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-   -   French Concorde crash (https://www.pprune.org/rumours-news/435870-french-concorde-crash.html)

jcjeant 7th Dec 2010 12:39

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 7th Dec 2010 12:48

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 7th Dec 2010 13:48


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 7th Dec 2010 13:53

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"... :ugh:

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 7th Dec 2010 14:37

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 7th Dec 2010 14:46

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 7th Dec 2010 14:55

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".:yuk: :sad:

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. :D

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 7th Dec 2010 15:11

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 7th Dec 2010 15:20

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 7th Dec 2010 15:26

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 7th Dec 2010 15:27

PBL (your post 112)

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

cwatters 7th Dec 2010 15:49

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 7th Dec 2010 16:14

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 7th Dec 2010 16:46

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 7th Dec 2010 16:52

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 7th Dec 2010 17:00

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 7th Dec 2010 17:01

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 7th Dec 2010 17:03


Originally Posted by Diversification (Post 6108525)
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 7th Dec 2010 17:12

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!!! :ok:

wings folded 7th Dec 2010 17:13

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.

infrequentflyer789 7th Dec 2010 17:18


Originally Posted by lomapaseo (Post 6108455)
The trial was unfair in that it failed to consider probabilities and sellected only a single probable contributor for blame.

Agreed but for that last one - it seems they actually did do more than blame the repair and the engineer.

Continental were found guilty as a corporate entity, plus the individual engineer who did the repair. The head of Continental's maintenance was found not guilty as an individual. Concorde designers (and I think a regulator) were also found not guilty of manslaughter as individuals.

However, (and not as widely reported) the court also assigned responsibility for damages - 70% against continental and 30% against EADS as the manufacturer. In doing this they are clearly assigning some of the blame to the Concorde design.

What I do think is unfair, is that this court has (I think) only been able to look at the defendants before it - I don't think they were procedurally able to assign any blame to AF (for example), whatever the evidence, because someone previously decided not to prosecute AF.

bearfoil 7th Dec 2010 17:19

wings

You make a conclusion that "There should not have been a trial".

One cannot know that without the Trial taking place. An indictment is not a proof, and no finding can prevent a Trial from occurring, that is up to the Jurisdiction, (French, in this case).

If you don't like uncertainty, you should practice in Appeals!!

So, on the contrary, I believe wholeheartedly in the Trial's necessity.

bear

ChristiaanJ 7th Dec 2010 17:29

bearfoil,
I think we went through this before.... there IS a difference between a trial and an inquest.

Lemurian 7th Dec 2010 18:13

post 75

NO runway inspections were evident before the accident.
May be they were done when you weren't there?
I know they have been doing three inspections a day for quite a long while, sometimes only two when they had exercises.
Have heard of airport certification

A nation of cowards and liars, I am afraid, with little honour to their name, and little sense of shame.. My personal indictment covers French aviation, and this shameful verdict is in perfect fitting with the French way.
...and you had to work for them for six months !
In your place, I would have voted with my feet a lot earlier.
So who is a coward for not being able to back up his very strong ideas with very strong attitudes ?
Pathetic !

cwatters 7th Dec 2010 19:22

In many countries there is a general principal of law that says that you must take victims "as you find them" (sometimes refered to as the "eggshell skull principle"). Basically it means if you shout BOO at someone and it turns out they have a weak heart and drop down dead you are still considered guilty of manslaughter even though you had no way of knowing that they had such a weakness.

Take Your Victim As You Find Them | ICBC Personal Injury Claims Lawyer Erik Magraken | Victoria & Vancouver Island BC

Obviously you can claim you didn't intend to kill them and that should be considered in mitigation but you are still guilty. It's not the victims fault that they have a weakness.

Capetonian 7th Dec 2010 19:47


Try getting the French responsibles to investigating or admitting to this. Not a chance. A nation of cowards and liars, I am afraid, with little honour to their name, and little sense of shame.. My personal indictment covers French aviation, and this shameful verdict is in perfect fitting with the French way.
My experience too. I have also worked with these people and to the above delightful characteristics I would add that they are lazy and devious, and that's without even discussing some of their endearing personal traits. And I got a ban from JetBlast for saying so but it seems freer speech is allowed on this forum.

DozyWannabe 7th Dec 2010 19:47


Originally Posted by jcjeant (Post 6108062)
That demonstrate they where full aware of the danger represented by the problems in case of fuel tanks puncture ...

Hate to break it to you, but the Kevlar liners were *designed* and fitted *after* the Gonesse crash as part of the return to airworthiness programme applied to Concorde. EADS, being the parent company of Airbus - which at the time held assets of the former Aerospatiale and BAC - would therefore be the logical supplier.

The redesigned tyres actually made the Kevlar liners redundant, but they'd been front and centre of reports into the work done, so they were kept as an extra safety layer.

I've kept my mouth shut on the wonderful Concorde thread in Tech Log, but some of the invective here really upsets me, so forgive me if I repeat what has already been stated but I want to make a few things clear.

Assertion : The court found no blame attached to any French organisation - FALSE.

As has been stated, EADS (as the parent firm that subsumed Aerospatiale and part of BAC) were found partially responsible.

Assertion : There is still reasonable doubt as to whether the titanium strip was the first link in the chain - FALSE.

Every test run indicates that the logical progression of events starts with the strip piercing the tyre. Every potential alternative cause (including the wheel spacer) was run and the chain of events did not fit.

Assertion : Concorde's design was fundamentally flawed - FALSE

Concorde was designed in the 1960s, and indeed was one of the first airliners to have aspects of systems safety incorporated into the design (see the Tech Log thread) - the airframe was as safe, if not safer than any other aircraft of that vintage.

I'm deeply saddened that some of the comments seem to have been written without even a cursory read of the findings, seemingly based on prejudice against the French justice system and French aviation. This feeds into the conspiracy bumpf and doesn't become a forum that prides itself on the professionalism of the pilots and crew that have made their home here.

Stanley Eevil 7th Dec 2010 20:15

Could somebody please confirm/clarify: was an engine(s) shutdown that was still producing significant thrust during this emergency?

bearfoil 7th Dec 2010 20:20

A very stringent effort to merge Concorde with existing technologies and geographies was undertaken, and for the most part quite successful. The Convair B-58 had weenie tyres and quite high launch v's. It experienced, as a military a/c, all that was forties and fifties about aviation.

I am surprised some one takes this trial as an affront to Concorde. I must have been asleep, but how so? She did everything asked, in elegant fashion. Duff tyres, Fred Sanford's aerodrome (s), slop maintenance are not in her quiver, she is the victim of such things, not the accomplice, imo.

Diversification 7th Dec 2010 20:45

Titanium fires
 
Bear
"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?"

That fine and hot threads from machining of Ti in a lathe will burn in air is well known - much like e.g. magnesium, zirconium, uranium and plutonium. Cooling liquid is normally applied to the tool edge to prevent this. These fires almost never spread to more massive parts of the metal. The reactions behind is a mixture of oxidation and nitriding of hot metal. All rather well investigated.

Regards

KBPsen 7th Dec 2010 21:14

I wonder why people keep focusing on the wear strip being made of titanium and insisting it should have been made of aluminum, when it is quite clearly stated in the accident report that it should have been made of stainless steel.

Let me quote from page 105

1.16.6.2 Manufacturer’s Documentation ...The wear strip is made of stainless steel...
And from page 97

...stainless steel whose mechanical strength characteristics are similar to titanium...
That the wear strip was made of incorrect material was of no consequence.

DozyWannabe 7th Dec 2010 21:41

KBPSen:

Note use of the word "similar". That word (ir its French equivalent) would be chosen for a very specific legal reason. If the properties were identical, then your point that the material would have made no difference would be fair.

As it is, the tensile and mechanical properties of titanium versus stainless steel must be different enough that it would have made a difference, otherwise the court would not have come to the conclusion that it did.

KBPsen 7th Dec 2010 21:54

Did the court concluded that it made a difference, or did it conclude that an incorrect material was used? Tests made at Goodyear using both titanium and SS strips seems to indicate no difference in results.

Iron Duck 7th Dec 2010 21:54

FAStoat


Furthermore several aircraft reported an engine afterburner fire on the immediate part of the take off run
Looking at the BEA report, it says on P77 that "The primary and secondary nozzles showed no signs of overheat on any of the engines"; on page 122 "It should, however, be noted that no traces of fire were discovered during the examination of the engines" and on page 134 "The observations and examinations carried out on the four engines brought to light no malfunction of any of their basic equipment or components, or any indication of any behaviour outside of the certificated norms. None of them showed any signs of overheat or overspeed prior to the impact with the ground."

I can't find any mention in the report of other aircraft reporting an afterburner fire. Then again, I could have missed it.

DozyWannabe 7th Dec 2010 22:12

Looking at the event from a systems failure perspective, I would imagine that the incorrect fitting of the part was exacerbated by the part being made of the wrong material. Earlier posts indicate that titanium alloys can be worked in the same manner as stainless steel - if the fact that you're working with titanium is known - but it's likely that it probably caused some problems (see : incorrectly aligned drill holes).

jcjeant 7th Dec 2010 22:20

Hi,


Did the court concluded that it made a difference, or did it conclude that an incorrect material was used? Tests made at Goodyear using both titanium and SS strips seems to indicate no difference in results.
Unfortunately it's in french language ... but this point was subject of a looong discussion between experts , lawers and judge during the trial ........
The complete "minutes" of the trial can be found here:
2 février 2010 Procès du crash du CONCORDE

vapilot2004 7th Dec 2010 22:42

I read this:

As it is, the tensile and mechanical properties of titanium versus stainless steel must be different enough that it would have made a difference, otherwise the court would not have come to the conclusion that it did.
Yet this has remained unanswered:

Did the court concluded that it made a difference, or did it conclude that an incorrect material was used? Tests made at Goodyear using both titanium and SS strips seems to indicate no difference in results.
Meanwhile:

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.
The aircraft was overweight and took off downwind, yet the French court has assigned not one ounce of blame with the operator. Also, what is the significance of the missing wheel spacer? Were they located on the same bogey as the unlucky tire that met with the titanium strip?

DozyWannabe 7th Dec 2010 22:53


Originally Posted by vapilot2004 (Post 6109122)
The aircraft was overweight and took off downwind, yet the French court has assigned not one ounce of blame with the operator.

If I recall correctly, the all-up weight was just outside the recommended numbers, but was within safe limits. Neither the weight nor the downwind takeoff would have changed the outcome, hence AF's actions were not responsible for the accident.


Also, what is the significance of the missing wheel spacer? Were they located on the same bogey as the unlucky tire that met with the titanium strip?
That's a can of worms, because it's central to an alternative theory doing the rounds on the internet, but neither the BEA or AAIB people concerned seemed to think it had any real significance.

exeng 7th Dec 2010 23:12

Stanley
 

Could somebody please confirm/clarify: was an engine(s) shutdown that was still producing significant thrust during this emergency?
Yes it was - according to the tapes the F/E shut down the engine with a fire warning before the Captain asked for the engine to be shutdown.

That engine was producing thrust.

Whether that early shutdown would have affected the final outcome I do not have enough information to make a qualified judgement - but certainly the F/E shut down an engine producing thrust before any command from the Captain.

That action by the F/E was not an action I would have expected from any F/E in another airline that operated the aircraft.


Regards
Exeng

Ex Cargo Clown 7th Dec 2010 23:47

A piece of stainless steel would have done the same damage, if not more.

It may have ended differently as the steel may have take a different trajectory due to the difference in densities, but I'd suggest that stainless steel hitting a wing would be far worse, as it is much heavier.

This all sounds incredibly iffy, and looks like a French cover-up for something.


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