the four tyres are aligned with the a/c motion. the following pair of black skid mark is their misalignment with the aircraft, and the four tyres are skidding in kerosene wetted Elastomer. due to lousy traction, there is no net effect on heading.

The truck then rebounds, returns through the zone of alignment, and deposition of rubber stops, until the truck continues into the misalignment, deposits black, and repeats, disappearing into the soot stained photo.

The oscillation is relatively harmonious, by symmetry of the paired deposits.

Work for you?

Hi Lyman
Thank you for posting your opinion on the photographs concerning the tyre marks. Whilst I accept that the photos are evidence and don't doubt for one moment that you are convinced by your argument but your convection can't change your opinion into evidence. Therefore am unable to accept your conclusions drawn from the photographs as evidence. So that is why it does not work for me.

Lyman,

Forgive me for being thick but what b*y picture are you talking about?

I can't seem to find anything in the BEA report that has two men standing on tyre marks.

Sorry.....

Was Continental Responsible For the Concorde Crash? « Heritage Concorde



the "other runway pic."

rgds.

If you're referring to the second wide-angle shot where there are several vehicles and men on the runway, the very bottom of that picture shows the stain from the fuel spilled when the tank burst. The picture itself is taken roughly in the direction of the takeoff roll from just prior to the unburnt spillage.

Correct me if I'm wrong, but if the tyre burst preceded the fuel leak, would it not be reasonable to conclude that no tyre or debris markings in that photo were made prior to the tyre burst?

[For reference, this picture I'm referring to is Fig. 74 on the report, p.160. I must confess my initial impression was that the resolution was not sufficiently high to determine tyre and rubber debris markings with much accuracy. Additionally, determining the nature of marks within the soot is made difficult, as it appears one of the ground vehicles has inadvertently driven through the soot trail.]

Lyman

Thanks, I've got it. It is fact the same picture as Fig 74 in the BEA report, which I missed..
It looks to me that Fig 24 of the BEA report was taken from just about where the two men are standing together in the picture you are using, but being much closer to the action it shows much more clearly the tyre imprints and tracks.

I recommend looking carefully at that Fig 24 because although you can see the obvious cyclic imprint of the flapping remnants of the tyre if you run a ruler over the line of imprints there is no evidence of lateral oscillations whatsoever that I can see.

Hi Lyman,

This link made me understand why we were in disagreement a bit earlier, on a specific point: We simply didn't look at the same picture. ;)

The pic in the provided link (i.e. Heritage) is indeed aerial & long distance. This pic is from BEA's first interim report (dated December 15, 2000), and was re-published in the final report, as Dozy said just abobe, in § 2.1.3.

But it's not the pic I was thinking about:
Please, do not get stuck on the one page of Heritage Concorde, and refer yourself to BEA's richer final report, § 1.12.1.8 Tyre tracks, you'll find some other pics, that are neither aerial, nor long distance, nor blurry. :)

And as Clive said:
... I would like to insist on the fact that the 2 parallel tracks seen on Fig 24 are indeed from the flapping remnants of one tyre only (the #2 tyre). And show no wobble of any kind.




No, sorry. But if you're struggling to understand some specific part with Google Trad or such a tool, feel free to ask for a free translation (keep it short, please ;)).

20 juillet 1979 : après l’accident de Washington, le BEA, dans une note confidentielle faisait le constat suivant quant à la gravité des conséquences possibles d’une destruction de pneumatique : risque d’incendie, avarie grave de moteur, impossibilité de relevage du train d’atterrissage.

25 juillet 2000 : crash du Concorde F-BTSC suite à l’éclatement d’un pneumatique qui avait provoqué un feu important sous la voilure gauche, une perte de poussée des réacteurs 1 et 2 et l’impossibilité de relevage du train d’atterrissage

29 août 2000 : Les certificats de navigabilité des Concorde sont suspendus par le BEA à cause du risque lié aux destructions de pneumatiques.

Ce jour-là, devant les caméras télé, le patron du BEA persuade les médias du monde entier qu’il vient de découvrir le problème. « Nous avons déterminé que le risque d’éclatement d’un pneu pouvait provoquer des dégâts aussi extraordinaires en aussi peu de temps »

« C’est ça le point important » martèle t’il pour que l’auditoire perçoive bien le message…




July 20, 1979: Washington after the accident, the BEA, in a confidential note made ​​the following statement about the seriousness of the possible consequences of a tire destruction: fire, severe damage to the engine, unable to lift the landing gear.

July 25, 2000: Crash of the Concorde F-BTSC following the bursting of a tire which caused a large fire under the left wing, loss of engine thrust 1 and 2 and the impossibility of raising the landing gear

August 29, 2000: The Concorde airworthiness certificates are suspended by the BEA because of the risk of destruction of tires.

That day, before the TV cameras, the boss of BEA persuaded the media of the world that he has just discovered the problem. "We have determined that the risk of a blowout could cause damage as extraordinary as little time"
"That's the important thing" he insists so the audience perceives the message well

@jcj:

Could you humour me and tell me the sources you're quoting there?

As pointed out up-thread, in the wake of the '79 Dulles incident a modification was made to prevent tyres failing in the same way (in this case by improper inflation). In other instances of tyre failures where the cause was investigated, more modifications were made. It's commonly (and erroneously) reported that little or nothing was done to prevent tyre failures between the '79 incident and the loss of F-BTSC, but the fact is that modification work was ongoing and procedures put in place several times in the intervening years to minimise risk (for example, forbidding use of re-tread tyres, BA's deflector modification and the extra inflation monitoring equipment mentioned above).

All these modifications and procedures, along with the dates they were implemented, are listed in the BEA report on F-BTSC.

Additionally, every prior incident of tyre failure that led to fuel tank damage consisted of debris directly piercing the fuel tank from outside, causing either no significant fuel leakage or minor leakage that presented practically no risk of ignition. The fuel tank damage due to fluid compression happened for the first and only time on F-BTSC. Arguably this should have been considered before, but it was a little-known phenomenon at the time.

Hi Doze.

In that laudable defence of tyre performance, did you 'forget' to include the years tyre incidents/failures were simply not reported?

I wouldn't characterise it as a "defence", simply a statement of fact. If you could enlighten me as to any evidence you have of tyre-related problems not being reported, that would help.

the BEA, in a confidential note
The source is the Concorde trial notes
For the video .. the source is obvious
All this merely shows that the BEA sometimes exercise intellectual dishonesty .. no more .. no less
BEA (in the video) cites reasons for ground the Concorde
BEA cited the same reasons long before in a confidential memo .. but had not decided to ground the Concorde (why confidential .. and why not make a recommendation for ground the Concorde ? )
The BEA's note in 1979 shows that the accident was foreseeable ... but in fact (in 2000) .. it's show to the public that Gonesse accident is a surprise .. it was not foreseeable (they discovered the reasons by primary investigations after the crash) .. nobody could imagine that .. etc. ..

The note was confidential, the fix made as a result of it was not. No intellectual dishonesty, just the way things worked in the '70s I suspect.

There was no talk of grounding until 2000 because the failure mode was a new one, and more severe than anyone (including the NTSB and AAIB, who had investigated more tyre incidents than BEA) had predicted.

Hi,

DozyWanabee
I ask again .. why confidential ? what is to hidden from the public ?
What fix ? .. better tires ? .. this was no good results .. tires continued to have problems
Why not the Kevlar fix ? (like made after Gonesse)

This information is all there if you go back over the last few pages of the thread. The public investigation of the Dulles incident would have been handled by the NTSB, not the BEA. In essence, the BEA were simply backing up in private what the NTSB determined in public.

The fix was a device which detected improper tyre inflation (the root cause of the Dulles incident) and fed that information back to the flight deck. The damage to the fuel tank was external and not sufficient to cause fire, very different from the F-BTSC damage which was caused by compression of the tank causing it to burst outwards. This was unforeseen by all. The Kevlar lining was designed to prevent that kind of damage, not the kind that occurred at Dulles.

In fact the Kevlar lining was not strictly required, providing instead a level of redundancy - the post-2000 tyre design would have been enough on its own to get the AOC reinstated.