Concorde Paris crash, questions, facts, opinions

[jcjeant]

Hi,

I followed closely all this Concorde tragic event from the beginning (as lambda citizen) and also read all the reports of BEA and the reports from the British inquiry side.
Also read the report of the judicial process.
The case is very simple ...
It's the metal (titan) part loss by Continental aircraft who launch the events of the crash or it is not.
If you follow the BEA report .. the conclusion is that is the metal part involved ...
But in the judicial process .. the experts were not able to explain the exact processus who followed after the collision with the metal part ...they were not able to remake it in laboratories ... they have just some toughts.
Mr Arslanian and so the BEA (the BEA boss at time) when questionning about the other thesis (fire before collision with part) discarded (why? no reasons unless some as explained in a post above) the reports of the firesquad crew and also the report of the crew of the plane waiting aside (president Chirac aboard)
One can ask .. what is the more embarassing option for the frenchs (and this is a lot of french parties involved) .. ?
Fire before or after metal part collision ?

[ChristiaanJ]

Originally Posted by jcjeant

Fire before or after metal part collision ?

If, as you say, you've read the full BEA report, you should have seen, that the start of the soot marks on the runway (from the 'fuel-rich' fire), start at about the same location as the metal strip, the tyre fragments, and the metal part from the wing tank were found.

Postulating a wheel or brake fire (by itself an exceedingly rare occurrence) only a few seconds before the aircraft runs over a metal strip, ripping the tyre apart and starting a big fuel leak, is really pushing coincidence too far.
Such an improbable scenario could only have been invented by lawyers clutching at straws.

The unreliability of eyewitness report has already been discussed in earlier posts.

CJ

[jcjeant]

Hi,

The unreliability of eyewitness report has already been discussed in earlier posts.

If the justice follow this idea ... it will not be necessary in any judicial process to call eyewitness
It's of course unreasonable...
Unreliability of eyewitness dogma can't be a argument for discard them.
It can't not be common rule cause in the past for any cases some were unreliables
It's also know .. many eyewitness were very reliables.
And more .. in this case it's not one eyewitness .. but many and located in different aeras with differents point of view...
Are those eyewitness considered to have a collective hallucination ?
AFAIK ... the Concorde was a exeptionnal plane but not a UFO !
About the soot deposit and other material found ..etc .. those can been released well after the fire was initiated
Seem's to me .. something was discarded for comply with only one possibility ... the collision with the Continental part.
I'm convinced ... after the verdict in December and is expected ... many people will not be satisfied (for good or bad reasons) and remain convinced that the investigation and the judicial process were not fair or will not have been at the bottom of things.
Sure .. all will understand why the BEA emphasize on the metal strip and Continental emphasize on the witnesses reports
Also .. as there are no corrections to make to the plane (it will not fly anymore) the investigators and regulation bodies don't worry about the technical consequences that could have their findings

PS
We can not rely on the improbability of debris or foreign objects on a runway.
This is not surprising (and that is why the tracks are regularly inspected)
So an object or debris (not a Caterpillar) should not pose a threat as it involves the destruction of an airplane .. if it is well designed
The tires on the Concorde (and incidentally tanks) have been the source of many problems before Gonesse and have relied in many incidents.
Apparently .. they are also involved in the fatal accident (with or without foreign object)

[lomapaseo]

Eye witness acconts are just a part of the fact gathering process as well as soot and debris on the runway, etc. etc.

It is the linking of these facts that becomes the basis of a causal chain. If the hypothesis being tested to propose a complete link of the causes of an accident is challenged by any fact, then that fact is examined in detail for its validity (is it a could be? or scientifically accepted). Is it verrifieable by more than one means?. Just because 2 or 3 people say there was a fire earlier based on observation doesn't mean they were seeing the same evidence. when examined in detail they are often not sure what they saw and precisely when, but vaguely remember their conclusions.

On the other hand the exact location of a mark on the runway is verifiable by photos and GPS as are metalurgical findings. So often "some" eye witness reports are not verifiable by other means and are ulimately discarded from the analysis section of the accident investigation.

[jcjeant]

Hi,

Just because 2 or 3 people say there was a fire earlier based on observation doesn't mean they were seeing the same evidence. when examined in detail they are often not sure what they saw and precisely when, but vaguely remember their conclusions.

You right ...
The important part of a witness report is his first (hot) report .. not influenced by other news or events.
It's common to have from a same witness a different report after sometime .. cause he know others things linked to the event (by the press .. investigators .. police etc ..)
He is influenced by all this and can begin to have doubts and his view can change for many reasons (even a feeling of culpability)
It's a well know phenomena.
So it's the first report (immediately after the event) who is the more credible.

[Agaricus bisporus]

It is so very noticeable how posters on this forum adapt the "rules" shamelessly to suit their purpose.

In the normal, run-of-the-mill accidents we read of here on PRUNE witnesses report all sorts of phenomena that they are willing to swear to and are instantly vilified and ridiculed by all and sundry who weren't there yet take the vehement view that eyewitnesses are inherently unreliable, and those with sociological and psychological backgrounds add their more scholarly views that back up this inherent reliability. The views of the witnesses are usually scotched - and I have to say almost always correctly, as subsequent investigation proves. Studies show that people are reasonably good at recalling discrete events but quite poor at reporting those events in the correct order; yet superb at reporting events however unfeasible and regardless of whether seen/heard or not when in a manner that they think credibly fits the scenario.

Yet when a conspiracy theorey is involved (as is so clearly the case with Concorde) then any doubt in the veracity of those self-same, well understood and accepted as unreliable witnesses is howled down and ridiculed - specifically by those wishing to back up the statistically/logically/intellectually unlikely or personally distasteful course of events they are trying to promote in direct contradiction to all the evidence.

Just look at the Mull of Kintyre Chinook CFIT accident to see how bizarre and self-propagating this effect can become.

[ATC Watcher]

Very interesting philosophical remarks Agaricus bisporus.

Another wild hypothesis : and if both were right ? like a fuel leak (yet undedected by the on board sensors ?) ignited by the PC during the t/o roll and then hitting the metal strip that then caused the tire blow and subsequent tank failure and massive fire distructing the structure ?
All your witnesses and evidence would then be correct would 'it ?

I am not saying that this is what hapenned,( not even sure it is possible ) I am just fitting a scenario to satisfy most (questionable /contradictive/ not sustained by material evidence ,etc) witness reports. This is not scientific but it is what police do all the time.

There are maybe more such scenari.

[robert f jones]

ChristianJ

My point, you may have missed, is you NEVER shut down an engine on fire below 1000 ft agl if it is producing thrust. No twice thinking, no time, just rule of life.
bjornhall - your posts :
"An aircraft was overweight...not a factor". Probably not on all engines (illegal of course) but significent with an engine out.
"out of trim ?" BEA report, albeit marginally.
"taking off downwind". After receiving the ATC wind check, no comment on the CVR, read the BEA report. In my opinion the 3rd factor, and probably most significent in the accident. Also probably outside Flight Manual limits and therefore illegal.
Back to Christian. Are you saying that after 2 mins the aircraft crashed due to structural failure from fire damage ? My reading of the report was that they had to reduce power on the two good engines to reduce bank.
The aircraft stalled, hence no forward motion. Small point, but had it flown a little further it would probably not killed people on the ground.
It will be interesting to hear the result of the Judicial review.

[Brit312]

My point, you may have missed, is you NEVER shut down an engine on fire below 1000 ft agl if it is producing thrust. No twice thinking, no time, just rule of life

Not wanting to get into this arguement,but I have just looked up the actual
published proceedure for dealing with an engine failure after V1 on Concorde

Maintain V2 or achieved speed on intial climb

Once the aircarft is established in intial climb and the gear is up
the F/E will repeat the failure call and identify the engine call. If I
remember corrrectly this would normally happen around 400ft agl

The flying pilot will call for the fire drill checklist and the memory items will be
commenced. [this entailed shuting the engine down]

At 600 ft agl adjust pitch attitude to accelerate to V2 +40 before
commencing climb again

My reading of the report was that they had to reduce power on the two good engines to reduce bank.

If you look at the following flight recorder traces you will see that Nos 3 and 4 engines were operating at full power until the very last few seconds of the flight when the pilots sadly lost control the aircraft

CONCORDE SST : Accident Report

I am sure none of us want to score points here, so hope this will help clarify things a bit

[ChristiaanJ]

robert f jones,
Too much "conspiracy stuff", not enough hard facts, and IMHO, not enough logical thinking from your part.

Originally Posted by robert f jones

My point, you may have missed, is you NEVER shut down an engine on fire below 1000 ft agl if it is producing thrust. No twice thinking, no time, just rule of life.

You obviously missed MY point... I already said I agreed. But not shutting down the engine would not have made the slightest difference to the final outcome.

bjornhall - your posts :
"An aircraft was overweight...not a factor". Probably not on all engines (illegal of course) but significent with an engine out.
"out of trim ?" BEA report, albeit marginally.
"taking off downwind". After receiving the ATC wind check, no comment on the CVR, read the BEA report. In my opinion the 3rd factor, and probably most significent in the accident. Also probably outside Flight Manual limits and therefore illegal.

All of these factors influenced the exact final location where the aircraft crashed.... they were not at the origin of the crash... again, as I said already.

Back to Christian. Are you saying that after 2 mins the aircraft crashed due to structural failure from fire damage ? My reading of the report was that they had to reduce power on the two good engines to reduce bank.

Read again....
For about half a dozen reasons, once the fire started, the aircraft rapidly became incontrollable.

The aircraft stalled, hence no forward motion. Small point, but had it flown a little further it would probably not killed people on the ground.

Quite, and that's now been stated for dozens of times.
If one of all those secondary factors, that everybody loves to quote, had not occured, the aircraft would probably not have crashed on the hotel.
So where would it have crashed? Maybe on the A1 motorway? On the turn towards Le Bourget? There are people living there too, you know..... At Le Bourget? Nice choice of buildings and hangars there too.... unlikely that by that time they still could have aimed for the runway.

Quite frankly, Roger. Concentrate on what happened, not on the endless "what ifs" that are not really relevant.

It will be interesting to hear the result of the Judicial review.

Quite what do you expect from that? Reality?

CJ

[bjornhall]

There is a little too much misinformation on this thread by now... Let's not agree on things that are not factual. This is a rather straightforward event, and there is no need to confuse matters with misconceptions and false "facts".

Aircraft overweight a factor with an engine out? No. 0.5 % makes no difference, and that is not me saying that but the investigators who looked into that fact.

Out of trim? Where does the report say that? It talks about how much fuel would have to be pumped out of tank 11 during taxi before takeoff to be in trim, but that was not unusual, and where does it say that was not done? If you are talking about the 54.3 % CG indication observed on the pilots' CG indicator after the crash then that is also not significant; it is the load sheet values that matter as long as the CG indication is not off by more than 0.3 %. Also, 0.3% is not a large shift on that gauge; who can tell it did not move at all during the impact?

Again, we do not know if it took off downwind; some indications say it did, some say it didn't, but it is perhaps more likely it had a few knots tailwind. It was definitely within the flight manual limitation. I still do not see how it would make a difference; I suppose you are suggesting it would have been moving faster when the tyre failed and thus been able to climb better? But how would that allow it to land before the fire brought it down? It would not. If indeed it took off with the full 8 kt tailwind reported by the tower it would have been another couple tons overweight due to the tyre speed limitation, but since it rotated before Vr it was off the ground well before that limitation.

The aircraft most decidedly did not stall! Control was lost due to the effects of the fire, due to the combination of the number one engine surging and flight control damage. We know that by comparing aircraft behavior with control inputs from the FDR. Yes, they pulled back power on the good engines to reduce bank, in an effort to regain control. The bank was a result of the flight controls not being able to counteract the impact of two failed engines on one side, although the aircraft was well over VMCA-2.

And finally, according the the report there as ambiguity regarding when the fire drill should be executed; some generic Air France manual said after being established in the climb (citing some altitude figure if I remember correctly), whereas the Air France's Concorde manual said it should be done immediately (do not remember the exact names of the two manuals, look it up if it is important). The captain and the flight engineer apparently agreed on when the drill was to be executed, since the captain called for the drill at the same time when the flight engineer stated that engine 2 should be shut down (I can not tell from the translated transcript whether that was something the FE suggested should be done, said he was going to do or said he was already doing). Procedures are not to be changed during their execution in an actual emergency, Robert's "rule of life" notwithstanding.

Now, in case there is anything left to be said about this accident... Perhaps we could discuss what happened and why, rather than dwelling on things that never happened and facts that aren't true?

[lomapaseo]

There is a little too much misinformation on this thread by now... Let's not agree on things that are not factual. This is a rather straightforward event, and there is no need to confuse matters with misconceptions and false "facts".

Sounds great to read, but let's be careful about distinguishig accepted facts from analysis in a report.

In my view anything to do with the actual performance of the aircraft is "analysis" based on facts (e.g. DFDR, radar tracks, etc.). Many other conclusions in the report are also not facts but analysis.

It is not uncommon for the parties to an investigation to accept most facts but disagree on the conclusions based on analysis of these facts.

[robert f jones]

ChristiaanJ

Now there is an interesting response, "what did I expect" from the enquiry ?

On behalf of the defendants, Continental and others, justice of course. After nine years they deserve it.

Can you convince bjornhall that the aircraft stalled, look at the area of the wreckage, not much larger that the wingspan of the concorde.

[bjornhall]

Robert, that is honestly a rather interesting question you're bringing up.

What is the stall speed of the Concorde?

Some Nasa engineer in a Usenet forum some 10 years ago told me it was in the order of 60 kts, a totally theoretical figure of course... Not sure if it is accurate or not.

The point is that the aerodynamics of the Concorde is different, it does other bad things at low enough speeds, but it hardly stalls as far as I understand.

It is a bit of a technicality... The point is that it did not depart controlled flight as a result of a stall, which would have been a reasonable conclusion for a conventional aircraft given the final maneuvers and the wreckage distribution.

[DozyWannabe]

Originally Posted by robert f jones

Can you convince bjornhall that the aircraft stalled, look at the area of the wreckage, not much larger that the wingspan of the concorde.

Well no, the evidence suggests that it reared up almost to the vertical and fell tail-first, hence the small debris field. But it is not necessarily indicative of stall - the rapid degradation of the flight controls due to the fire could have just as easily caused departure from controlled flight in that way.

[ChristiaanJ]

Of course a Concorde doesn't stall in the conventional sense.... I thought that was sufficiently known.

As to what happened in the last half-minute... maybe somebody could find the link, and post it, to the "computer animation" ? (Which by the way is not fiction, but directly derived from the FDR record.)

I doubt it'll convince people like Robert et al, but it would be usueful to have it at hand in this thread.

CJ

[ATC Watcher]

Computer animation Gonesse accident

Here is one , not sure it is the one you mean though..
Vidicom : Movie Frameset

[The late XV105]

Video animation

Video animation of the flight

(We posted together it seems!)

[ChristiaanJ]

ATC Watcher and XV105,
Thanks!
It's a small and speeded-up version of the original, but that is the one I meant.

And calling that a "stall" is of course irrelevant.

CJ

[Misterredmist]

All interesting stuff and of course a tragic accident , but such an iconic aircraft will always attract such ongoing debate.

One thing I may have been interested in if I was a CO lawyer, would be something I read in another Concorde thread on this site, and I have no reason to doubt the validity of the claim, as the person who placed the information seems to know his onions on the operation of Concorde's engines.

IIRC he mentioned that Olympus engine 4 was kept well below max thrust until 80kt was reached, meaning the PF would have to adjust for the inclination of the greater thrust on the left hand side of the aircraft steering the nose towards the right.

It seems a little strange that the aircraft seems to have actually headed to the left of the runway very early according to some reports....

Just a thought from a humble SLF