Concorde crash: Continental Airlines cleared by France court

[philip2412]

AZR,Dozy,

Thank you for your kind response !

[Lyman]

Nick, CliveL, Chris Scott.

There is evidence the Bogie was rotating in its horizontal plane. That is clear from the images in BEA.

BEA describes such horizontal articulation as an abnormal.

If in evidence (it is), and also an abnormal, we can assume there is a possibility it played a part in the tragic crash.

Unlike the strip, the condition for wobble was present at take off, iow, part of the compromised airframe, not a foreign piece of debris. The legal implications of presence of inherent vunerability as opposed to accidental accumulation of debris are clear.

"Had no effect..." "Played no part in the crash...". "The lack of the spacer was not relevant..."

All demonstrably untrue statements.

Can the misalignment of the left main landing gear be explained in ways that do not involve the missing spacer? Certainly, but those postulates do not eliminate questions that seriously compromise any legal action Air France may entertain against Continental (United/Continental)......

thoughts?

CliveL.... The side loads provided by the misaligned bogie are apparent in the photography. What affect?

There are clues in the record of ruddering by the Captain. Nx would be conclusive, but Captain's inputs as explained in the text of the BEA seem tentative, given the extent of the excursion, and irregular, though the heading seemed consistently left in direction and rate.

There is a possiblity the bogie played a part in the Captain's perception of yaw? The a/c was not answering the right ruddering, yet three times he returned the pedals to neutral? Once he returned to 10 right, from 20?

[CliveL]

Lyman

You can find Nx in either in Section 1.16.13.2 of the BEA report or, more exactly, in Fig 1 of Annexe 4p of that report.

The side loads provided by the misaligned bogie are apparent in the photography. What affect?

Now you are just putting back to me the question I asked you in an earlier posting...

Shimmy, as I understand it, is a cyclical rotation of the wheels about the main leg. Again at the time we are talking about, the aircraft sideslip was 3 deg. Allowing for +/- 3 deg oscillation because of the missing spacer that would mean the wheels oscillating between zero and 6 deg would it not? Why would the time they were at less than 3 deg not offset the time they were at more? Or in other words, why should shimmy change the average force?

But if you are going to claim that the absence of the spacer had a significant effect on the outcome then you really should provide some more quantitative arguments than anything written so far. Everything I have seen and such calculations as one can make are consistent with the effect of the spacer being rather small - well actually I would say very small.

[Lyman]

Thanks CliveL, your response is appreciated.

Your question is a good one, and I would like to offer that the quantitative component should have been done by BEA in the first place, after all, it is their photography.

I have offered possible approaches to glean some understanding of the affect of tyre rupture, and my suggestions have been ignored. Likewise, an attempt to quantify would be based on data supplied from BEA, data I believe is lacking in sufficiency.

It is BEA who proffered the photography, and begged the work, then did not perform it. Neglectful.

It was BEA that exonerated any complicity of the shoddy Mx by AF. Presumptuous.

It was BEA who did not provide the chemical analysis of the rubber that may have proven the Titanium had been present in the tyre's carcass. In neglecting even the attempt to prove conclusively the strip was involved, they demean the discipline itself. Lazy.

It was BEA that neglected elimination of material other than Titanium as the cause of tyre rupture, Cowcatcher/mount?

Was the area of the truck's mount inspected/analysed by BEA for abnormal wear? The landing gear had travelled several miles carrying two hundred tons, was the spacer's saddle worn?

Was the #2 tyre studiously tested for weakness, as it was two thirds through its useful life, and may have acquired weaknesses unrelated to FOD? Were the other three tyres on the left bogie scrupulously inspected for evidence of misalignment of carriage?

Has anyone found an opinion on why the Captain's rudders were not planted full right? And held?

The report can be described in many terms. Exhaustive is not one such term.

Quote:
Shimmy, as I understand it, is a cyclical rotation of the wheels about the main leg. Again at the time we are talking about, the aircraft sideslip was 3 deg. Allowing for +/- 3 deg oscillation because of the missing spacer that would mean the wheels oscillating between zero and 6 deg would it not? Why would the time they were at less than 3 deg not offset the time they were at more? Or in other words, why should shimmy change the average force?


Shimmy is analogous to a human heart in arrhythmia. A pulse of two hundred, and no blood flows, the pump is stalled. Shimmy means skid, and skid means poor traction, and irregular bite at that.

"Shimmy" makes unlikely any predictable effect of any part (cycle) of the oscillation. Therefore, because the bogie is aligned ("established") part time, one cannot then predict that the corollary alignment is of equal (balanced) force.

Note the shape of the shimmied tyre, number 1. The excursion left is broad, the return to "zero" is sharp, and shortlived. Therefore, the side load is left, and LEFT.....no balancing side load right. This demonstrates that at least in the area of the photographic evidence, the net load is constantly left. This means a bogie that is tracking well left of the longitudinal axis of the airframe.

"Shimmy" in itself does not suggest the kind of conclusion you make, some "balanced" or normed load. There is no reason to assume the shimmy was established in consistent fashion at any time, except for the three arcs of tread deposit we see. It could have been extremely irregular.

An admission. I have not found the reference to shimmy in the Report. Therefore I do not know BEA's conclusions. I'm extrapolating on evidence I see, and read elsewhere and in the BEA work.

My assumption is that BEA rejected the possibility that a missing part contributed to the crash. If they did not, and lay some responsibility on AF, that would be a welcome coincidence?

[AlphaZuluRomeo]

Hi Lyman,

"Had no effect..." "Played no part in the crash...". "The lack of the spacer was not relevant..."

All demonstrably untrue statements.
I'm sorry, but my reaction to that is: Certainly not!
For those to be demonstrably untrue, we need far more than "just" one pic.
Do we have more? In fact yes, see below.

If in evidence (it is), and also an abnormal, we can assume there is a possibility it played a part in the tragic crash.
Yes, we could assume that, but only if the "wobble" was present for a "long" time. Was it? What elements do we have? Let's see:
- 1 picture showing what looks like the wobble, that you attributed to the missing spacer (likely, I agree); this pic also show the broken runway light; hence we know that the pic show the runway at ~2,800 meters.
- other pictures not showing the "likely wobble", or not clearly at all, taken from earlier parts of the runway;
- a rather complete description from the BEA, quoted below:
1.12.1.8 Tyre tracks
From Slab 161 level to Slab 232 level, that is between 1,807 and 2,340 m, the mark of a deflated tyre with an incomplete tread was observed.
This mark was parallel to the runway axis (at about 3.8 m) then diverged at about 2,200 metres.
When this mark disappeared at about 2,340 m, its displacement from the centreline was about 8 m. This corresponded to the right front tyre of the aircraft’s left landing gear.

Further on, some irregular tyre tracks from the left landing gear were noted up to the broken edge light (2,800 metres).
After that point, the tracks become intermittent then disappear at about 2,830 metres from the runway threshold.


OK, so, probable wobble @ 2,800m, but no wobble on the pic showing the soot on the runway. The soot on the runway, where was it? Easy:
A mark 15 m x 15 m identified as probably being kerosene was noted around line 163, 1,820 metres from the threshold. Then, traces of soot, produced by incomplete combustion of kerosene, were apparent on the runway 1,860 m onward from the origin (Slab 168). These were large and dense up to 2,300 m and then became less dense and rich in carbon up to taxiway S4, at 2,770 metres. The traces, which were on average 7 m wide, were initially centred on the damaged wheel ground mark and progressed towards the left.
On the pic showing the (dense) soot on the runway, no indication of wobble at all. Only tracks from the (already destroyed/destroying) #2 tyre.
=> No wobble @ somewhere between 1,860 m and 2,300 m.
=> Shown on the picture, and confirmed in the BEA's text (§ 1.12.1.8, quoted above)
At that time (and even considering 'only' the lower value of 1,860 m despite said §), the aircraft is already on fire, meaning the strip/tyre/fuel leak/ignition events already took place.

To be sure, let's search where other relevant items were noted relative to the beginning of the runway:
1,642 m -> the first parts found are from the water deflector, from slab 139 and onwards;
1,740 m -> the titanium strip, at slab 152;
1,740 m -> a big part of tyre (transversally cut) at same slab 152;
1,820 m -> the unburnt kerozen mark at slab 163;
1,860 m -> the first traces of soot (hence: fire);
1,950 m -> the other 'fitting' part of the transversally cut tyre at slab 180.
1,957 m -> signs of an explosion and a piece of concrete separated from the runway (my comment: that shows that the leak/fire was not due to this 'explosion' whatever it really was - EDIT it was not the tyre explosion, as noted in appendix 6 of the final report (which provides a pic): "The explosion could be explained by the forward propagation of the combustion zone").

=> this clearly shows that the fire ignited one kilometer before the only picture we may consider as conclusive of a wobble (@ 2,800 m)...
=> ... and 460 m before the first "irregular tyre tracks" were noted by the BEA (@ 2,340 m).

This is why, I think, the BEA concluded (rightly) that the lack of the spacer - even if one can discern indications it made the bogie wobble around 2,340 to 2,800m from the runway beginning - was not relevant to and played no part in the final outcome, which was sadly certain as soon as the fire broke.
QED.

Regards,
AZR.

[Lyman]

Hi AZR

Quote:
Originally Posted by Lyman
"Had no effect..." "Played no part in the crash...". "The lack of the spacer was not relevant..."

All demonstrably untrue statements.


You say then..."certainly not..."

My perverse mind sees it differently, here's why....


There is evidence the tyres were rotating in the horizontal, you agree.

That is positve proof of misalignment, a condition certified by BEA themselves as abnormal.

For the statements in the quote to be true, you offer a lack of evidence that the condition existed elsewhere. The source of your evidence of absence is blurry photography of a carbon stained runway.

Positive evidence (BEA close up photgraphy) is provided that the condition exists. A lack of evidence that it occurred elsewhere is the basis of a professional conclusion, by BEA that it had no effect on the outcome.

To a doubting reader, it seems that proof without evidence exists when the conclusion is foregone?

The "Explosion"? Have we proven without doubt it was not caused by the tyre blowout?

That would be impossible, right? Because it occurred after the fire started, and defeats the tyre as cause of fire?

hmmm......

[AlphaZuluRomeo]

There is evidence the tyres were rotating in the horizontal, you agree.
No. Possible/probable indication yes, but not evidence. I'm no more an accident investigator than Nick Thomas is, so I too am unable to draw conclusions or say "evidence" with certainty from those photographs.

For the statements in the quote to be true, you offer a lack of evidence that the condition existed elsewhere.
No. I you want to call my PoV about those photographs as "evidences", then what I see in pictures showing the runway before 2,800m is an evidence of lack (of wobble), not a lack of evidence.
And that's really different ;)

The source of your evidence of absence is blurry photography of a carbon stained runway.
The source of "my" "evidence" is no more blurry than yours, my dear chap. :)
And I didn't base my arguments on the pics (or pic) alone.

The "Explosion"? Have we proven without doubt it was not caused by the tyre blowout?

That would be impossible, right? Because it occurred after the fire started, and defeats the tyre as cause of fire?
Yes indeed.
And because parts of tyre were found before the "Explosion" place, as shown in my previous post.
And because, as shown in my edit of the previous post, there is a more sensible explanation provided (even if somehow hidden in the appendix 6, which explains I didn't remembered it.

[Lyman]

I think Twas CliveL who stipulated shimmy was shown. I think it is....

Parts of tyre can depart without causing blowout, yes? A tyre explosion is consistent with concrete delamination, such as was found.

How is it deflector parts were found before tyre parts? There was damage to bogie unrelated to tyre rupture by strip?

You have photography of the runway taken from a few meters, that shows "no wobble"? The runway pictures that show carbon deposition are aerial, long distance, no?

I acknowledge you are satisfied with the results of BEA. I think the report compelling, but it is too loose, and presumes things that are not shown, nor discussed, imho....

:ok:

[Nick Thomas]

Hi once again Lyman
I have to congratulate you for the way you keep this thread alive. Everything is quiet and then up you pop and we are all of again on the same merry go round! You tenacity is to be admired.
As I said in an earlier post and I quote "I am not an expert in this field and I therefore have to trust those who are considered to be so."
That being the case I have serious doubts about your theories as do some others posting here. In weighing evidence(if it can be called that) one has to take into account the source of that evidence. Those of us who rely on the contents of the report, do so because we know that considerable thought and effort has been put in by the experts who compiled the report. Unfortunately on a forum like this: it's not possible to know the background and experience of people like you, who post alternative theories. Until we can find a way of overcoming that stumbling block we will continue to go round and round in circles.

[Lyman]

Howdy Nick

That being the case I have serious doubts about your theories as do some others posting here. In weighing evidence (if it can be called that) one has to take into account the source of that evidence.

The wobble of the truck in horizontal is shown in the photograph, you see it differently?

BEA describes this horizontal rotation as "an abnormal"

Is that over-reliance on my opinion?

[AlphaZuluRomeo]

Hi jcjeant,

The little exercise I made just above gives me the opportunity to use its data for a follow-on about that discussion we had some pages ago:
I really have no difficulty to imagine the strip being swept along the trajectory of the aircraft, as its 200 tons rolled over it... but it seems that notion eludes some people anyway. Yes I have really difficulty to imagine the strip being swept along the trajectory (over such a large distance) of the aircraft ...
It is a concept that escapes me completely .. seems some"magic" at work there .. :)
What is the definition of "such a large distance" for you?
I'm fond of Harry Potter, but not so fond of magic regarding aviation safety.

Please, see this pic (https://docs.google.com/open?id=0B8OO8d13J2aCOTlmRTUtWjd3VE0) I made by adding things to the Annex 12 from final report.

Let's compare to the testimonies:
- Firefigther #1 said "black smoke" (tyre) around S6;
- Firefigther #2 said "black smoke" (tyre) around S5, then small fire;
- Firefigther #3 said small fire around S5, then big fire;
- Captain @ E5 (near the firefighters building) said fire begun at +/- 100m around W7.

I consider Firefigther #1 probably made a mistake between S6 & S5, because 'his' location (S6) is consistent neither with the other testimonies, neither with the material evidences.

Hence we can write:
1,500 m -> S5 TWY, the strip lay around there before Concorde rolled over it;
1,642 m -> first parts found from the water deflector, from slab 139 and onwards;
1,740 m -> the titanium strip finally lay there, at slab 152, along with a big part of tyre (transversally cut);
1,820 m -> the unburnt kerozen mark at slab 163;
1,860 m -> the first traces of soot (hence: big fire);
1,950 m -> the other 'fitting' part of the transversally cut tyre at slab 180;

=> The strip "travelled" ~240 m in the wake of Concorde and/or being for a moment stuck into the tyre.
=> Such a distance really doesn't feel 'magic' to me. Nor 'such a large distance', considering the forces involved.
=> The provided pic also shows that there is no inexplicable discrepency between the firefighters/captain testimonies and the events reported by the BEA, contrary to what some lawyers and/or TV shows would have us believe.

[Machaca]

Lyman (nee Bearfoil)

Your credibility and our sanity would be massively enhanced if after all these years and thousands of posts you could demonstrate the ability to learn and make use of the rudimentary tool for block quoting others.

[AlphaZuluRomeo]

The runway pictures that show carbon deposition are aerial, long distance, no?
Honestly? No. That's not what I see. :=

I think the report compelling, but it is too loose, and presumes things that are not shown, nor discussed, imho....
That's your opinion indeed, I acknowledge that but don't agree.
I have the advantage of being perfectly able to read French, hence I have access to the (rich) appendix 6 which was never translated to English (AFAIK).

[CliveL]

I have offered possible approaches to glean some understanding of the affect of tyre rupture, and my suggestions have been ignored.

Not ignored – maybe not agreed with or understood, but not ignored as evidenced by the number of responses you get


Likewise, an attempt to quantify would be based on data supplied from BEA, data I believe is lacking in sufficiency.

There is quite a lot of data in the BEA report that could be used in a quantitative way if one was so inclined.


It is BEA who proffered the photography, and begged the work, then did not perform it. Neglectful.

Or did not report it, which is not quite the same thing.

It was BEA who did not provide the chemical analysis of the rubber that may have proven the Titanium had been present in the tyre's carcass. In neglecting even the attempt to prove conclusively the strip was involved, they demean the discipline itself. Lazy.

But the BEA report stated


black marks were noted on the outer side of the strip and black elastomer debris was found jammed in one of the rivets. The spectra of these marks and deposits are similar to the Concorde tyre.



I don’t know what sort of chemical analysis you had in mind, but for me a spectral analysis of the material counts as a valid chemical analysis.


It was BEA that neglected elimination of material other than Titanium as the cause of tyre rupture, Cowcatcher/mount?


Are you now suggesting that the water deflectors somehow failed and got caught under the tyre? If so, how do you explain the curved failure on the tyre and the fact that the water deflectors were made of frangible material?

Was the area of the truck's mount inspected/analysed by BEA for abnormal wear? The landing gear had travelled several miles carrying two hundred tons, was the spacer's saddle worn?


Again I say yes, witnessed by their remarks...

The condition of the various pieces (shear rings, bronze bearings, seals) show that the inner shear ring had moved from its position incrementally during the last few flights. The marks indicate that the mechanism was operational although the shear ring was no longer in its position on the bronze bearings of the shock absorber and bogie.
The exact chronology of this displacement is, however, difficult to determine since the ring was not new and certainly bore marks related to its previous usage. The only marks observed on the mechanical parts correspond to movements in the vertical plane alone or to normal oscillations of the bogie.


Has anyone found an opinion on why the Captain's rudders were not planted full right? And held?


Yep! Just take a look at the figure presented in section 1.16.13.2.
By the time he got to the point you are discussing he was 2 deg off runway heading but heading back to the runway centreline (heading 270 against the runway’s 268). In addition the lateral acceleration at the cockpit had dropped to essentially zero. The aircraft was way above Vmcg even at the point of engine thrust loss, so why would he think he needed more drag producing rudder?


The report can be described in many terms. Exhaustive is not one such term.


Not many would agree with you there.

There is no reason to assume the shimmy was established in consistent fashion at any time, except for the three arcs of tread deposit we see. It could have been extremely irregular.


OK, so we can eliminate shimmy as a factor anywhere except where you found it after the aircraft left the tarmac?

An admission. I have not found the reference to shimmy in the Report. Therefore I do not know BEA's conclusions. I'm extrapolating on evidence I see, and read elsewhere and in the BEA work.


But the BEA report did contain a reference to shimmy

The Concorde landing gear manufacturer indicated that no cases of landing gear bogie shimmy had been reported. Examination of the parts revealed no such phenomenon.
Furthermore, the tyre marks left by tyre No 2 showed no signs of vibration or instability.



Therefore, the side load is left, and LEFT.....no balancing side load right. This demonstrates that at least in the area of the photographic evidence, the net load is constantly left. This means a bogie that is tracking well left of the longitudinal axis of the airframe.

Actually no, it doesn’t show any such thing, because the aircraft longitudinal axis was itself inclined to the aircraft path (sideslip).
Let me try another scenario on you.
The inclination of the bogie beam to the ‘normal’ setting would have been dependent on the balance of vertical and horizontal forces as BEA stated. Statically that would put the contact point at “12 o’clock” in the bearing housing., but again as the BEA state, the gear would be inclined to the vertical (camber). When rolling with intact tyres there would be no sideforce and the horizontal forces would be limited to the rolling friction – about 2~3% of the vertical forces. Not enough, I suggest, to move the contact point very far from 12.00.
It all changes after the tyre burst and loss of thrust. Now the horizontal force on each tyre is predominantly sideforce which would be proportional to ground reaction and tyre slip. When the aircraft started to diverge left under the action of asymmetric thrust the tyres became subject to right sideslip. When gear and tyres are intact this slip would produce forces pushing the aircraft left towards the runway edge and, because they act behind the CG, they would also make a small contribution to the yawing moment trying to return the aircraft to its original heading.
However, with the combination of a burst tyre and a sloppy bearing, the asymmetric side loads (two wheels aft, only one forward) would drive the bogie out of alignment in a sense to reduce the effective slip on the tyres to zero. In other words, if sideslip were numerically below the play in the bogie bearing the tyres would not be producing any side load at all!

So far as I can see, the aircraft was above this 2.75 deg limit for only a very short period between 97608 and 97613, which of course spans the time period at which you noticed shimmy, hence you can detect side load at that time.
This loss of sideforce would have reduced the lateral acceleration to the left (and runway edge) but would also have reduced the restoring yawing moment. But as argued above, the pilot had, and used enough rudder authority to bring the aircraft back towards the runway centreline.
Now factor in that the wing was carrying an increasing amount of lift in this period.
All of which of course begs the question as to whether this lateral displacement had any real consequences on the final outcome. My answer to that would be no, it didn’t, because when push comes to shove it was the failure to achieve a safe flying speed that mattered, and that was due to loss of engine thrust in a critical flight phase.

[Nick Thomas]

Howdy Lyman
I can accept that the horizontal rotation is “abnormal” but as I said in post 223 “Where I do agree with those who don't accept the report or parts of it, is that the many other failures brought to the fore after this sad crash should be addressed but that doesn't mean that they actually caused the crash.” Can you therefore show where in the BEA report it says that the horizontal rotation paid a significant part in the outcome of the crash? A quote out of context cannot be considered proof.
Regards Nick
p.s Lyman: My forename is actually Nixon which will forever be linked with an attempted cover up!

[Lyman]

CliveL

Thank you for a reasoned and patient response. Here are some concerns I have.

I would not have entered the thread if France had upheld the verdict. Their reasons, I assume, have to do with a lack of compelling evidence in the public domain such that a standard of proof is unmet.

I would not be here if the accident had occurred in the USA. That France considers an accident scene as a crime scene is the threshold for my interest.
As such, the BEA document is thready, and missing some important work that imo should be present in a criminal prosecution.

Evidently France considers culpability on a par with crime. That makes no sense, imo.

The major issue is the apparent speed with which the report issues opinions, yet there is no lab or field work to support.

The strip was tested for evidence of non indigenous elastomer, with success. Yet an opportunity to take a further step was ignored, I think, when they apparently rejected the opportunity to test the tyre for presence of foreign material that may have been supplied by the chemically coated Tittanium strip.

As an example, then, BEA failed to provide irrefutable evidence that the Titanium strip destroyed the tyre(#2). WHY?

Simple. If they tested and found material, the case is made. If material was not found, the strip is found only to have generic elastomer, not necessarily Concorde elastomer.

So why risk it? The mission is not compatible with the purpose of the Court. Since BEA knows criminal prosecution is a given, their standards are low, by definition.

The Shimmy? Again an example of evidence that was taken, and left 'alone'....

You see the tyre skids, and can imagine the loads put on this airframe. I think your conclusion is that the shimmy would even itself out, and provide no net effect. What about vibration? Vibration may supply no net 'load', but have a very profound effect on the pilotage.

I contend that shimmy is not normal to heavy aircraft, and can be quite destructive, yet somehow the conclusion is that since the only evidence is after the fire, it was "inconsequential". Lack of evidence through lack of attempt is not sufficient; again, the prose in the report is used to put people in prison...

I don't disagree, necessarily, but again, the possibility is demanded to be explored to lack of consequence, not assumed to be so....

I value your time, as you know, and am grateful for the opportunity to discuss this with you.

Best regards

[DozyWannabe]

I would not have entered the thread if France had upheld the verdict. Their reasons, I assume, have to do with a lack of compelling evidence in the public domain such that a standard of proof is unmet.

It was more to do with the fact that the opinion of the judge who oversaw the appeal differed from that of the judge who oversaw the original case.

As such, the BEA document is thready, and missing some important work that imo should be present in a criminal prosecution.

Have you read it thoroughly? It's a weighty document and I haven't covered all of its contents but it's about as thorough as one could hope it to be.

The BEA report is not intended to be (nor was it ever or should it be) a basis for criminal prosecution, it is simply a collection of facts and evidence (including the detail that - contrary to your earlier assertions - AF stopped using retread tyres since January 1996, BA having done the same since 1981) from which conclusions are drawn about the circumstances surrounding the accident. The document itself covers every aspect of the evidence and the accident sequence without assigning responsibility on the part of any of the parties involved.

The judges in the case had access to it simply as one piece of evidence, and the decisions regarding prosecution hinge on the representations made by the legal representatives of the involved parties - not the report.

As an example, then, BEA failed to provide irrefutable evidence that the Titanium strip destroyed the tyre(#2).

Incorrect - they (and others) used every technology available to them to assess the probability of the strip being the initiator of the destruction of the tyre, a process which was neither simple nor cheap (see report sections 1.16.5-1.16.5.4).

Their conclusion was that based on the probability of all the scenarios, the scenario whereby the strip contact was the initiator of the tyre's destruction made the most sense. They could not, and did not say any more than that.

As you correctly assert, the content of the report was not sufficient to prosecute on its own - and it was not intended to be. At the risk of repeating myself, the decision to prosecute was made by the judge based on the representations made by the legal teams of the parties concerned.

To make it as crystal-clear as I can, this and other BEA reports (like those of the AAIB) are never written with the intent of being used as prosecutorial aids. They tend to be very dry and scientific in nature (unlike those of the NTSB, which tend to be more forthright on assigning responsibility) and anyone who believes that the BEA has any say in the legal outcome of cases involving accidents is labouring under a significant misapprehension. The outcome of such cases is purely in the hands of the lawyers.

[CliveL]

Lyman,


As such, the BEA document is thready, and missing some important work that imo should be present in a criminal prosecution.But that is where it all goes wrong, because BEA are at pains to state that their work is simply to establish causes not to present evidence for a criminal prosecution. You do them an injustice, I think, to view their work as preparation of a prosecution case.

Evidently France considers culpability on a par with crime. That makes no sense, imo. In that you are at one with most of the Anglo-Saxon world brought up under common law, but it (Napoleonic law) is what they live by and we should respect that.

The major issue is the apparent speed with which the report issues opinions, yet there is no lab or field work to support.
I can't agree with you there - the report devotes fifty pages to discussion of laboratory work and testing. The long gap between the accident and issue of the report does not support your implication that it was all done in a hurry though does it?

Yet an opportunity to take a further step was ignored, I think, when they apparently rejected the opportunity to test the tyre for presence of foreign material that may have been supplied by the chemically coated Tittanium strip.
Others have commented earlier in this thread that the surface treatment of the strip might have hardness characteristics that would deter any transfer of material to the tyre. But I'm no tyre expert.

As an example, then, BEA failed to provide irrefutable evidence that the Titanium strip destroyed the tyre(#2). WHY?
Simple. If they tested and found material, the case is made. If material was not found, the strip is found only to have generic elastomer, not necessarily Concorde elastomer.
So why risk it? The mission is not compatible with the purpose of the Court. Since BEA knows criminal prosecution is a given, their standards are low, by definition.As I said earlier, the BEA mission was not to provide evidence for the judiciary. If the latter wanted additional 'proof' to cement their case they were perfectly entitled to demand it.

You see the tyre skids, and can imagine the loads put on this airframe. I think your conclusion is that the shimmy would even itself out, and provide no net effect. What about vibration? Vibration may supply no net 'load', but have a very profound effect on the pilotage.I don't like to 'imagine' loads put on any airframe. What I see is that in the time period where shimmy appears to be present the ground reaction on that gear was modest indeed, and the loads transmitted to the airframe would be correspondingly modest. So far as vibration is concerned I have already agreed (with Chris Scott) that vibration continued into the airborne part might have been a contributory factor to the decision to shut down #2 engine.

I have to say though that there is no sign of any 7 Hz variation in the lateral acceleration trace, and the normal acceleration traces show nothing higher than 1 Hz and even that dies out once airborne.

I contend that shimmy is not normal to heavy aircraft,Indeed so but as part of my researching this topic I found a presentation that implied the C17a gear might be shimmy prone. I have no more evidence but that, although the implication of the presentation was that four wheeled bogies are not usually prone to shimmy, and of course most heavy aircraft are so equipped. The C17a gear however is a three wheeled device if I have understood it correctly

Lack of evidence through lack of attempt is not sufficient; again, the prose in the report is used to put people in prison...
And again, the purpose of the BEA report is specifically NOT to put people in prison. If other parties seek to use it so that is their affair. We would all agree however that seeking to use data accumulated in accident or incident analyis is counter productive to the cause of improving aircraft safety standards :ugh:

Regards

PS Writing that whilst Dozy was posting changed the phasing, but I see that we are both saying essentially the same thing re the purpose of the BEA report.

[Lyman]

CliveL

Yes, I referred back to my post thanking you for yours and found yours missing.



Until its return, may I make a single point? From the photographic evidence at the area around the shorn runway lamp, we seem to be in agreement that horizontal movement of the wheel truck is apparent. it suggests a powerful oscillation (to me), one that may have had an effect on the early rotation, subject thus far only to speculation, and dependent perhaps on my observation of the tyre marks....

Since BEA have provided the photographic evidence to the public, and have also dismissed the possibility of horizontal oscillation gleaned from that very image, may I suggest that that constitutes the possibility of a glaring error in the report?


And one question? Do you believe the skid marks evident parallel the centerline in the BEA photo (of the carbon trail and kero stain) represent the Concorde's path?

************************************************************ **

Nick Thomas

Howdy do. There is no record to my knowledge that BEA made any representation at all of Bogie involvement in the wreck, So allow me to offer the importance of the spacer in the accident.

Let us for now say that there was no Titanium strip, and the tyre did not burst. Let us offer further that engine failure did occur, for reasons unrelated to fod, and the a/c veered leftward. This sets up horizontal movement of the bogie, and side loads on the tyres of the left MLG. Without the spacer, the bogie oscillates and vibrates. Depending on the mechanism of bogie disablement, and the clues and cues in the cockpit, might the FE have pulled #2 as he did in the actual wreck?

This was the third take off for this bird without the spacer, essentially each one a test flight, as regards landing gear. The shimmy is denied, as we see, in the report, while I maintain that it is quite possible the wreck was doubly damned, it might have crashed due the landing gear issue alone. (grantng engine failure/shut down).

[DozyWannabe]

Since BEA have provided the photographic evidence to the public, and have also dismissed the possibility of horizontal oscillation gleaned from that very image

Your language is misleading - they have not "dismissed the possibility" or anything of the sort. In fact Section 1.18.2 goes into considerable detail regarding the evidence they were presented with regarding the bogie (in spite of your claim that they made no reference to it at all). They simply consider it to be less likely to have had a significant effect than the metal strip contact, and with good reason.

If you're not inclined to take my word that the BEA report is merely a presentation of evidence (in the manner of an initial crime scene report with ballistics and forensics) - would you consider Clive's word on the matter?

[Lyman]

I have been searching CliveL's post for the quoted language from BEA that rejects any involvement of the oscillation, that there even was one. It seems to have been censored out.

Would you be able to locate it?

From the ruddering the Captain did, and the direction of the a/c well left of the runway heading, is it possible to surmise that something about the ruddering prompted Captain to give up, and accept a takeoff off runway as his best chance?

At the beginning of the veer left, to the take off point, there appears no correction right. Right rudder may have exacerbated the side load on the left bogie, and made any problem with the gear bad enough to cause him to abandon rudder as correction?

[DozyWannabe]

The (English version of the) report is here:
http://www.bea.aero/docspa/2000/f-sc000725a/pdf/f-sc000725a.pdf

Read it at your leisure, but the content regarding the bogie is in section 1.18.2 (and its subsections).

Regarding rudder input:

During the takeoff run, the aircraft would have had a tendency to deviate to the left if the left main landing gear had created abnormally high drag. However, its track was straight before the loss of thrust on engines 1 and 2 and there are no observable right rudder inputs. On the contrary, some slight actions to the left are even noticeable before V1.

In effect, the rudder inputs were *opposite* what would be expected if the missing spacer had an influence on the aircraft track prior to contact with the strip.

[Lyman]

Many thanks Doze...

aloha

Here it is...From BEA report

(from CliveL post #264)

Quote:
"The Concorde landing gear manufacturer indicated that no cases of landing gear bogie shimmy had been reported. Examination of the parts revealed no such phenomenon.

Furthermore, the tyre marks left by tyre No 2 "showed no signs of vibration or instability."

That is what is known as a discrepancy......

[CliveL]

It suggests a powerful oscillation (to me), one that may have had an effect on the early rotation, subject thus far only to speculation, and dependent perhaps on my observation of the tyre marks...By the time any evidence of oscillation is observed the aircraft was 9 seconds into a 10 second rotation, so I can't see how it could have had any effect on the earliness of the rotation. There is, as I said, no evidence of any vibration at the frequency you suggested for shimmy (7 Hz if I recall correctly) during the airborne part of the rotation through to the screen, so I conclude the oscillation had no practical effect.

Since BEA have provided the photographic evidence to the public, and have also dismissed the possibility of horizontal oscillation gleaned from that very image, may I suggest that that constitutes the possibility of a glaring error in the report?You wouldn't have found any prior remarks in any of my earlier postings (your #271) - this is the first. They didn't, so far as I can see, dismiss the possibility of horizontal oscillations during rotation - they simply did not discuss it. All their remarks on loads and shimmy seem to be related to the conditions existing prior to development of any significant sideslip. Fig 73 (English version) for example specifically shows the force balances in a possible bogie deflected condition but with the aircraft following a zero sideslip path.

I have no idea why they did not discuss the bogie behaviour in the rotation unless, like me, they came to the conclusion that it had no significant effect. This at least would be consistent with their statement that the missing spacer was not a factor. Even so they might, perhaps should have mentioned it - but that omission doesn't really change anything.

That is what is known as a discrepancy......Not if I am correct in suggesting that all their comments relate to the conditions prior to any significant deviation from straight path. NB, I have edited the original to correct the reference to pre-tyre failure conditions.

[DozyWannabe]

They didn't, so far as I can see, dismiss the possibility of horizontal oscillations during rotation - they simply did not discuss it.

Well, they mention it in the section you quoted (18.2.3.3), and then go on to discuss what effect that would have had, compare that effect to the evidence presented and conclude that it was unlikely.

I have no idea why they did not discuss the bogie behaviour in the rotation unless, like me, they came to the conclusion that it had no significant effect.

Also, at rotation, the fuel fire had been ignited and presented a significantly more clear and present threat to the safety of the aircraft than anything else. I'd say it's understandable that the report focuses on that from that point onwards.

There are a couple of paragraphs which refer to the camber of the bogie post-tyre failure compared with normal:

When the four tyres are correctly inflated, the vertical load transmitted by the bogie beam takes the axle to its upper stop on the bronze bearing of the fork on the shock strut (shock absorber). This generates a camber angle of around 2.5°. The load applied on the two outer tyres (No 1 and 5) is then increased by around 20% whilst the load applied on the two inner tyres (No 2 and 6) being diminished by the same amount.

After the burst of tyre No 2, the load that it was bearing was redistributed between the outer tyres. Consequently, a new equilibrium was generated around its axle on the outer shear ring, the camber angle returning to practically zero.

so there is evidence that the behaviour post-failure was at least studied.

[Lyman]

CliveL

When the BEA mention "tyre marks made by tyre No. 2", are they referring to only prior to tyre burst? That means there were tyre marks visible prior to burst, so I ask again, do you note the tyre marks in the photo of the kero stain, carbon trail?

Well certainly the bogie may not have been involved, but we see it was, though post burst/fire......

I am sorry to harp, if it appears so, if you say it is not relevant, I accept that, certainly.....

I understand the possibility of oscillation in the horizontal is believed to be of no consequence to the accident. But I will not admit it did not happen in the take off roll, and dismissing that portion of a serious anomaly seems counter to a full understanding of the events....
best

[DozyWannabe]

When the BEA mention "tyre marks made by tyre No. 2", are they referring to only prior to tyre burst?

Think about it logically. Post-tyre burst there would be no "tyre marks" in the usual sense of the term, as the tyre has been destroyed. From that point on it would be "debris trail" or "rubber marks".

[Lyman]

Dozy, there are marks of tyre number two up to leaving the ground.

There are marks that likely show the shape of the carcass deficit caused by the rupture/burst.

So let me ask you.

Describe the tyre marks you see prior to the kerosene stain in the long photo. the ones that continue along the centerline.

I have some follow up questions.

[CliveL]

so there is evidence that the behaviour post-failure was at least studied.

Yes, but not in the phase where there was appreciable aircraft sideslip

[CliveL]

But I will not admit it did not happen in the take off roll,

OK, if that is your view then fine; but I see no evidence or know of any physical explanation that would support your position.

[DozyWannabe]

Yes, but not in the phase where there was appreciable aircraft sideslip

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

[Lyman]

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.

[CliveL]

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

[Feathers McGraw]

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

[Nick Thomas]

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.

[Lyman]

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?

[Nick Thomas]

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.

[CliveL]

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.

[Lyman]

Sorry.....

Was Continental Responsible For the Concorde Crash? « Heritage Concorde (http://heritageconcorde.com/facts/was-continental-responsible-for-the-concorde-crash)



the "other runway pic."

rgds.

[DozyWannabe]

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.]

[CliveL]

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.

[AlphaZuluRomeo]

Sorry.....
Was Continental Responsible For the Concorde Crash? « Heritage Concorde (http://heritageconcorde.com/facts/was-continental-responsible-for-the-concorde-crash)

the "other runway pic."
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 runway pictures that show carbon deposition are aerial, long distance, no?Honestly? No. That's not what I see. :=
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 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.
... 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.




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

[jcjeant]

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

suspension_CDN_concorde.WMV - YouTube

[DozyWannabe]

@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.

[Lyman]

Hi Doze.

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

[DozyWannabe]

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.

[jcjeant]

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

[DozyWannabe]

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.

[jcjeant]

Hi,

DozyWanabee
The note was confidential, the fix made as a result of it was not
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)

[DozyWannabe]

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.

[jcjeant]

just the way things worked in the '70s I suspectAnd this is how it worked in 2010 ...

2010 procès Concorde
Question (Me Rappaport - avocat)
A quel moment a été envisagé le risque incendie à la suite d’un éclatement de pneu ?
Answer (Mr Arslanian - directeur BEA)
A l’étude des évènements, nous n’avons pas relevé de risque incendie

Note confidentielle de Mr Guillevic (BEA) 1979
Quelque soient les résultats des investigations en cour,l'incident de Washington et les incidents antérieurs mettent en lumière la gravité des conséquences possibles d'un éclatement de pneu:
risque d'incendie par écoulement hydraulique ou de carburant sur des éléments du train surchauffés ou en combustion ,avarie grave de moteur,impossibilité de relevage du train d'atterrissage et limitation des possibilités de freinage et évidement combinaison de deux ou plusieurs de ces effet possibles


2010 Concorde trial
Question (Me Rappaport-lawyer)
At what time was considered the fire risk following a burst tire?
Answer (Mr Arslanian BEA director)
After study of the events , we found no fire risk

Confidential note Mr Guillevic (BEA) 1979
Whatever the results of the investigation in progess, the Washington incident and previous incidents highlight the seriousness of the possible consequences of a burst tire:
fire hazard from hydraulic flow or fuel elements of the gear overheated or burning, severe damage to the engine, the impossibility of lifting gear and limiting the braking ability , combination of two or more of these possible effect

[DozyWannabe]

It's possible M. Arslanian never saw the 1979 memo prior to the 2000 accident, it being 21 years old by then. More importantly the 1979 memo is clearly referring to an investigation in progress (presumably by the NTSB) that was later completed and published resulting in modifications that were thought to minimise or remedy the risks from a burst tyre. He's well within his rights to say what he's saying because the modifications to equipment and procedures over the intervening years were expected to have all but eliminated the risk of fire from a tyre burst.

I should have pointed out in my previous post that all Concorde tyre debris-related incidents between 1979 and early 2000 resulted in the same type of external piercing damage which was not considered to present a significant fire hazard. I reiterate - the one and only time the damage caused a burst from inside and a significant fuel leak was the F-BTSC accident.

To borrow a phrase from Bill Clinton, "There's no 'there' there".

[Lyman]

Asked to give her opinion of Oakland, California, Gertrude Stein famously said : "There's no there there..."

Asked a question by Monica Lewinsky, Bill Clinton famously said: "There it is.."

Dozy, you know as much about AF tyres as you do Americana...

.....not very much

[DozyWannabe]

Correction on Clinton accepted (although the phrase was used by the presiding judge over the "Judicial Watch" lawsuit against the Clinton Administration). If you'd like to point out where I'm wrong on the other matters, I'm happy to hear it. Supporting evidence preferred.

[Lyman]

Air France ceased reporting tyre incidents for some years between Dulles and Gonesse. My search function does not work. Show us your objectivity and assist me. It is in this thread.

For truth.....

[DozyWannabe]

Once and once only will I be your monkey (no offence, but while I'm all for objectivity and truth I'm still suspicious of being played for a fool).

Using both the search function and a visual check of all occurrences of the word "tyre" or "tire" (for our transatlantic cousins) I can find no post referring to AF not reporting tyre failures. Outside of the fact that it would be extremely difficult to do so because such incidents are required to be reported by regulations, I have to conclude that if such a post ever existed it was retracted, or it was misread.

The closest thing I can find is AZR's post early in the thread which states his opinion:

Indeed, I think AF/French authorities in general took "too lightly" some issues with the plane (namely: tyres, and the Michelin NZG fitted for the return to flight were an excellent thing).

But that's a long way from saying they didn't report tyre burst issues, which would be a serious breach of protocol.

[CliveL]

Confidential note Mr Guillevic (BEA) 1979
Whatever the results of the investigation in progess, the Washington incident and previous incidents highlight the seriousness of the possible consequences of a burst tire:
fire hazard from hydraulic flow or fuel elements of the gear overheated or burning, severe damage to the engine, the impossibility of lifting gear and limiting the braking ability , combination of two or more of these possible effect As Dozy pointed out, this note was written during the investigation of the Washington incident and as such correctly points out the possible consequences that should be considered in that investigation.
This should be read in conjunction with section 1.16.4.2 of the BEA report which describes the results of that investigation and the modifications that were applied as a result.

[AlphaZuluRomeo]

jcjeant,

We have established facts, here.

1/ The BEA wrote a confidential memo.

2/ Lessons from '79 did not prevent Gonesse.

You're linking those two facts into a theory that makes you (almost?) accusing people back in '79 to have said: "let it crash, it doesn't matter". :ooh:
Really? :ugh:
Can't you imagine other theories? Or do you choose not to mention them because they do not correspond to a certain (preconceived?) idea you might have?


Let's try again, shall we? ;)

1/ The BEA wrote a confidential memo.
Yes. Question is: why?
Perhaps at the time it was written, it was simply a work document, classified as confidential "by default" as is usual in most organizations: Only approved communications are made public. And before that, documents relative to an on-going inquiry are not meant to be public. Do we have the date of that memo? Clive answered the question while I was writing this. We now have an answer]
« O tempora, o mores ». This was 1979, 30+ years ago. The cold war. No Internet, no Web (ARPANET was just live, for US military only). Far less transparency then than now exists.
And there was political pressure about Concorde at the time: Let's not forget that flight restrictions in NY / USA were just lifted (IIRC) after a long and painful "battle". Bad publicity would have jeopardized the future operation of the aircraft (which had only recently entered service), giving "ammunition" to his opponents.


2/ Lessons from '79 did not prevent Gonesse.
Indeed. But this undeniable fact has too often been distorted into "nothing was done" or something like that. This distortion is wrong: Fixes were implemented after Washington'79 and other tyres events, before the 2000 crash, and this was already stated numerous times in this very thread (among others).
Those fixes were aimed at correcting/solving the issue with the tyres. They didn't succeed (enough). But we can only say that with hindsight.

Washington'79 and Gonesse were different events regarding the importance of the fuel leak (hence the importance and destroying capabilities of the consecutive fire). And the difference is not a little one, see my #59 (http://www.pprune.org/rumours-news/501620-concorde-crash-continental-airlines-cleared-france-court-3.html#post7553552).

Conclusion:
I have no difficulty imagining the political leaders of the time (IIRC the issue had risen to the presidency) decide to remain discreet and try to control the information made ​​public.
With our current mindset, we can find it "weird" or even suspect. But when we remember the time and conditions ... it does not seem so suspect anymore, IMO. Even if we wouldn't accept such things anymore: the world has changed!

But the fact that discretion was required does not automatically means that the people advocating for that discretion were refusing to fix the issue at hand. :=

I cannot imagine, OTOH, that people (from BEA, DGAC, AF, French gov...) were convinced that there still was a great risk of accident after the fixes were implemented. I cannot imagine they have deliberately limited the range of the fixes, that would have meant they didn't care if a Concorde took fire and crashed later.

[jcjeant]

AZR
I cannot imagine, OTOH, that people (from BEA, DGAC, AF, French gov...) were convinced that there still was a great risk of accident after the fixes were implementedHow much "tires incidents" after Washington accident and the subsequent fixes ?
Is the fixes were the solution to the risks confidentially described in 1979 ?

Fixes were implemented after Washington'79 and other tyres events, before the 2000 crash, and this was already stated numerous times in this very thread (among others).Nobody disputes the fact that fixes were made after 1979
The fact is, whether these were the good fixes to the potential risks
Is that all risks have been taken into account to determine the solutions to bring ?
Or is that some risks have been set aside by the use of comforting statistics ?

[CliveL]

The fact is, whether these were the good fixes to the potential risks
Is that all risks have been taken into account to determine the solutions to bring ?
Or is that some risks have been set aside by the use of comforting statistics ? With hindsight we know that the fixes applied were not enough to protect against fuel tank failure arising from a hydraulic shock inside the tank. But bearing in mind that this failure mechanism was completely unknown at that time (at least in the civil side of the industry) we can judge whether the fixes applied were consistent with giving adequate protection against the 1979 state of the art from section1.16.4.2 of the BEA report.


The relevant parts of that section state:


Risk of fire. Based on the data about the leak in the accident, the study concluded that the risk of fire was limited, considering:
o that the size of the penetrations and the rate of flow of the leak are sufficiently low;
o that ignition cannot be caused by rubber or metal debris penetrating the tank;
o that the fuel leaks from tanks 6 and 7 follow the flow under the wing and remain generally parallel to the aircraft axis without meeting areas of separation and thus dissipate via the wing trailing edge .The secondary nozzle’s temperature is too low to ignite the fuel;
o that fuel from leaks in tanks 5 and 8 may accumulate in the landing gear well. Only the electrical circuits in this compartment constitute a possible source of ignition;
o that ignition of the fuel on contact with hot brakes would not definitely occur, bearing in mind the average temperature reached by the brakes;
o that in case of penetration of the tanks forward of the air intakes, leaks would be limited (due to the limited size of the debris taken into consideration) and could only enter the engine at a very low speed (after landing) and at a high thrust level

Most of the solutions then proposed were in fact put into effect and were the subject of Airworthiness Directives:
• AD of 14/01/8, applied from 21/01/81, calling for the installation of a system for detection of main landing gear tyre under-inflation. An improved version of this system was then applied by AD on May 15 1982,
• AD of 14/01/81, applied on 21/01/81, calling for improvements in protection in the normal braking hydraulic system,
• AD of 5/05/82, applied on 15/05/82, defining an inspection procedure for the main landing gear tyres and wheels before each takeoff,
• AD of 5/05/82, applied on 15/05/82, calling for the installation of new reinforced wheels in order to limit damage in case of contact with the ground and for new reinforced tyres capable of bearing twice the normal load (the regulations require one and a half times).


As a result of studies carried out on the risks of damage from pieces of tyre and on trials performed at the CEAT in 1980 to justify the integrity of the structure in case of direct penetration, it was concluded that it was not necessary to install protection for the underside of the wings.


1.16.4.2.2 Other Events
All of the tank penetrations that occurred after the Washington event involved aircraft operated by British Airways. It should be noted that after the modifications carried out after this event, tank penetrations following a tyre burst were caused only by secondary debris.
In most cases, this debris came from the destruction of equipment located in the landing gear area, probably dislodged by pieces of damaged tyre. The parts in question include the water deflector and the gear door latch.
Everyone will have their own view on this I'm sure - I'm staying out of it !

[roulishollandais]

Not only for Concorde had the tyres' explosion possible various issues. DGAC was already in the glue of absolute SOPs theory to limit captain's autority and destroy SNPL and other French Pilots Unions. DGAC was not able to let the Captain reject T/O after V1 in case of tyre explosion. LFPG had the best firemen in France, would they had to extinguish the plane fire on the RWY 08 and not in Gonesse they could save lifes.:}

[AlphaZuluRomeo]

I'm afraid I fail to see your point, RH... :confused:

I'm convinced things should (must) change @ DGAC (perhaps change is already on the way, at last I hope so) but that's not the point.

DGAC was not able to let the Captain reject T/O after V1 in case of tyre explosion.
I was under the impression that V1 meant just that: no more reject T/O.
Why would DGAC (alone?) change that? I'm not sure that advocating for an exception (a derogation, once again?) is such a good idea.

LFPG had the best firemen in France, would they had to extinguish the plane fire on the RWY 08 and not in Gonesse they could save lifes.
I can't comment on firemen quality. But the BEA calculated the speed at which Concorde would have overrun if the T/O had been rejected (two hypothesis, depending on when the T/O reject would have been initiated).
The figures were impressive (74 kt or 115 kt) (the entire § is quoted in my post #138 (http://www.pprune.org/rumours-news/501620-concorde-crash-continental-airlines-cleared-france-court-7.html#post7570979)). And there is the cargo zone 1,200m after the threshold, with parkings & buildings. I understand from the report that Concorde overruning would not have created a situation with better chances of survival. The exact wording is: These figures show that an aborted takeoff would have led to a runway excursion at such a speed that, taking into account the fire, the result would probably have been catastrophic for the aircraft and its occupants.
What makes you suppose otherwise?

[jcjeant]

One of their main lawyer just die
Google*Traduction (http://translate.google.be/translate?sl=fr&tl=en&js=n&prev=_t&hl=fr&ie=UTF-8&eotf=1&u=http%3A%2F%2Fwww.ouest-france.fr%2Factu%2FactuDet_-La-disparition-de-l-avocat-Olivier-Metzner-retrouve-mort-en-Bretagne_55257-2174178_actu.Htm)
Note that UK = Brittany .... :rolleyes:
La disparition de l (http://www.ouest-france.fr/actu/actuDet_-La-disparition-de-l-avocat-Olivier-Metzner-retrouve-mort-en-Bretagne_55257-2174178_actu.Htm)

[blind pew]

Jc - knew to much about Christiane?