French Concorde crash

[jcjeant]

Hi,

But not to the same catastrophic extent

Indeed .. the Washington even was not so catastrophic .. but anyways the plane was scrapped.
And the remplacement plane was ironically the one who crashed in Gonesse.

[jcjeant]

Hi,

... [BA] engineers have begun fitting [Concorde] with new linings to its fuel tanks and shielding wiring in the undercarriage areas.

The new fuel tank liners, (which are similar in appearance to seed trays) - manufactured by EADS, the former Aerospatiale, in Toulouse - are made of a kevlar-rubber compound and cost around £17,000 Each. They have been designed to contain the fuel should the wing skin be punctured,

That demonstrate they where full aware of the danger represented by the problems in case of fuel tanks puncture ...
This danger come from the design of the Concorde ... gear .. fuel tanks and engines locations .
The Washington event was a eyes opener.
The catastrophe was fully predictable .. what was not know was where and when.

[md80fanatic]

The form and shape of the titanium strip found match exactly the tyre cut pattern on the burst tyre for a very large 70lb chunk of rubber that also matched the indentation on the wing.. They put the strip up against the rubber and it followed it exactly. That evidence is pretty clear in that regard.

I am not so sure about the ability to accurately reassemble a burst tire using a piece of rubber that is said to have penetrated fully two wing skins and at least one full fuel tank, and finally land on the runway still with high momentum. To say the edge line perfectly matches a bent up titanium strip is near ludicrous to suggest.

Tire bursts are chaotic events at the moment of the burst. Forces are high enough to penetrate as was displayed 6 times before. What makes one believe that a force strong enough to penetrate the wing/tanks would not be enough to further mangle a titanium strip that is said to have been at the center of the event? Would a pre-burst strip topography precisely match the post-burst tire pattern? No one can possibly discern such. (except for the French apparently)

[onetrack]

Fargoo, thanks for the excellent pics and report link, which I wasn't able to find initially.

The simple fact remains that it is obvious the Concorde was built with inherent minimal tyre reserve strength.
The Concorde tyres operated at 225-230 psi (15-20% more pressure than a 747-400 tyre).
They were tasked to run to over 200 kts at VR (as compared to a 747-400's 163 kts).
The Concorde tyres were a smaller diameter than any other comparable aircraft.
The wing sheeting on Concorde was thinner than comparable aircraft.
The fuel load was enormous - 26,286 Imperial gallons (119,500 litres/95,600 kgs).
The tyres were tasked to operate at FL60, leading to even higher tyre stresses, than other aircraft tyres.

There were 70 Concorde tyre burst events between 1976 and 1999. 7 of those events resulted in metallic shards piercing the fuel tanks. The metal came from the water deflectors on the undercarriage. BA added additional deflectors to their Concordes to deflect tyre and water deflector shards... but AF didn't.

And even after all this... Mike Bell, the CAA's head of design and production standards, states: (quote - late Aug, 2000) "This is unique. We could not believe that a single tyre failure could lead to the loss of an aircraft"...

This... despite the well-known, and often-repeated warnings of the massive explosive power of an instantaneous tyre burst... reported to be the equivalent of "4-5 sticks of dynamite".
It's obvious the powers-that-be, never even remotely considered runway debris as a serious risk to Concorde operation.

In the case of the Concorde, it appears that there was a long-held and over-ruling belief, in important aviation quarters (and not just AF)... that there was no serious tyre damage potential... and no attempt was ever made, to examine the all-too-obvious disaster potential... from tyres that had virtually no reserve strength in their design, from day one.

Tire Explosions Can Discharge Energy Equivalent to Dynamite | Air Safety Week | Find Articles at BNET

[crazyaviator]

In the case of the Concorde, it appears that there was a long-held and over-ruling belief, in important aviation quarters (and not just AF)... that there was no serious tyre damage potential... and no attempt was ever made, to examine the all-too-obvious disaster potential... from tyres that had virtually no reserve strength in their design, from day one.

Reminded me of the shuttle disaster The leading edge was perforated by ice accumulation from the fuel tank,,,, everyone also thought it couldnt have the force necessary to break the LE material,,,but after the simulation tests, everyones jaw dropped!! Physics and peoples opinions DONT MIX . Human nature is NOT proactive by nature but rather it is reactive !

[Coffin Dodger]

Forget asked re Concorde in-flight wing fire (post #113):

can you point to a report on this? All seems a bit unlikely to me.

http://www.aaib.gov.uk/cms_resources...pdf_029047.pdf

[AlphaZuluRomeo]

Well... First post here, so hello everybody

I'm a French national, and a bit astonished (to say the last) by the amount of french bashing around here, often "backed-up" by inconsistant / irrelevant / wrong "technical data".

I won't try to answer to those who make soooo intelligent comments, except to ask them, perhaps :
- to look by themselves at what can occur in their countries sometimes, and
- to read the public material available on the accident.

I would like to thank, on the other hand, the posters who wrote interesting, informed & relevant posts.

On the topic, now :
I'm not confortable with the verdict of the court. I do think "french interests" (to bee precise : french administration (DGAC, BEA), industry (Aerospatiale/EADS), and operators (AF, ADP)) were somehow overly protected : Some of them do share responsability of the fatal events (Reason's model), for not having taken into account the previous incidents. [edit] My mistake, I should have read better : Eventually the court DID take that into account, with the 70%-30% amount sharing.
However, I do think Continental's way of defending itself (abstract : "it's not our fault, the plane was already burning") is based on biased facts/beliefs and/or unconvincing testimonies (**), therefore being far(ther ?) from the truth...

Cheers,
AZR

(*) If anybody's got a link to a list of testimonies including the professional qualities and position at the time of the accident of the witnesses, please provide it : I remember the french TV reporters "contre-enquête" but had found it unconvincing...

[PT6fixer]

With apparently several burst tire incidents it is a wonder not more has been done to protect the tanks or manufacture other stronger tires prior to this incident.
And can anybody tell me why the mechanic in Continental ultimately is the guy being sentenced?
He must have a maintenance manager or supervisor that oversees his work.
And unless he has kept it out of sight of those very people i fail to see why they haven´t gotten a sentence too?
Instead of the buck stopping at the very top, it has stopped at floor level in this case.

[Nick Thomas]

md80fanatic
Am I correct in assuming that you believe that the tyre fragment penetrated the wing? My understanding is that it did not as the impact caused a percussive shock wave in the wing tank. Please see PBL's post 38.
Therefore I submit that it's possible to examine the tyre fragment to determine if the cut was caused by the titanium strip.
If you disagree with that statement it would be helpful if you could back your opinion up with verifiable facts.
Regards
Nick

[forget]

Thanks CD, ozaub inferred that the incident was spontaneous when, in fact, it came about through damage to the wiring - which rather kills his suggestion that the aircraft needed re-wiring.

In 2001, routine inspection of the wing structure had detected cracks in the area of spar 66, Figure 2, and in order to complete the structural repair, it was necessary to disturb the wiring. It is likely that in reinstating the wiring the possibility for the chafe to occur was introduced.

[Bergerie1]

PBL (your post 112)

Thank you for being the calm voice of reason. Far too many posters sound off without studying the facts.

[cwatters]

MD80Fanatic -

They did many tests to see of similar strips could cause tyre damage. . See page 98 onwards..

http://www.bea-fr.org/docspa/2000/f-...-sc000725a.pdf

They also found rubber from concord tyre in the rivet holes on the strip.

[lomapaseo]

Pros and Cons

Some Pros and Cons to ponder

From a data standpoint (historical)

Runway debris is always a risk

The risk decreases with runway usage (stuff blown off runway by jet exhaust etc.)

Tires blow out due to debris often whether made out of titanium or not

Tires go up and hit wings often

Metal pieces of blown tires are less often encounterd but when they happen they do put small holes in wings

Small holes in fuel tanks due to blown tires are rare

Fuel leaks from small holes in tanks being ignited at takeoff speeds are quite rare

Large holes in fuel tanks due to blown tires are quite rare

taking the combinations together (as in this accident) were arguably not forseeable in the life of the fleet.

Hindsight of course can always predict the past

The trial was unfair in that it failed to consider probabilities and sellected only a single probable contributor for blame.

[Diversification]

Drilling in titanium

CJ

I have drilled many times in titanium and its alloys and also machined it in lathes. No problem if one uses standard hss type sharp drills. We usually squirted some denaturated alcohol on the drill and used not too high rotation speed. Very much like drilling is some alumina alloys.
However, if the titanium had been heat-treated it had a very hard surface which usually was removed by etching before machining. The most spectacular thing is that when you operate your tools at too high speed, the removed matter may start to burn with a strong white light and emission of white smoke.

Regards

[ChristiaanJ]

lomapaseo,
Finally another sensible post, thanks.

My own take on the matter, for what it's worth.

The tyre burst itself did not cause the crash.
It caused a major fuel leak.
If that leaking fuel had not caught fire almost immediately, the outcome might have been very different.

The accident was a combination of events in a chain, as nearly always.

There were two major events:
* an unprecedented tyre burst causing a major fuel leak,
* the leaking fuel caught fire.

All the other issues, dragged out endlessly, merely determined how exactly the subsequent events evolved.
None of them would have caused the crash by themselves.
None of them would have done anything other than move the crash location slightly........

CJ

[wings folded]

lomapaseo

The trial was unfair in that it failed to consider probabilities and sellected only a single probable contributor for blame.

No, it did not.

The very reason for the trial was to establish what caused the loss of life of the victims.

The decision was made by a panel of three career judges (not elected muppets; in fact people who have gone through a selection process which would have left you and me gasping at the roadside) after 3 or 4 months of evidence and a 6 month period of reflection to come up with the judgement.

One of your cherised national carriers was found to have been faulty. And one of its employees.

The sanctions called for were at the best modest.

Euro 175,000 was demanded against Continental. Euro 200,000 was awarded.

The mechanic's sentence in prison is suspended, as demanded by the prosecution. He would never have been rendered to France to serve a jail sentence anyway, since your nation does not extradite its nationals.

Trials are designed, indeed meant, to clarify what happened. That is what occurred.

[bearfoil]

ChristiaanJ

With respect, I think it is popular to subscribe to "Holes in Cheese". I think it not wrong, but a titch misleading. The first hole is what is known in some approaches as the procuring cause, The rest of the holes really are more like "results".

In this accident, as we see here, the Titanium is the procuring cause only if one wishes it to be. Nothing of any conclusive nature rising to acceptable thresholds for Criminal prosecution exists here, IMO.

all respect, Sir

Bear

[ChristiaanJ]

Originally Posted by Diversification

I have drilled many times in titanium and its alloys and also machined it in lathes. No problem if one uses standard hss type sharp drills. We usually squirted some denaturated alcohol on the drill and used not too high rotation speed. Very much like drilling is some alumina alloys.

Thanks for removing my mis-conception about machining titanium.
It doesn't excuse the mistake by the Continental mechanic, but it does make it a bit more understandable.

CJ

[bearfoil]

Diversification

Are you sure the debris was "burning"? If so, would you be concerned about the part being machined? Could it be atmospheric gases being liberated and then oxidizing?

Would you want an inert environment if "burning" was possible?

I have trouble with Stainless!!!

[wings folded]

Mr Bear

Nothing of any conclusive nature rising to acceptable thresholds for Criminal prosecution exists here, IMO.

In your opinion, (if I understand "IMO" correctly), there should not have been a trial at all.

I have some experience of the insurance consequencies of the loss of an aircraft.

A lot of my experience is US based

A lot is European based

Part of that is French based.

Each nation applies its own legal regime to the problem.