Concorde Paris crash, questions, facts, opinions

[ChristiaanJ]

We already have another Tech Log thread running on the subject of "Concorde Questions", relating Concorde facts, questions, stories, anecdotes, etc.

Rather than 'dilute' that thread with the inevitable discussions and opinions on the background of the Concorde Paris crash, it seemed appropriate to start a separate thread on the subject.

The basic facts are clear enough.....
On July 25th, 2000, during take-off, Air France Concorde F-BTSC ran over a titanium strip that had dropped off a Continental DC-10 a few minutes before.
This did not just cause a tyre blowout, but totally ripped the tyre apart, throwing large enough fragments against the underside of the wing to cause a major fuel leak.
The leaking fuel caught fire, resulting (for various reasons) in a loss of power on the #1 and #2 engines.
The aircraft could not maintain height and crashed about 2 min later.
In the accident 113 people died, of which four on the ground.

CJ

[rudderrudderrat]

Hi ChristiaanJ,

Really enjoyed reading the Concorde thread.

I've seen a TV "reconstruction" about the Paris crash which suggests a "spacer" was missing from one of the bogies which made steering in a straight line with an engine failure impossible. The skid marks show the aircraft drifted very close the runway edge, and it's implied that the aircraft was forced to rotate and get airborne rather than stop and collide with another aircraft at an intersection.

Do you have any more information whether this is fact or fantasy?

[ChristiaanJ]

...a TV "reconstruction" about the Paris crash which suggests a "spacer" was missing from one of the bogies which made steering in a straight line with an engine failure impossible.....
....Do you have any more information whether this is fact or fantasy?No, I don't...
The missing spacer is a fact.
Whether it made the slightest difference, with what amounted to a dragging left main gear after the tyre blowout and a double engine failure at takeoff, is something I don't know.

CJ

[archae86]

Air France Concorde F-BTSC ran over a titanium strip that had dropped off a Continental DC-10 a few minutes before.I believe I have read that lawyers for Continental or for the maintenance guys have argued the case that evidence shows the fire to have started before the location of the strip.

After typing that I checked around, and found that stories put out by the BBC, ABC, and other news organizations report that claim being made at the opening of the February 2010 trial.

Can anyone who has seen the evidence on that point pro and con discuss their own assessment? I have not.

Strip or no strip, the tires then in use failed often enough, and the aircraft was vulnerable enough to that failure, that a serious accident would seem unduly likely to have happened within a few years unless at least one serious corrective measure had been taken (either tires much less likely to fail this way, or an aircraft with considerably reduced vulnerability).

[EXWOK]

No Concorde tank was ever penetrated by a tyre. Really.

Early events were cause by WHEEL failures, hence the redesign of the wheel ('blue' wheels).

A piece of 'cow catcher' (water deflector) penetrated a tank following a tyre burst, this led to the modification of the 'cowcatcher'.

So this event was unique. The tank was not penetrated but was blown out from inside some distance from the point of impact.

So....not necessarily an event definitely 'likely to occur in the next few years'.

Reasons for the blowing out?? Manifold - and subject to some conjecture, but it was not possible to replicate the event in testing when the fuel system was configured as per flight manual.

[BOAC]

Holes in 'French' cheese?

[HEATHROW DIRECTOR]

Any comments about the aeroplane taking off downwind?

[411A]

Any comments about the aeroplane taking off downwind?
And...overweight (mass for our Euroland friends). :}

[RenegadeMan]

I'm sure I speak for all Concorde fans when I report that seeing the news on TV about the crash that day was one of the saddest moments in avaiation history (only outdone by the 9/11 events the next year)

Long live that magnificent white bird. None of us will ever forget the sheer majesty and marvel that was Concorde...

[bizdev]

On the other - truly brilliant - Concorde thread, there was a comment made which indicated to me that those contributing to the thread, i.e. those that had either flown or maintained Concorde, had a different theory or opinion to that of the official crash report? Or have I mis-interpreted?

[jcjeant]

Hi,

Many answers at the questions are in the record of the trial (by the investigation experts and also the people who conceived the Concorde)
This is the complete record of the trial as reported by the passengers association (FENVAC) who followed the trial
Warning :
This is a pdf in french language
PROCES-CONCORDE-RAPPORT_FENVAC.zip - 4shared.com - online file sharing and storage - download (http://www.4shared.com/file/R36bONc1/PROCES-CONCORDE-RAPPORT_FENVAC.html)

[lomapaseo]

EXWOK


No Concorde tank was ever penetrated by a tyre. Really.

Early events were cause by WHEEL failures, hence the redesign of the wheel ('blue' wheels).

A piece of 'cow catcher' (water deflector) penetrated a tank following a tyre burst, this led to the modification of the 'cowcatcher'.

So this event was unique. The tank was not penetrated but was blown out from inside some distance from the point of impact.

So....not necessarily an event definitely 'likely to occur in the next few years'.

Reasons for the blowing out?? Manifold - and subject to some conjecture, but it was not possible to replicate the event in testing when the fuel system was configured as per flight manual.


Just trying to clarify my understanding of what you have said

Putting aside the previous (to the crash) incidents what, where and how did the fuel tank penetration in the crash occur?

It was my understanding that the rubber tread from the tyre struck the tank setting up a hydraulic shockwave (full tank) which reverberated back and progressed a minute fracture in the aluminum to a square foot blown out hole. This rather large piece of the tank wall was recovered from the runway.

If you have something different from my understanding would you describe it?

[d747]

Hi,
As person who follows PPRUNE but does not post often I have a question regarding the crash.

On one of the TV programmes I have viewed about the crash it was stated that the fuel poured out of the tank and was ignited by a damaged electrical cable that was creating sparks. I have one issue with this, watching another programme (air crash investigation) about TWA800 a demonstration was made that proved jet fuel did not ignite if a match (bit more than a spark) was dropped into it. If the fuel was heated to 53 degrees and a match was dropped in the fuel ignited.
My point being what did ignite the fuel that was leaking from the tank on Concorde? Was the fuel in Concorde indeed warm enough to become volitile?

RIP those who perished.


for a video of the fuel ignition demo click this link and got 7min 30 seconds
YouTube - air crash TWA flight 800 part 4 (http://www.youtube.com/watch?v=4Houj7-9PEM&feature=related)

[fattboy]

There were firefighters who witnessed the take off. They reported seeing flames form the Concorde some distance short of where the strip of metal was found. This info came from a Discovery channel show I think. Anyone else see that show? Very sad day.

[bizdev]

I think you make a good point - as I understand it JETA1 will only ignite if it is a heated vapour - or atomised. It is difficult to understand how fuel flowing out of a hole that large would be either a vapour or atomised :bored:

[Brit312]

d747

I think you will find when an aircraft is flying at 200mph or more as this Concorde was, any fuel leak will atomise especially around the edges of the flow and could be ignited . This is why when dumping fuel, all sorts of precautions are taking to prevent the stream igniting.

From what I remember about fuel fires is that, it is the fumes that burn not the fluid, and perhaps in the TWA case it is at 53 degs [ F 0r C ?] that fuel starts to vapourize sufficently to give, above the fluid, a fuel/air mixture that will ignite given a spark source

[ChristiaanJ]

On the other - truly brilliant - Concorde thread, there was a comment made which indicated to me that those contributing to the thread, i.e. those that had either flown or maintained Concorde, had a different theory or opinion to that of the official crash report? Or have I mis-interpreted?bizdev,
Let's not forget that, as with virtually all crashes
- the final report will try to establish a "probable cause" and the most plausible theory for what happened,
- we are dealing with a chain of events, and not with a single event one can point at and say unequivocally : "that's the cause".

So it's normal, that there are different opinions and theories.
The BEA (with the judiciary breathing down their necks....) did make an effort to come up with the best and most plausible answers. Some of those answers were theories, because the evidence had been destroyed by the crash itself, and hence it was impossible to prove whether those answers were right or wrong.

So yes, in Concorde circles there were certainly differences of opinion, and different theories, some equally plausible, but equally unprovable.

Also, let's not forget the judicial enquiry had less to do with establishing the most probably cause and more with determining who was going to pay the bill......

CJ

[ChristiaanJ]

The "match in a pool of Jet A1" demo doesn't really have much to do with the matter (and with a big pool on boiling hot tarmac in the July sun, it won't be me tossing the match).

And we're not talking about "a spark", we're talking about fuel droplets swirling around in the undercarriage bay and being ignited by arcing, not sparking, from the 115V brake fan wiring.
In my experience, 115V is enough for a nasty arc...

CJ

[robertbartsch]

There is a two hour documentry on this that is playing on cable TV.

During the show, there are lots of theories given by British pilots, and British engeeners, etc. on why the bird crashed. These include, the metal Ti strip, the tire design, the missing wheel spacer, the fuel tank design, overweight condition, early engine shut off, wind direction, fuel pumped from the back to the front tanks, etc.

My view would be that it is a combination of factors but, given the history of shreaded tires, it seems irresponsible to not have modifed the fleet to include kevlar reinforced fuel tanks.

I never understood why these ships were built if breaking the speed of sound causes huge sonic booms which meant they could not fly over land at speed. It seems the fleet was doomed as a commercial venture from the start.

Is there any news on the status of the French trial? I thought it was a 4 month trial that started in February 2010.

[d747]

I guess I didn't think about the fuel being more of a "spray format" but when I think of the jet moving at speed then yes I agree

thanks for clearing that up

[bizdev]

"let's not forget the judicial enquiry had less to do with establishing the most probably cause"

I take your point

It would be interesting to hear where you differ from the official report in terms of probability

[Flexi]

F-BTSC (http://www.bea-fr.org/docspa/2000/f-sc000725a/htm/f-sc000725a.html)

Sorry, if it has been posted before!

[jcjeant]

Hi,

Sorry it's again in french (Concorde oblige .. lol)

Interesting third party complete analyse (with some graphics)
Crash du Concorde: la loi de Murphy (http://enperspective.pagesperso-orange.fr/concorde.html)

[ChristiaanJ]

F-BTSC (http://www.bea-fr.org/docspa/2000/f-sc000725a/htm/f-sc000725a.html)
Sorry, if it has been posted before!Flexi,
It's probably been posted dozens of times before, but not in this thread, so thanks !
I intended to look it up again myself to have the link at hand.

CJ

[Good Vibs]

Lots of questions, sorry...
Any truth in the story that the runway was resurfaced shortly after the crash?
All possible clues, ie scrape or tire marks on the runway were thus covered up?
Also was an AF747 with a very important French Politician on board on a taxiway waiting to cross the runway & saw the Concorde coming its way?

[ChristiaanJ]

Hi,
Sorry it's again in french (Concorde oblige .. lol)No problem in my case....
Interesting third party complete analyse (with some graphics)
Crash du Concorde: la loi de Murphy (http://enperspective.pagesperso-orange.fr/concorde.html)Interesting, yes, and well written. unfortunately not signed by anybody, which is no problem in itself, but it makes it difficult to judge the 'expertise' of the person writing the blog.

CJ

[ChristiaanJ]

Lots of questions, sorry...No need for apologies, that's what this thread is for.
Any truth in the story that the runway was resurfaced shortly after the crash?Quite likely, to repair some of the damage.
All possible clues, ie scrape or tire marks on the runway were thus covered up?Forget the conspiracy theories.... All scrapes and tyre marks were recorded in great detail very shortly after the accident (check the BEA report). After that, the runway was back in use, so most marks would have been obliterated by other take-offs and landings soon afterwards, anyway.
Also was an AF747 with a very important French Politician on board on a taxiway waiting to cross the runway & saw the Concorde coming its way?Yes.
The "very important French Politician" was the French president, Jacques Chirac.
Also, IIRC, there are a few snatches of video and some photos taken by passengers of that 747, that were helpful for the investigation. None were spectacular enough to make it into the press, it ssems.

CJ

[jcjeant]

Hi,

but it makes it difficult to judge the 'expertise' of the person writing the blog.
CH ... so maybe Cornus Henri ??
Crash du Concorde: Documentation (http://enperspective.pagesperso-orange.fr/livre_fnhmc.html)

[johns7022]

The video shows the plane on fire before rotation. > the crew decided to continue the flight > The plane was too heavy > couldn't fly on the remaining engines > crashed.

It's not rocket science....

It's a tragedy for the passengers and their families. It's a tragedy for the pilots...in that we will be stuck flying subsonic planes for the near future because everyone is too stupid to put decent pilots in the seats up front...

So instead of making faster planes, let's just continue making planes that go that same speed, but go farther, and add more automation so that we can stuff the front seats with less qualified pilots...

Yep...now that's really moving forward....

[Tonka777]

I thought they had to rotate, to avoid colliding with the 747 waiting to cross?

[bjornhall]

The video shows the plane on fire before rotation. > the crew decided to continue the flight > The plane was too heavy > couldn't fly on the remaining engines > crashed.

It's not rocket science....

It's a tragedy for the passengers and their families. It's a tragedy for the pilots...in that we will be stuck flying subsonic planes for the near future because everyone is too stupid to put decent pilots in the seats up front...

The aircraft was not on fire before V1; in fact, it was perfectly safe to fly at V1. The information available to the crew did not tell them the aircraft would be unsafe to fly; what they did know is that they were on a limiting runway and that a reject after V1 was guaranteed to result in a high speed overrun. The plane was not too heavy to fly on the remaining engines, it was just moving too slow to either climb or accelerate on the remaining engines (this was a Concorde, not a B747, they work rather differently). The fire was of such magnitude that no matter what the crew did, it would still have crashed; there was nothing the crew or anybody else could have done to control the fire. The aircraft did in fact continue to fly on the remaining engines until the fire eventually brought it down. Had they been moving faster and been able to climb the fire would still have brought it down before they could have landed (it only flew for a minute and there was nowhere to land within that time even if they had been able to climb a few hundred feet higher).

Had they rejected they would have gone off the end doing some 100 kts, with a plane that was already on fire, with nothing but grass to brake on and with the cargo village at the other end. It is extremely unlikely that anyone onboard would have survived the reject.

This was not a human error or human factors accident, but one of those rare purely technical events. The crash happened because a mechanism existed by which a tyre failure after V1 could render the plane unable to fly at a stage where it was too late to safely reject, leaving no sure options to avoid a disaster, and because FOD triggered that mechanism.

[Ex Cargo Clown]

This was not a human error or human factors accident

I'm desperately struggling to see how an aircraft that was overweight, had maintenance issues, out of trim limits, taking off downwind, with a non-captain commanded shut down of an engine developing thrust and then subsequently crashed had no human factors associated with it.

The mind boggles. :ugh:

[ChristiaanJ]

Ex Cargo Clown,

None of the items you mention was at the origin of the chain of events.

Some if not all had an effect on the sequence of events after the fire started.
But at that point the aircraft was doomed, even if none of the factors you mention had come into play.

CJ

[G SXTY]

From the BEA report - numerous pieces of aircraft were found between the end of the runway and the crash site, including; access panels, fuel tank fragments, tail cone structural parts and anti-collision light, ducting, hydraulic lines and shut-off valves, and parts of the left wing and fuselage structure. Many of these parts were damaged by fire.

Put simply, as ChristiannJ says, the aircraft was doomed from the moment an uncontrolled fire broke out. It is highly questionable whether they could ever have made it to Le Bourget – regardless of the number of functioning engines or the position of the landing gear.

[arearadar]

Well, as a flight deck visitor (air traffic controller, ppl) I remember we took off from Washington with a 5 knt tailwind component. Used every inch of the runway !!
The bigger problem was retraction of the gear with extremely high brake temperatures. After V2 we dropped the gear again to cool off the brakes.

Dave

[robertbartsch]

This was a technical marvel but a total commercial failure. Why?


Sonic booms cannot be tolerated over land, so the flights were largely restricted to oceans
The range was limited to shorter routes such as crossing the Atlantic
Fuel useage is very high compared with sub-sonic flights
Maintenance costs were very high
This is why other commercial supersonic aircraft will not be made anytime soon.

Many in the TV series said if the crash did not happen that the Concordes would still be flying today. I'm not sure on this one.

[ChristiaanJ]

This was a technical marvel but a total commercial failure. Why?Robert,
This thread is meant to talk about the Concorde crash, not to kick in open doors. Please ?
Many in the TV series said if the crash did not happen that the Concordes would still be flying today. I'm not sure on this one.Well .... what do you expect from a "TV series" ?
If the crash hadn't happened, BA and AF wouldn't have needed to do the 'return-to-service' modifications.
That's all.

The rest of the world would have gone on turning, "9/11", SARS, the Iraq war, the economic crisis, etc. would still have happened, and the reasons for ending the service in 2003 would have been unxchanged.

In an alternative universe, with the same or a better economy as in 2000, Concorde would have remained in service.
We were looking at keeping Concorde flying until about 2010 or maybe even 2013....
There were no technical obstacles that could not have been overcome.

CJ

[lomapaseo]

Bjornhall

I agree with the tone of your post above.

However I'm not sure that I agree with you that the fire would have been catastrophic to the ability to land.

The flames were certainly spectacular but it appears to me that the fire was entirely outside the structural interior and streaming in the slipstream.

I haven't seen any photos of the immediate area in the fire plume to tell if there is any metalization beyond the obvious post ground fire. If this was mentioned in the BEA report it would be significant, else to me the major issue was the shutdown of two engines.

[G SXTY]

They shut down the no. 2 engine only. The no. 1 lost thrust due to multiple surges, due most likely to ingestion of hot gases and/or tyre debris, and/or pieces of aircraft structure. Even if no. 2 had not been shut down, it is not unreasonable to surmise that it would have continued to suffer similar surging and loss of thrust to the no. 1.

Once again, and quoting directly from the BEA report:

"In any event, even if all four engines had been operating, the serious damage caused by the intensity of the fire to the structure of the wing and to some of the flight controls would have led to the rapid loss of the aircraft."

[skyfish2]

how yer doin dt?

[ChristiaanJ]

...I'm not sure that I agree with you that the fire would have been catastrophic to the ability to land.
The flames were certainly spectacular but it appears to me that the fire was entirely outside the structural interior and streaming in the slipstream.

Your answer is already here :
From the BEA report - numerous pieces of aircraft were found between the end of the runway and the crash site, including; access panels, fuel tank fragments, tail cone structural parts and anti-collision light, ducting, hydraulic lines and shut-off valves, and parts of the left wing and fuselage structure. Many of these parts were damaged by fire.
The aircraft was already coming apart, well before it could even have reached Le Bourget.

CJ

[robert f jones]

Despite the denial of obviously a well intentioned ChristianJ you have the whole episode in a nutshell. The final nail in the coffin was the Flight Engineer shutting down an engine without instruction from the Captain. My teaching by very experienced trainers over many years was never stop an engine on fire, if it's producing thrust, below 1000 feet agl.

Is there a result from the judicial review due anytime ?

[ChristiaanJ]

Despite the denial of obviously a well intentioned ChristianJ you have the whole episode in a nutshell. The final nail in the coffin was the Flight Engineer shutting down an engine without instruction from the Captain. My teaching by very experienced trainers over many years was never stop an engine on fire, if it's producing thrust, below 1000 feet agl.You clearly missed my point totally.....

This was not a case of an engine fire as such (and you learned your lesson well... you always think twice before shutting down an engine).

The aircraft itself was already on fire, scattering bits and pieces all over the landscape before it crashed.
If the engine had not been shut down, the aircraft might have flown another half-mile....
Even if it could have reached Le Bourget, it could not have "landed", with a fire already raging in one of the wheelwells.

Robert, like 'Cargo Clown', you make the major mistake of confusing the causes, that started the chain of events, with the various factors that determined the exact sequence until the crash.
To be crude... those factors only determined where the final fireball occurred, not why.

Is there a result from the judicial review due anytime ?I'd have to look it up, but IIRC the final verdict is due in December 2010.

CJ

[atakacs]

The aircraft itself was already on fire, scattering bits and pieces all over the landscape before it crashed.
If the engine had not been shut down, the aircraft might have flown another half-mile....

One thing I'm still wondering about is given the substantial leak how much fuel was still available in the affected tank until "natural" exhaustion (assuming obviously no cross feeding) ?

[lomapaseo]

CJ


Quote:
Originally Posted by lomapaseo http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/buttons/viewpost.gif (http://www.pprune.org/tech-log/426831-concorde-paris-crash-questions-facts-opinions-post5926908.html#post5926908)
...I'm not sure that I agree with you that the fire would have been catastrophic to the ability to land.
The flames were certainly spectacular but it appears to me that the fire was entirely outside the structural interior and streaming in the slipstream.

Your answer is already here :
Quote:
Originally Posted by G-SXTY
From the BEA report - numerous pieces of aircraft were found between the end of the runway and the crash site, including; access panels, fuel tank fragments, tail cone structural parts and anti-collision light, ducting, hydraulic lines and shut-off valves, and parts of the left wing and fuselage structure. Many of these parts were damaged by fire.

The aircraft was already coming apart, well before it could even have reached Le Bourget.

CJ


Well since we are a having a sharing of open minded opinions I will venture an opinionated reply.

Stuff found on a runway after a plane takes off is typically mechanically liberated over a very short time. I thought it unlikely that a fuel rich fire dependant on swirling airflow would generate enough heat to release debris while still on the runway. Albeit ccorching of local areas of the wing including some flap damage. So I continue with my own opinion that the thrust performance degradation of the flight during climb out was the archilies heel.

Neither the initiating first layer of swiss cheese nor the final layer of cheese where the aircraft falls out the sky is of interest to me either. Instead my thoughts are to the multiple layers of cheese that were thought to be unlikely to line up in the middle.

Unfortunately the courts have a myopic way of assessing blame to satisfy the greater public and that is fed by the favorite plantif lawyers term of " if not for the *** " (pick one layer of cheese) and assign the blame. While my modus operandi looks for the barrier layers that were intended as "in-spite-of"

[bjornhall]

I think the final two findings in the report are interesting:

Many pieces of the aircraft found along the track indicate that severe damage to the aircraft’s structure was caused in flight by the fire.
Even with the engines operating normally, the significant damage caused to the aircraft’s structure would have led to the loss of the aircraft.
They would have had better access to and more time to consider the available evidence in person than we get from just reading the previous chapters of the report. I am not an accident investigator though. :)

I also think it is interesting that the VMCA with two engines out and the plane intact is 157 kt, and the aircraft was flying faster when engine 1 had its final surge; still the aircraft described what looks similar to a VMCA roll over. It should have been controllable with two engines out if it was otherwise intact, although rate of descent would have been high. Even before that investigators could start seeing discrepancies between the control deflections commanded and the aircraft behavior, indicating the flight controls were being progressively destroyed. The elevons on the left wing would have been in or near the flame.

[bjornhall]

This kind of stuff should not be left unanswered:

an aircraft that was overweight

It was about one ton overweight. A lot on a C172, 0.5 % on a Concorde. It had no influence on anything. Not good, but not a factor.

, had maintenance issues,

Are you talking about the missing spacer? Or the intermittent fault in one out of three flight control channels, which was an acceptable defect in the MEL? Again, not good, but no factors.

out of trim limits,

Huh? Where did you get that idea from? :confused: All available data says it was inside limits.

taking off downwind,

Wind was light and variable at the time. The tower reported 8 kt tailwind may or may not have been present on the runway during the takeoff (it would have been present at the wind sensor, which is not the same thing), but analysing the aircrafts actual performance during the takeoff indicates it was not present.

with a non-captain commanded shut down of an engine

The captain ordered fire drill at the same time when the flight engineer announced "shut down engine 2". So the captain did order the shut down.

developing thrust

Hardly. Engine 2 never recovered from the surges, and was producing no more than 15% of thrust when it was shut down. Shutting down engine two put the other three engines in contingency, increasing the thrust on these engines. They probably got more thrust when they shut down engine 2, not less.

Could engine 2 have recovered and started producing thrust had it not shut down? Maybe; I doubt it, but maybe. But with a fire alarm from engine 2 it would have been shut down in short order anyway. Keep in mind that engine 1 was less affected than engine 2, it was not shut down, and it still surged a short time into the flight. Engine 2 would not have ran for long even if it wasn't shut down.

[bjornhall]

However; could this have played out any differently? Possible (right...) alternative outcomes:

Miracle outcome #1: The crew rejects at some 190 kts and roll onto the grass doing at least 100 kts. Miraculously they aircraft does not collide with any obstacle and stops more or less intact on the grass. A few people make it out despite the fire. For the rest of aviation history this event is held up as yet another example of a needless crash caused by the captain's flawed decision to reject above V1, since "everybody knows" that the aircraft could have flown away and landed safely had the takeoff not been rejected.

Miracle outcome #2: The crew makes a snap decision to land on Le Bourget, somehow manage to line up with the runway and land somewhere close to the threshold, brakes are able to slow it down despite being massively above max landing weight, and the aircraft stops without hitting any obstacles (the last point is incredible given the surroundings at Le Bourget). A few people make it out despite the fire.

Miracle outcome #3: By some kind of magic both the flight controls, systems, structure and engine 1 survive the onslaught of the fire for another 45 seconds or so; I have no idea how that could be possible but let us assume it is. By that time the fuel in the breached tank would be depleted. The fire did not damage any other tanks (big assumption here), so the fire actually stops at this time. The crew manage to nurse the damaged aircraft, left elevons all but burned off and unknown other systems malfunctions, to a safe landing. Everyone lives happily ever after.

Would any of those three miracles have been possible? To my mind #2 and #3 are pure fairy tales, and the chance of someone surviving miracle #1 seems remote. Possible, maybe; likely, not a chance.

Yet those who argue that this accident had anything whatsoever to do with the crew's actions are placing their bets on the crew managing to achieve one of the three miracles above. I am not buying it.

[DozyWannabe]

Hokay - so as a secret aviation nut I followed events at the time very closely, but it was 10 years ago, so I'm working purely from memory here...

EXWOK - if the scenario could not be reproduced with setup as prescribed by the flight manual, did they not attempt to reproduce in accordance with the theory that the fuel tanks were slightly over-filled due to not burning as much on the taxi as they were expecting?

lomapaseo - The hydraulic shockwave theory and the fact that no fuel tank had ever been penetrated by a tyre fragment are compatible, because no penetration is required if it was the fluid dynamics of the fuel that punched the hole in the tank, not the tyre. Another interesting (if somewhat grim) theory on fluid dynamics provides an addendum to the Aloha Airlines 737 accident.

robertbartsch - Have a look at the other thread regarding BA's modifications to the main gear in the wake of problems caused by tyre bursts - the later kevlar modification obviated the need for it and it was subsequently removed. AF did not perform the same modification, but they were using different tyres with completely different characteristics. In fact, the new tyre technology developed in the wake of the accident probably obviated the need for the Kevlar lining according to one engineer, but at that stage the work was already underway. You've also got to remember that despite the unprecedented level of R&D that went into Concorde, she is very much a design of the 1960s. System-level failure engineering to the extent of the multiple events that caused the accident didn't come around until the mid-late 1970s, in the wake of the very public DC-10 incidents that occurred around that time.

I'm a little confused by the invective surrounding the FE's engine shutdown decision, especially as so many posts on here bemoan the disappearance of the FE from the flight deck, in part because they were qualified engineers and capable of independent thought and action. Bjornhall and ChristiaanJ are right - all evidence suggests that the structural failures caused by the fire would have doomed the aircraft whether number 2 was turning and burning or not.

I can understand the attitude of those in the documentary (I remember Captain John Hutchinson from a prior appearance on a BBC Concorde special in the late '80s - particularly memorable for his ****-eating grin whenever he was handling the controls) saying that it should never have happened and that Concorde should not have been taken out of service - she was and will always be an aviation gem and a source of pride to anyone involved with her. But I believe that even if Airbus could have been persuaded to continue producing parts, even if AF could have been persuaded to keep her flying, and yes - even if BA had bitten the bullet and gone it alone (though the unseemly haste with which they disposed of the airframes suggests that the end of Concorde operations was more of a relief to BA Corporate than they are prepared to admit) - I very much doubt Concorde operations would have survived the multiple global economic slowdowns of the last decade - and as such, going out with her head held high when she was still in her prime was a far better way to go than meekly submitting to dwindling demand over several years.

[ChristiaanJ]

I've only just started to re-read the original BEA report, to clear up some of the tank 5 issues in my own mind.

Tank 5 is nominal 9090 litres. I haven't found the estimated value for the fuel leak yet, so I don't know yet how long it would have taken for tank 5 to empty through the leak. Does somebody already have the figure?

However, there has been a lot of talk about "overfilling".
Now, first of all, this is (was...) a normal practice for range or weight limited flights. Let me explain.
During refuelling, there would be an automatic cut-off for each tank, when the tank was about 95% full (fuel quantity sensor).
Afterwards, it was possible to add about 1500 litres, by a carefully measured "topping up" of each tank, to compensate for the 1 to 2 tons that would be used during taxying.

This "overfilling" and the resulting lack of airspace has been blamed for the 'oil-canning' (hydraulic shockwave) of tank 5, it seems.

Well, we now have a minor problem....
The BEA report states that only about 300 litres (about 500 lbs) was 'overfilled', and only into tanks 1, 2, 3 and 4, NOT into tank 5.

CJ

[Mr Optimistic]

Did someone say earlier it was on just two engines ? For the tank, presumably the geometry of the tank determined which part failed (it's not like spalling off the back side of RHA through a tensile reflected wave).

[ChristiaanJ]

As for the condition during the short flight, the documentaries all point to the condition inside the passenger cabin as being unbearable, if so perhaps a case of the sooner the better ?Well, the "documentary" vultures all would love that detail wouldn't they?
I still think you remark is revolting....

CJ

[Mr Optimistic]

Hope it wasn't the case but... (to avoid confusion with your reply I have edited my post if it caused offence).

[jcjeant]

Hi,

A bit away from a main topic ...
I do not see anything shocking in about Optmistic post
It is a fact that passengers should not be in a comfortable environment.
Talking about death should not be a taboo .. since no pun .. death is an integral part of the life of human beings.
Perhaps in some societies sweetened .. People were packed in a certain way and can not even bear to be about death and its realities.
It is therefore not surprising that more and more death leaves indifferent .. or is something to hide ..
Let us die in indifference.

[DozyWannabe]

This "overfilling" and the resulting lack of airspace has been blamed for the 'oil-canning' (hydraulic shockwave) of tank 5, it seems.
Well, it was one of the theories put forward - as has been said many times, the only incontrovertible evidence was completely destroyed by the fire. Could the FE have transferred some of that fuel to tank 5 after pushback?

One of the things I forgot in my last post was the reference to eyewitnesses who stated that they thought they saw flames before F-BTSC hit the part of the runway where the debris lay. While it would be churlish to disregard it completely, experience shows that of all the types of evidence available, eyewitness evidence tends to be the least accurate - and in fact one of the recurring factors is that human beings seem to be bad at remembering at what point in the sequence fire was involved - in many accidents where the craft was intact until it hit the ground, contemporary eyewitnesses have said that the craft caught fire in the air.

[ATC Watcher]

that human beings seem to be bad at remembering at what point in the sequence fire was involved

Absolutely. This was very well explained during a presentation I followed some years back by a Psychogogist ( I have to see if I can find back the references ) who explained that when your brain register a shock ( like witnessing an accident) the chain /sequence of events to that shock very often is deregulated. Only a camera show this. Having said that , what is a bit disturbing in the "witness" reports is the fire brigade testimony(ies)who said the aircfat was already on fire when it passed abeam them, and that was before the metal strip . This was the main part of the Continental defence during the trial.

One of the controllers on duty that day said to me that from the start and during accelleration the noise was not the normal noise a Concorde makes during take off.
But again perhaps that was due to the above post accident phenomenae.

[GlueBall]

It is highly questionable whether they could ever have made it to Le Bourget – regardless of the number of functioning engines or the position of the landing gear.

This simulator training mind set is still with us today; because if you don't get the airplane on a runway then you fail your sim check.

The Concorde only achieved 200' altitude [lower than the height of the air traffic control tower], and the copilot had warned Capt Christian Marty at least three times of decreasing airspeed....but Le Bourget runway was in view only 7 miles straight ahead.

My take is that the airplane should have been landed on a farmer's field straight ahead. It would have been a controlled crash, rather than an in flight stall and uncontrolled crash.

There was no logic in attempting to stay airborne without sufficient airspeed.

[atakacs]

My take is that the airplane should have been landed on a farmer's field straight ahead. It would have been a controlled crash, rather than an in flight stall and uncontrolled crash.


Agreed... But given the sheer size of the fire and the amount of fuel on board the survivability of such a controlled crash was nil.

That being said it is pretty clear that the pilots where not aware of the nature and scope of the fire. Remember that it took weeks to actually understand that it was not an engine fire !

Not specific to this accident but I still wonder why some micro cameras are not strategically placed on all modern airframes - they might save quite a few life IMHO

[ChristiaanJ]

A few more remarks about tank 5 (the one that was at the origin of the huge fuel leak).

First of all, for the moment, the theory that the tank was "full to the brim", with very little air space left, which led to the impact of a large piece of tyre provoking a shockwave in the fuel, knocking out part of the tank structure, is still the most likely one.

It's also one of the essential parts of the sequence of events that led to the crash, (unlike all the other details being dragged in, like the wind or the exact take-off weight).

It has been proved difficult, if not impossible, to reproduce the exact conditions during tests.... not that amazing really... but the huge piece of tyre and the panel punched out of the tank were there on the runway for all to see, even if the mechanism wasn't fully understood.

Second, as mentioned earlier, only tanks 1 to 4 had some fuel added during ground refuelling ; however (as somebody just reminded me), the flight engineer could use 'override' switches on the fuel control panel to top off tanks like tanks 5 and 8 to 'fine-tune' the tank contents and the CG during taxy, and probably did, so there is nothing very mysterious about tank 5 being "full to the brim" during take-off.

Third.... I think, in the context, "over-filling" is an unfortunate expression that has caused unnecessary confusion.
It evokes images of "over-doing it" or "over-eating".... something that maybe should not have been done.

In reality, maybe a term like "manual topping-up" would have been better.
The procedure is perfectly normal, without any danger in normal operation, and was used regularly.

It's exactly like your car at the petrol station... the petrol pump will cut out automatically when the tank is about 95% full. You can squeeze in a few more litres if you want to.
For your car it's just a matter of getting the pump to show a round figure in pounds (or euros), for Concorde it was a matter of adding the few hundred litres that would be burned during taxy.

So, on Concorde, there was nothing wrong with "topping up" tank 5 "to the brim", whether done during refuelling or by the F/E during taxying.

What nobody could have foreseen was that it would become one of the primary items on that ghastly day in July 2000....

CJ

[lomapaseo]

The fluid level in a fuel tank contibuting to this accident was in my view unforseen by the industry in general. It is easy to use hindsight and theories to propose how it might have contributed etc.

Both in the past and presumably in the future engineers and designers have been caught by surprise with a new lesson learned. Obviously lots of fuel tanks have been overfilled without ever seeing such a result.

The key to the recognition that in this specific event it might have been significant was the finding of the tank piece on the runway and its shape and fracture surfaces. To my eye they were unique and I have only seen them before associated with ballistic impacts in thick aluminum. Of course the more scentific evaluations would have to be made in a metalugical lab.

[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]

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]

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 (http://www.concordesst.com/accident/englishreport/a4.html)

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.

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! :ugh: 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]

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]

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]

Here is one , not sure it is the one you mean though..
Vidicom : Movie Frameset (http://www.vidicom-tv.com/concorde/frameset_4.htm)

[The late XV105]

Video animation of the flight (http://www.vidicom-tv.com/concorde/frameset_4.htm)

(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

[EXWOK]

The yaw induced by the reduced thrust on 4 was negligible, you really didn't notice it in handling terms.

[robertbartsch]

I have not seen much press on the progress of the French trial. At the start early in 2010, it was supposed to last 4 months.

I'm I correct in assuming that the French judges and not a jury will conclude who, if any parties are responsible for the crash and loss of life?

What are the possible sanctions under French law; monetary damages, jail sentances?

Thx..

[ChristiaanJ]

Robert,
There has been some reporting in the French press, and some discussions on French aviation forums.

Generally I tend to make a wide detour around canine manure (which I consider this court case to be), but if enough people want to know more, I can have a look and try and do a summary.

CJ

[lomapaseo]

What are the possible sanctions under French law; monetary damages, jail sentances?


Press releases both during and after the trial will probably suffice for the publics memory bank.

[robert f jones]

Reference "canine manure", we may have something in common after all !
My last flight in BA uniform was, at my request, a sny ride on Concorde to JFK and return. I knew a number of Concorde crew plus a few UK AAIB people and therefore am indoctrinated in the British attitude towards the Air France accident.
Where it appears we may have a mutual agreement is the judicial interference whereby the AAIB were barred from certain parts of the accident investigation, contrary to Annex 13, accepted by every other nation.
It would be appreciated if you could make serious interested parties know, by this forum, the outcome of the current court case when it finally concludes. Current thinking amongst my former colleagues (BA and CAA) is that it will be a foregone conclusion based on nine year old evidence.
The French people involved in the trial deserve better consideration after so long in the Industry.

[ChristiaanJ]

...It would be appreciated if you could make serious interested parties know, by this forum, the outcome of the current court case when it finally concludes. Current thinking amongst my former colleagues (BA and CAA) is that it will be a foregone conclusion based on nine year old evidence.Robert,
IIRC, the date of the final "verdict" is either December 2nd or 3rd. And yes, no problem about reporting it here once it happens.
It'll probably make the UK news too at the time, but I'll do my best to follow the French news and translate anything useful.
The French people involved in the trial deserve better consideration after so long in the Industry.I totally agree there.

CJ

[atakacs]

One further question here... what was involved for an engine fire alarm to go off ? My understanding is that initially none of the engines were actually on fire ?!

[ROKNA]

@ Misterredmist

Engine 4 was always restricted until past 80 knots

Due to the vortex rolling off the side of the delta wing it caused the air flow entering engine 4 to rotate in the opposite direction to the engine turbine stages. Beyond 80 knots it didn't cause a problem.

This obviously only effected one side of the aircraft as on the other side, engine 1 the air flow coming off the side of the wing was rotating in the same direction as the engine.

So normal procedure of which the all concorde crew would be familiar

[ChristiaanJ]

One further question here... what was involved for an engine fire alarm to go off ? My understanding is that initially none of the engines were actually on fire ?!atakacs,
If you're seriously interested, get yourself a copy of the Concorde flying manual (available on the internet). Until then, I think it's somewhat pointless trying to second-guess the BEA on such basic matters.

CJ

[M2dude]

I have deliberately not posted in this thread (although the totally one-sided view of things technical from France has tempted me on several occasions; no offence CJ). I'll continue to resist posting any of my own opinions here (and those of virtually the entire British Concorde family) as long as I can NO MATTER HOW MUCH ONE-SIDED the technical retorts are seen to be. (Can't promise though, and anyway if anyone wants my views on any of this stuff posted in this thread, feel free to pm me).
OK, just a couple of technical issues then:

atakacs

One further question here... what was involved for an engine fire alarm to go off ? My understanding is that initially none of the engines were actually on fire ?!

No need to worry about 'second guessing the BEA' in all its renowned abject impartiality, I'll give you a technical answer here no problem. The Graviner FFFD fire detection system used on Concorde used two dual capacitive detection loops; if a loop went short circuit it would generate a fault and NOT a fire warning, and for a FIRE warning to be generated BOTH loops would have to detect the fire. But, there is a big BUT here; if BOTH loops detect a fault, then after some modifications to the system carried out in the 1980's, this was deemed to mean that both loops had burned through, and a fire warning was generated. We can only postulate that maybe this happened here; the fire wire elements surrounded the engines, being mounted to the titanium centre wall and top heat shield, and around the jet pipes, as well as to the engines themselves.
ROKNA
Engine 4 was always restricted until past 80 knots Due to the vortex rolling off the side of the delta wing it caused the air flow entering engine 4 to rotate in the opposite direction to the engine turbine stages. Beyond 80 knots it didn't cause a problem. This obviously only effected one side of the aircraft as on the other side, engine 1 the air flow coming off the side of the wing was rotating in the same direction as the engine.
Good points here Rokna, but the figure was 60 KTS, not 80 KTS, above which a solenoid latched switch on the F/E's station was automatically released by an ADC speed signal. The engine control restriction was to N1 alone (By restricting the primary nozzle area)and not N2. the fold-over effect diminished to an acceptable level at 60 KTS, it took a little more IAS until it disappeared altogether. Although there obviously was a restriction to take-off thrust this was minor, and as EXWOK previously stated here, barely noticable during take off.

Dude :O

[henra]

The final nail in the coffin was the Flight Engineer shutting down an engine without instruction from the Captain.


Are we absolutely sure that it was a commanded Shutdown of Engine #1 ?

Looking at the FDR Data between Timestamp 97659 and 97661 the SFC and EGT still slightly increase whereas EPR starts to decline.
At 97661 also then SFC drops off.
In a comanded shutdown, I would expect rather the opposite.
On the other hand rudder right is immediately albeít only little increased. So the Pilot must have been expecting something or maybe he just noticed the engine spooling down

I agree that shutting down Engine #1 was the final blow.
You can come to that conclusion also from the FDR data.
It takes until 97661 until the aircraft starts yawing left (Lateral accel left) and until 665 until rolling left and pitching up, increasing altitude and at the same time loosing speed.
You also see the control column right input significantly increasing after 97665.
So the Sequence appears to be: Shutdown (voluntary or not ?) of Engine #1, followed by yaw to the left, followed then by roll left and pitch up, losing speed at the same time.

Seeing the data, I'm not really convinced that the wing/TE really folded up as some reports suggested. Pitch and AoA increase rather slowly and continuously (not aprubt) and also largely in sync. It appears the wing still produced significant lift.
But looking at the graphs I got the feeling that the Control surfaces on the left wing might have been lost/ineffective relatively early in the flight.
From 97647 on Control Wheel position largely correlated between Nose down and aileron right.
Looking at the graph between 647 and 651 control wheel right input + Nose Down was applied, vet the pitch increased 3- 4° Nose up at the same time
This to me implies that a roll right might have caused nose up pitch so the Pilot tried to compensate for that once he firgured out.
One could conclude from that that the Left elevon was ineffective/lost at that point in time.

Re initial cause i.e. metal strip.
That one should be rather doable to sort out.
On the vertical acceleration you see a bump at 97586. That should be the disintgration of the tire.
You would have to calculate the corresponding position based on speed and elapsed time and compare it to the place where they found the strip.
For BEA that should be feasible. So at least they should have a clue.

[atakacs]

the fire wire elements surrounded the engines, being mounted to the titanium centre wall and top heat shield, and around the jet pipes, as well as to the engines themselves

Thanks for this technical explanation which is all I was asking for, sparing me the need to dig into the Concorde engineering manuals ;)

So from the above (sorry I'm sure I could find this info elsewhere too) they where multiple fire wires and shorting of two of them would yield to the fire alarm ?

[M2dude]

Yes that is quite correct atakacs. Originally at entry into service Concorde was fitted with an ultra violet detection system, designed to detect combustion chamber breakouts etc., but this was found to be totally ineffective (useless in fact) in service. When this system was replaced in the early 1980's with an enhanced version of the original fire detection firewire system, the fire detection logic was changed from it's original philosophy: Originally a single loop detecting a fire gave no warning at all; this being changed to a FAULT (not a FIRE) warning, and dual loop low insulation resistance now resulting in a FIRE warning, instead of just a FAULT. The basic Graviner FFFD philosophy was retained, where both elements would have to register a FIRE condition before giving the alarm. The fire detection network was arranged as two loops per engine in two long series independent loops running the entire length and breadth of the engine bay. If there was a break in the loop, then although the test system would not work, both halves of that loop would still give you adequate protection. A dual SHORT (which is what had occurred in the 1982 engine fire in G-BOAF) tends to occur when the loop wiring is burned through; hence the revised philosophy.

Dude :O

[PBL]

It is interesting (I use the word loosely :) ) to read here the speculation about the Concorde crash, much of it introduced and indeed resolved within a few years of the crash. I guess if unfounded speculation doesn't succeed the first time around, one can always wait 6 or so years and then reintroduce it.........

It prompted me to read again the analysis by Bernd Sieker, in his Diplom thesis at http://www.rvs.uni-bielefeld.de/publications/Diplom/sieker.pdf (the second half; the first half describes a causal-analysis SW toolset which has been superseded by the SERAS suite).

Contributing to this analysis was an exchange of information and views with the Chief Aerodynamicist of Concorde at the time of service introduction.

PBL

[Feathers McGraw]

Having read this thread after reading many of the previous Concorde crash threads on PPRUNE, I do note that no one has mentioned that a likely reason for the eventual failure of the No 1 engine was that it ingested pieces of runway edge lights damaged as the undercarriage ran off the left edge of the runway just before the aircraft became airborne.

Now the engine may well have surged and run down due to increasing hot gas ingestion but the surge margins were likely to have been compromised by FOD from that light.

I can't remember exactly what was said by the BEA about this and I don't want to go and read the report again (at 3am!) right now.

If I'm wildly wrong here I'll shut up. It's a small detail anyway, as others have said once the fire started after V1 (or even before I suspect) the result was inevitable. All extra thrust from the engine could have done was to alter the impact point.

What I am interested in, but don't think a definitive answer will ever emerge about it, is why the tank wall section was blown out.

I understand the hydraulic shock, but with an air space above the fuel I can't see how the internal tank pressure could rise enough for this to happen. Under this condition the air would have compressed, absorbing the energy. Now I'm not saying that the tank wasn't ruptured by a fuel shock wave inside it, but I thought the normal operating procedures were required to ensure that there was an air space in all the tanks.

The only scenario I can think of that leads to the ejection of that piece of tank wall is that the shock wave travelled backwards down the tank and the fuel surged up excluding the air at the back of the tank and rupturing it with a local over-pressure rather than one in the whole tank.

Does that make sense? It does worry me that what happened could not be recreated even with the knowledge of the size of the rubber piece, its probable velocity and the probable fuel state of that tank.

Does anyone know how these tests were done? I don't imagine they were able to repeat this on an actual Concorde airframe.

[ChristiaanJ]

Feathers McGraw,

To save you wading through the entire report:

- § 1.16.9 deals with the detailed inspection of the engines,
- § 1.16.7.2 deals with tank 5.

...a likely reason for the eventual failure of the No 1 engine was that it ingested pieces of runway edge lights damaged as the undercarriage ran off the left edge of the runway just before the aircraft became airborne.See § 1.16.9.
In my view, the FOD damage to engine 1 sounds far more consequential than would be caused by hitting a frangible runway light.Also I would expect it to be crushed, with debris being thrown sideways and to the rear, not forward.

What I am interested in, but don't think a definitive answer will ever emerge about it, is why the tank wall section was blown out.See § 1.16.7.2.
I would say that what happened is clear enough: a fragment of the tyre hit the underside of the tank, and an adjacent piece of the tank wall about a foot square was "punched out".
Exactly how is less clear, and yes, a definite answer is unlikely to emerge. But the various 'scenarios' mentioned in the report make sense, even if the various trials did not provide a clear-cut answer.

I understand the hydraulic shock, but with an air space above the fuel I can't see how the internal tank pressure could rise enough for this to happen. Under this condition the air would have compressed, absorbing the energy. Now I'm not saying that the tank wasn't ruptured by a fuel shock wave inside it, but I thought the normal operating procedures were required to ensure that there was an air space in all the tanks.Not really... refuelling would normally be cut off automatically with the tank 95% full (94% in this case according to the BEA report). But it was also allowable to carefully "top up" the tanks even further, and by using the 'override' switch, some more fuel could also be moved during the taxying.
So the remaining air space may well have been minute.

The only scenario I can think of that leads to the ejection of that piece of tank wall is that the shock wave travelled backwards down the tank and the fuel surged up excluding the air at the back of the tank and rupturing it with a local over-pressure rather than one in the whole tank.Read the report... the shock might well have reached the adjacent panel even before it had a chance to compress any remaining air... and, with the aircraft accelerating, that air would have been a small pocket in the front of the tank.

Does that make sense? It does worry me that what happened could not be recreated even with the knowledge of the size of the rubber piece, its probable velocity and the probable fuel state of that tank.The report admits they could only do a limited amount of tests, and none probably fully reproduced the exact conditions of the accident.
It doesn't really 'worry' me... as I said we have a pretty good idea what happened, and plausible answers to how it happened.

Does anyone know how these tests were done? I don't imagine they were able to repeat this on an actual Concorde airframe.It's described in § 1.16.7.2. At least one of the tests did use actual Concorde panels (I can't remember from which airframe), but indeed, none were done on a complete Concorde.

CJ

[Chu Chu]

This is probably far fetched, but I wonder if the impact and displacement of fuel could have caused a trapped pocket of vapor-laden air to ignite by "dieseling"? I guess it would require a trapped volume of air small enough to be greatly compressed (and heated by that compression) without absorbing all the excess pressure, but yet big enough to cause damage when it ignited. And, of course, the vapor concentration would have to be between the upper and lower explosive limits.

It may well be that all those conditions couldn't have occurred in the tank. But conceivably it's a way to explain tank damage beyond that attributable the excess pressure alone. I didn't see the possibility discussed in the BEA report -- though I guess the most likely explanation for the omission is that it wasn't a possibility . . .

[Feathers McGraw]

Thanks for that response Christiaan, I see several things there that I had not considered, particularly that rearwards movement of the tank 5 contents leading to no air space at the rear of the tank.

I know that M2Dude has said in the past that he was sure he'd seen a photo that was not included in the report showing something about the position of the tank 5 override switch. But there is nothing certain about that.

It does seem that, with some topping up, the conditions I was thinking about were more likely to be present in tank 5.

I'll withdraw my "worried" feeling, I think I can see more clearly why that piece of tank wall was punched out now.

As for engine no 1, I'm not quite sure I would regard a runway light as being very frangible. I see what you're saying about the likely path of such debris, but I was sure that I'd read somewhere that the investigators thought that it was likely to have entered that engine.

[ChristiaanJ]

This is probably far fetched, but I wonder if the impact and displacement of fuel could have caused a trapped pocket of vapor-laden air to ignite by "dieseling"?...I didn't see the possibility discussed in the BEA report -- though I guess the most likely explanation for the omission is that it wasn't a possibility . . .Chu Chu, have a look at § 1.12.1.9 in the report. There is a large "splat" of unburnt kerosene at the point where the traces on the runway start, and only after that the soot (from the partially burnt fuel) starts. So the leak came first, the ignition only afterwards.

I like your reasoning... but what's the pressure in a diesel engine at the moment of ignition? And once the vapor-laden air had 'dieseled', that would be it; it still wouldn't have ignited the remaining fuel (no air left). Not to mention that a fuel tank is not a diesel engine cylinder... the 'diesel explosion' would have blown out the top of the tank above the air pocket.

We already have a hole and a big fuel leak, with enough ignition sources available outside, so IMO there's no real need to look for a more far-fatched scenario.

CJ

[M2dude]

FeathersMcGraw
I know that M2Dude has said in the past that he was sure he'd seen a photo that was not included in the report showing something about the position of the tank 5 override switch. But there is nothing certain about that.
I did some digging a few months back. It was not a photo as I first thought, but the verbal testimony of a former colleague who was assisting at the crash site in Gonez. He told me that that the Tank 5 inlet valve over-ride switch WAS broken, but the stub appeared to be locked in the OVER-RIDE OPEN position. (It was a DOWTY lever-locked type of switch; once engaged in the detent only a firm outwards motion could release it).
Either way I don't think that there is any real doubt about the final hydro-dynamics of the section of wing lower skin being 'blown out', the tests and investigations here do seem to have been extremely thorough.
ChristiaanJ
In my view, the FOD damage to engine 1 sounds far more consequential than would be caused by hitting a frangible runway light.Also I would expect it to be crushed, with debris being thrown sideways and to the rear, not forward. Point taken my friend, but the damage could still be attributed in my view, at least partially, with the ingress of the runway light and it's fittings; we just cannot discount this totally. Either way, we are faced with an engine producing very little thrust and it's neighbour (still producing some thrust) being shut down some 20 KTS below V2 and below 100' AGL. The lack of serious damage to engine 2 compressor seems to indicate that the surging and lack of thrust was due to fuel ingestion and could in all probability have recovered, but I suppose we'll never know for sure.
One final point that I would like to re-iterate (although academic in terms of what finally happened to the aircraft. The BEA report statesThe two loops must detect the fault simultaneously to set off the ENGINE FIRE warning. This results in a red flashing warning light lighting up on the fire handle of the engine in question, accompanied by an aural alarm (chime), then by a gong and the illumination of the corresponding red ENGINE warning light on the Main Warning System. The BEA certainly missed yet another point here, in that a simultaneous loop fault (NOT JUST A DETECTED FIRE) would ALSO generate a fire warning; this was a deliberate design feature of modifications carried out to the original GRAVINER FFFD system in the mid-80's.
As far as the rest of this tragic event goes, well I'd rather not comment any further here; this is for once a generally well informed (and civilised) thread.

Dude :O

[Chu Chu]

Christiaan,

I was positing a diesel explosion to explain the tank damage, not the subsequent ignition of the leaked fuel. But you're right -- such an explosion would be much more likely to damage the top of the tank.

[ChristiaanJ]

FeathersMcGraw
I did some digging a few months back. It was not a photo as I first thought, but the verbal testimony of a former colleague who was assisting at the crash site in Gonez. He told me that that the Tank 5 inlet valve over-ride switch WAS broken, but the stub appeared to be locked in the OVER-RIDE OPEN position. (It was a DOWTY lever-locked type of switch; once engaged in the detent only a firm outwards motion could release it).
Either way I don't think that there is any real doubt about the final hydro-dynamics of the section of wing lower skin being 'blown out', the tests and investigations here do seem to have been extremely thorough.Thanks for confirming something I already heard, but was not fully sure about.
Even less air in tank 5 than the 6% "at dispatch", due to transfer during the taxy, simply makes the hydro-dynamics of the event even more likely.
Interestingly, according to the BEA report, the tests done on tank dummies were done with them filled to 100%, so they were already thinking along the same lines.

ChristiaanJ
Point taken my friend, but the damage could still be attributed in my view, at least partially, with the ingress of the runway light and its fittings; we just cannot discount this totally.I'm not discounting it either, but is there any stainless steel in runway lights, as was traced in #1 engine?

As far as the rest of this tragic event goes, well I'd rather not comment any further here; this is for once a generally well informed (and civilised) thread.
DudeI couldn't agree more.
But if this thread helps a few people to get a better view of what happened, I would say it will have fulfilled its function.


Maybe I should add one thing here....
When I first heard about the crash, my first reaction as an engineer was "Oh no... what did we do wrong...?"
Since then, I've tried to learn as much as possible about what happened, and sometimes (like here) tried to pass it on.
And yes, like M2dude, I've mostly refrained from commenting on my opinion of the "why", and will at least try to continue to do so.

As I said, it was partly the reaction of an engineer....
On Dec. 29, 1972, a Lockheed 1011 TriStar (Eastern flight 401) crashed in the Florida Everglades.
Within the next few months, and well before the final report came out, we had information about one of the contributary factors to the crash, an incoherent display of the autopilot mode.
And yes, when we started looking at the Concorde system, we found the same possible fault was hidden in the system.
We did the necessary modifications within weeks (and this was long before the aircraft went into service).

In 2000, I was no longer working on Concorde.
But I had the same gut reaction... "what did we do wrong?" .... "what are we going to do, so it never happens again?".
Sure, I was no longer involved... but somehow it was still "my aircraft".

CJ

[roulishollandais]

Puisque vous êtes de France, je reste en français.

Le 10 juillet EADS a commencé de mettre en bourse ses titres, à cet effet il a dû déposer à la COB (Comission des Opérations en Bourse) une "documentation générale" enregistrée le 12 mai 2000 sous le numéro R 00-223.

Ce document est très complet, afin d'éclairer l'éventuel acquéreur d'actions des chances et des risques pris financièrement.

Tous (...) les avions et hélicoptères d'EADS y sont décrits... ou presque !
Un seul avion manque : CONCORDE !!! qui se crashe quinze jours après, après avoir décollé EN FEU devant l'avion de Chirac, et devant le bureau de Spinatta.

Dès que l'enquête est ouverte, c'est bien "EADS" qui se révèle être en charge de Concorde !!!

Les accords entre Aérospatiale et Matra signés, sous la houlette de Dominique Strauss-Kahn, en vue de la création d'EADS ont été signés en juin 1999... en même temps qu'Anne Sinclair, son épouse ,
récupère enfin une cinquantaine d'oeuvres de son grand-père que les Allemands ne voulaient pas restituer ! (dont les célèbres Nymphéas de Monet).

Ne cherchez pas plus loin si vous avez mal fait quelque chose !
Concorde ne devait plus voler, c'est tout. Le crime était les 300 000 travailleurs forcés de Daimler-Benz qui se mariaient avec l'aéronautique française... et on imposait la loi du silence sur la collaboration.

Le 13 juillet 2000 j'ai déposé une protestation pour non-sincérité de la "documentation générale" à la DGCCRF.

"Troll" ? realy ?

[ChristiaanJ]

Troll alert !

[Volume]

What I always was wondering about and what is related to the "magical outcome scenario #1": Why does Concorde reach V1 (or the "point of no return") already after less than 1/3 of the available runway ? I would always believe that the brakes (assuming they are intact) can decelerate the aircraft much more efficciently (especially on a dry runway with grooves) than 4 olympus engines with reheat (one of them limited in power) could accelerate it. I would always expect v1 to be reached after using half of the runway length.
Taking into account that the crew was aware of problems well before half of the runway and even less than 1/3 from massive obstacles ahead, why would they not be able to stop the plane in due distance?
(I fully agree with the former post, that stopping a fully fueled aircraft on fire with its long leg landing gear would have probably not saved more than a handfull of lives of those in the forward cabin, if at all. Especially if you compare it to the size of the fuel leak in the Air China 737 accident in Okinawa and the impressive fire destroying the aicraft)

[ChristiaanJ]

What I always was wondering about: Why does Concorde reach V1 (or the "point of no return") already after less than 1/3 of the available runway ? I would always believe that the brakes (assuming they are intact) can decelerate the aircraft much more efficciently (especially on a dry runway with grooves) than 4 olympus engines with reheat (one of them limited in power) could accelerate it. I would always expect v1 to be reached after using half of the runway length.
Where did you get your figures from ?
I'd have to pull up the BEA report, get out the performance manual, and do some back-of-the-envelope figuring ... did you already do that?

One minor detail (and probably not relevant) when comparing 'engines' and 'brakes', is that it was not possible to 'hold' the aircraft 'on the brakes' at full power plus reheat.

CJ

[Volume]

Where did you get your figures from ?From Annexe 12 to the BEA report. This is the satellite picture of CDG with all the important points (lift off, crash site...) and the point where the FO was calling out V1. This point is at less than 1/3 of the runway length.

it was not possible to 'hold' the aircraft 'on the brakes' at full power plus reheat.This of course does already explain a lot...

[Emdat]

That is so great information.

[Emdat]

Nice posts.

[NineEighteen]

Fifteen years gone in a flash. RIP to the one hundred and thirteen victims and of course the magnificent aeroplanes.