AF Concorde Accident-another view

[TAT Probe]

I recently received the following by Email from an industry contact in the US. Apart from the obvious reaction that this is just another item of anti-European technology bias, I wondered if anyone could confirm any of the allegations raised in the item. It is as follows:-

Subject: New Results about last year's Concorde Crash

A completely different perspective on the crash, by looking at the whole picture by an unknown NTSB inspector
**************************************************** We all also know that the Concorde crashed because it hit a metal strip dropped from a CAL DC10 that departed from the runway just prior to the Concorde's departure. Right? Wrong!

I prefer the Swiss cheese theory of accidents where the holes line up in the various barriers to prevent accidents. When they do line up there is an accident, over the Boeing chain of events, but whichever you subscribe to this will follow either.

Hole number one: The airplane had been in maintenance prior to this flight and maintenance kinda sorta forgot to put a critical spacer in the LMLG (left main landing gear) truck. (we will get to this later).

Hole number two: The airplane is sitting at the gate. It is a few pounds over gross, roughly 16,000 lbs. and the CG is near the aft limit.

Hole number three: The V1 speed for the weight is 199K. Now we get to the runway and off we go. As the airplane accelerates it begins pulling to the left. Oh yes, the spacer was there to keep the trucks from swiveling. (V1 is called Decision Speed. Above this speed it may not be possible to stop the aircraft on the runway in the event of a rejected takeoff (RTO.))

Hole number four: As they barrel down the runway the airplane's LMLG hits a runway edge light stantion. Guess where the stantion goes? You got it...right into the left fuel cell and punctures it and starts a fire. Serious, but salvageable. Now you ask, "Why didn't the captain just abort the takeoff?"

Hole number five: Sitting on a taxiway waiting to cross the runway is a 747 with the French president and his wife aboard. The captain now has a choice. He can try to abort and perhaps plow into the 747 or he can try to fly.

Hole number six: He decides to fly and rotates at 188 knots, 11 knots below V1.

Hole number seven: So now you are having a really bad hair day. You are in a burning, over gross airplane with the CG going farther aft by the second because of the fuel loss, you are behind the power curve big time. What can make the day worse? (By the way, for all intents and purposes, they were already dead before the next, "Ah sh*t").

Hole number eight: The friendly, helpful flight engineer, on his own, without consulting the captain, decides to shut down an engine he THOUGHT was on fire.

Now your bad day really is as bad as it gets: the airplane is on fire, it's behind the power curve anyway and now you have an engine shut down when you are below VMCG Air. The airplane rolls over on its back and crashes into a hotel. (VMCG, which stands for Minimum Control indicated airspeed - Ground, is the minimum speed (Velocity) at which the pilot can maintain directional control of the aircraft with one engine suddenly becoming inoperative during the takeoff roll, with the use of aerodynamic controls only).

Now you know why we don't fall in love with theories or jump to conclusions based on initial assessments. Blaming the accident on the CAL DC-10 was the easy way out.

That makes it someone else's fault.

****************************************************
I have no information about the apparent author of this (an "NTSB" inspector, allegedly.)

Any evidence for any of the points he raises?

[lomapaseo]

The Swiss cheese or Reason model can be a useful tool if one has any idea of the probable number of holes that exist in any layer.

By the time you take the already established historical independent probabilities for each of the factors that are cited in this unauthored "a friend told me" piece of speculation you would have to conclude that the chance combination of aligning all these holes was so astronomical that it would never happen again so why even consider an airworthiness action.

Of course there has already been much discussion and factual evidence that already disproves some of these individual slices of fancy cheese so I don't think that further specific accident cause discussion along these lines is warranted.

[spagiola]

All of these issues have been discussed here quite heavily. See
Concorde Accident Part II (http://www.pprune.org/forums/showthread.php?s=&threadid=3851) for just one of the threads.

[Flap 5]

TAT has a point. You have to ask that why at each stage of this unfolding disaster someone didn't stay 'stop things are going wrong'. Nobody is willing to lose face.

Even after the accident the French were saying that it had to be a fundemental flaw with the aircraft and were angry that BA didn't ground their aircraft immediately. To the French that implied that the French had done something wrong when clearly (in their view) there must be a problem with all Concorde aircraft. BA were therefore forced to ground their aircraft to reduce the French loss of face.

As usual when confronted by political pressure the British government caved in. So when are the French going to start buying British beef then?

[NW1]

TAT,

Agree with others in this thread (its been discussed before, and the "unknown source" is wrong on several counts).

Just to clarify some of the points raised: (please feel free to copy this to your industry source)

<< Now you ask, "Why didn't the captain just abort the takeoff?" >>
The reason why the Captain didn't abandon the takeoff was that at and before V1 there were absolutely no indications of anything amiss, so the question is why should he have aborted the takeoff?

<<As they barrel down the runway the airplane's LMLG hits a runway edge light stantion. Guess where the stantion goes? You got it...right into the left fuel cell and punctures it and starts a fire. Serious, but salvageable.>>

The markings on the runway left a very clear record of the position and timing of the leak and fire. There was a massive area of unburned fuel on the runway centreline and a long sooted area left by the fire which started one second after the leak - again right on the runway centreline and well before the damaged lights.
This scorching showed the path gradually verring left as directional control became more of a problem (not surprising with a massively damaged wheel truck), but the fire was already well established. There *were* damaged runway edge lights, but the aircraft was almost airborne when it contacted these, and the tank was definately not "punctured" by *anything*: the hole was caused by a pressure wave inside the tank pushing tank and aircraft skin outwards. I doubt that one would base one's decision not to impale a 747 on whether it held the President or not. He was well beyond V1, almost at Vr, and faced with losing direction control and colliding with another aircraft. He started to rotate.

The tyre debris included a very large piece with a cut which matched the shape of the titanium strip *exactly* - that tyre was definately destroyed by the strip - not a question of passing the buck, but statment of fact. No strip, no accident.

The final issue was one of Vzrc, not Vmca (this "NTSB inspector" obviously doesn't understand Concorde aerodynamics - that is not a sin, but pontificating on something he shows he doesn't fully understand denies him credibility). Once below Vzrc (the zero rate of climb speed) the angle of attack increased beyond all limits and control was lost. It is worth pointing out that Concorde certification required better engine-out performance than conventional types, in fact a Concorde on 3 engines at max AUW needs to roll on 15 degrees of bank before its climb gradient reduces to that of a conventional type in the same situation. The aircraft was fatally damaged by a massive fuel leak and fire - no crew action could have saved her, or any aircraft in a similar predicament.

[edited to correct typo....!]

[TAT Probe]

Thank you NW1 for your illuminating reply. I had not wished to give this so-called "NTSB man's" views any credence, but I did want to bounce something back across to my contact to refute the arguments. Your post will do nicely!

There always seems to be some Smart*ss willing to go into speculation on any accident, and we see it constantly in threads on Pprune. I didn't want to give any credence to such views, only to get some information to counter this opinion.

Thanks also to those who pointed me to the original thread.

[NW1]

TAT - You're welcome.

Agree re. uninformed speculation, particularly when you know it to be incorrect. There was a letter published in Scientific American magazine some months ago by an MD11 (from memory) F/O who obviously had a grudge against Concorde and went sounding off with all sorts of BS about the SST and her performance certification.

Without boring you with details, it was all 100% wrong (the funniest bit being his assertion that at V2 conventional types are certified to climb away having suffered 2 engine failures - maybe gravity is weaker on his planet?). I sent a carefully worded non-agressive letter countering his points one by one, but SciAm chose to leave the uncorroborated mis-information unchallenged. What did annoy me was the pseudo-credibility afforded his letter by his quoted credentials as a current airline pilot. Shame, really - he really ought to know better.

[HugMonster]

Agreed, NW1.

I saw a website recently which excoriated the ATR for being less than airworthy (it called it dangerous) based solely on the accident at Roselawn, Indiana.

It failed to mention that, during the 45 minutes prior to the accident, the captain spent nearly twenty minutes in the back chatting up one of the cabin crew whilst the aircraft was in the hold in heavy icing conditions, with an FO of very limited experience flying the aircraft on his own.

It failed to mention that the crew broke all the ATR-specified methods of handling.

It failed to mention that for at least part of the remainder of the time a cabin crew member was on the flight deck talking to the pilots.

It failed to mention that during a period of about 37 minutes (if my memory serves me right) the pitch trim whooler went off with the autopilot in - sure sign the aircraft was having trouble keeping itself in trim but with no action or comment on the part of the crew.

It also failed to mention that any other aircraft, in heavy icing and mishandled by a crew who were more interested in getting off with the girls down the back than they were in flying the machine, would have had severe difficulty.

It failed to mention that there was no attempt by the crew to request a routing or altitude that would get them out of heavy icing conditions.

It also failed to mention that, despite the accident being due largely to thoroughly unprofessional and complacent (verging on incompetent) crew, ATR made several changes to the aircraft and its deicing, and conducted a demonstration of the aircraft's ability to accrete massive quantities of ice and stay airborne.

Yet the attitude in the USA is that this is a dangerous aircraft.

And this article is the accepted truth in the USA about the ATR, which is, in my experience, a very reliable, safe, comfortable and quiet aircraft, and a delight to fly.

One wonders whether there might be fears in the USA about other people building aircraft in competition with them? One remembers more than one campaign against Concorde over the pond...

[norodnik]

It is stange that these facts come out at this time. The message you (TAT_PROBE) have posted is extremely similar to an article posted last year which goes through similar things.

Alas, a lot of what is in your (NTSB) post is true. As usua,l Air-Chance and the French authorities have covered everything up to prevent the shaming of the national ariline.

In addition to the points raised.

The Ill-fated aircraft also took off with a tail-wind component.

There are "un-explained" tyre marks which are almost certainly as a result of the spacer causing the gear to swivel and therefore explains the crab sidewards towards the edge of the runway. (not to mention the braking effect)

The plane was well-over weight and outside of its operating limits.

Finally, the aircraft would never have got to the DC10 metal stip if it had taken off normaly. Like most accidents, it was just another contributing factor which made a bad situation worse.

Concorde should never have been grounded, Air France were clearly negligent, Captain Marty more so.

[Send Clowns]

I understand (my source used to be an Air France Flight Engineer, his source is a friend in the company) that the fuel tanks were overfilled as well, and the tank hit was actually completely full. Had this not been the case the shock wave would have been largely absorbed by the air in the top of the tank, the top surface would have remained intact and even if the lower surface had punctured (not certain, as it would have had slightly more flex) the leak would have been far less destructive. Very unfortunate.

In the suggestions of the French lying about their illegal operations and laying the complete blame elsewhere, perhaps echos of the crash of that other SST, the TU-144?

[Fat Tony]

Quote:<<Now your bad day really is as bad as it gets: the airplane is on fire, it's behind the power curve anyway and now you have an engine shut down when you are below VMCG Air. The airplane rolls over on its back and crashes into a hotel. (VMCG, which stands for Minimum Control indicated airspeed - Ground, is the minimum speed (Velocity) at which the pilot can maintain directional control of the aircraft with one engine suddenly becoming inoperative during the takeoff roll, with the use of aerodynamic controls only).>>


Call me pedantic, but VMCG Air is not a term I've heard before...
VMCA and VMCG: YES, but VMCG Air: NO.:cool:

[TowerDog]

VMCG = G is for ground.
VMCA = A is for air..(Airborne)

Hug: About the ATR: Well, what about the Italians: Did they not have a similar crash with their ATR about the same time?

If the design was good, why was the airplane modified after more testing in icing conditons?

What about the business of aileron reversal with the wing iced up?

Never flown the thing, but have read some reports about it, including a book about the Roselawn accident.
Ya read that book Hug?

[Captain Stable]

No aircraft design is that good that improvements cannot be made in the light of any incident experience. I understand that the boots were altered to trail further back over the upper surface of the wing.

Also, no design is good enough to remain in the air if it is not handled in accordance with the manufacturer's procedures.

[NW1]

Norodnik:
The Ill-fated aircraft also took off with a tail-wind component.
It is true that the tower gave, at one stage, a wind report which gave a tail-wind, but post-accident analysis showed (using recorded track, g/s, heading and tas) that the wind at the aircraft was practically zero at lift-off. Whatever the procedural issues of accepting the tower reported wind are - since the a/c was not experiencing a tailwind at liftoff, it was not a factor in the accident.
There are "un-explained" tyre marks which are almost certainly as a result of the spacer causing the gear to swivel and therefore explains the crab sidewards towards the edge of the runway.
The initial fuel leak (unburned fuel stain on the centreline) and the track of the scorch / soot marks starting on the centreline and then curving left clearly show that the centreline deviation did not occur until the encounter with the metal strip, the massive left gear damage, and the unique chain of events immediately thereafter which led to the massive tank rupture and ignition of the leak. Your assumption and "almost certainly" qualifier are easy comments to make from the sidelines without having to prove yourself.
Finally, the aircraft would never have got to the DC10 metal stip if it had taken off normaly
How so? The takeoff was "normal" until the strip was encountered. It would have never struck the strip if its track had been 1 metre to the left or right. It would never have got to the strip if it had used a different runway. The encounter with the strip was unfortunate happenstance, and it is facile to come up with "ifs" which have the aircraft missing it. "If" the strip had been lying in any other orientation, the tyre would have rolled harmlessly over it - and that is nobody's fault.
Concorde should never have been grounded
Agreed
Air France were clearly negligent
An uninformed and probably libellous comment.
Captain Marty more so.
...as above and add utterly beneath contempt from behind the cloak of anonymity. It took a lot of self-control to restrict my language on that one - I hope you can deduce what I'd really like to say about that comment.

Send Clowns:
I understand (my source used to be an Air France Flight Engineer, his source is a friend in the company) that the fuel tanks were overfilled as well,
There are manufacturer approved procedures to increase fuel loading to above the nominal "full" levels. This adds a tiny amount (usually about 12-1500 kgs, or about 1.5% of the total fuel load). It is a documented, tested and fully approved procedure - the Concorde's fuel tank venting system works as published even when this "extra" fuel is loaded. Many commentators with little knowlege of the Concorde fuel system have heard vaguely of this procedure and mis-quoted it - like yourself - incorrectly implying incorrectly fuelled tanks.
Had this not been the case the shock wave would have been largely absorbed by the air in the top of the tank, the top surface would have remained intact and even if the lower surface had punctured (not certain, as it would have had slightly more flex) the leak would have been far less destructive. Very unfortunate.
The tank top surface did remain intact. How do you propose your fuelling idea would afford the lower surface "more flex"?? How would the leak in your example be "far less destructive"? So what do you suggest - all jet transports now restrict themselves to 80% tank capacity? What physical evidence and fluid dynamics calculations have you used to make this assertion? :-
The Concorde tank vent system provides air for fuel surge and correct tank pressurisation - the hydraulic ram effect still occurred on the accident aircraft which would indicate that the mechanics and dynamics of the tyre failure, not tank capacity, was the cause. The new Michelin tyre is highly advanced, far more resistant to failure - and when pushed to failure does so in much smaller, confetti-like pieces.

All the links in the chain have been addressed - any other factors like weather, crew procedures etc. although they exist, are merely diversion from these main causal links and have no bearing on the outcome and an infintessimally improbable chain of events has now been broken at every link.

The crew of 'SC can rest in peace knowing that nothing they could have done would have saved the flight - and also that everything has been done to assure that it will not happen again.

[TowerDog]

Good posting NW1.

But, is it not a fact that the AF Concorde took off over-weight and is it not also a fact that the F/E did shut down an engine without the captain commanding such an action?

One would think that either of the above events, if indeed they did occur, would be enough to down a crippled airplane, and much more so both...?

[norodnik]

NW1

it is clear from your reply that you tend to believe the report submitted by the BEA. The BEA in the past have been heavily criticised for concluding things when all evidence points to other reasons. You can make your own assumptions as to why this may be but most people know the reasons.

In replying to your comments:

The wind direction before takeoff was predominantly from behind the aircraft. With an overweight aircraft already outside limits, do you think its a good idea to hope it doesn't change during the roll or would you rather take the safe option and taxi down the other end.

THE BEA contend that the accelration was normal, however subsequent calculations indicate otherwise. BTSC should have been in the air before the strip.

What about the type marks on the runway, look at the pictures. They are clealy made by locked tyres, not burst ones. Why would the tyres lock, why would the aircraft veer to the left when normally you can compensate for drift or deal with engine failure.

Let me know next time you are in the front seat because I definitely don't want to be anywhere near you.

If you think taking to the air in an aircraft that is outside its design limits (even the BEA says CofG was 54.2), overweight, likely unfavourable winds etc then fine. Please let me know why you think these actions were reasonable.

Finally, Air France is surely responsible for the maintenance of its aircraft and training of its crews. The aircraft had defects. The F/E did not follow procedures and so on. Please also indicate what word is applicable to these things. Maybe you had the word unfortunate in mind ??

[NW1]

norodnik,

<<The wind direction before takeoff was predominantly from behind the aircraft. With an overweight aircraft already outside limits, do you think its a good idea to hope it doesn't change during the roll or would you rather take the safe option and taxi down the other end. >>

Please try to read my posting again. Note that I did not make a subjective critique of crew actions and nor will I now - I did not say what I think was or what was not a good idea. I merely stated what is known (read it again) and unlike you did not extrapolate, guess, and condemn individuals on the presumption that you know more about the aircraft and the accident from your armchair than the investigators. All I did say was that the facts as known indicate that the accident would have happened with any wind and at any weight, and that therefore the crew actions did not cause the accident.

<<What about the type marks on the runway, look at the pictures. They are clealy made by locked tyres, not burst ones. Why would the tyres lock, why would the aircraft veer to the left when normally you can compensate for drift or deal with engine failure. >>

You keep saying (ignoring the typos) "clearly" X happened and "clearly" Y error was committed, but how can you say that an undercarriage truck damaged in a way the tyre manufactures described themselves as "unique" would behave in any particular way - particularly as you weren't on the investigation team? And how can you make deductions by comparing this event with a "normal" engine failure? You make extrapolations and cast assertions beyond the facts available to you. Look at what I said: the centreline deviation only started after the tyre destruction / fuel leak / fuel fire event. That's all I said: my intention was to state fact and avoid your tendancy to publish conspiracy theories prefixed with "clearly.....".

<<Let me know next time you are in the front seat because I definitely don't want to be anywhere near you.

If you think taking to the air in an aircraft that is outside its design limits (even the BEA says CofG was 54.2), overweight, likely unfavourable winds etc then fine. Please let me know why you think these actions were reasonable. >>

[footnote: if you knew the approved Concorde CG tolerances, you would know that 54.2% is acceptable. Sorry to dissappoint.]
Again - please read my posting. <<If you think ....>> Do not presume to pass judgment on my own professional ability based on something you tell me I think. For the record I think no such thing. Your need for aggression and accusation (both toward me and 'SC's crew) seems to be greater than the need to stick to the facts and to actually read what I wrote. What I said was that the aircraft was doomed by factors outside the crew's control: the encounter with the metal strip which terminated in the massive fire via a chain of very improbable links. The fire was destroying aircraft structure and systems at a rate which meant the number of engines operating, aircraft weight and surface wind affected only the time left before the inevitable.

Let me close by quoting from my own posting, which hopefully will help you understand what I was trying to say:
any other factors like weather, crew procedures etc. although they exist, are merely diversion from these main causal links and have no bearing on the outcome and an infintessimally improbable chain of events has now been broken at every link.

[GlueBall]

NW1 says: "...no crew action could have saved her, or any aircraft in a similar predicament."

Well, sir, I may go down, but I'll be kicking. I would hang on to whatever "control" I have to stay alive and to effect a controlled crash if necessary.

It's a tough, almost unthinkable decision to deliberately crash land a heavy jet, much less an SST. But when you're running out of airspeed there's nothing else to do but to put the bird down before it puts you down.

Our simulator training "mind set" always has us getting the airplane safely back unto a long pavement somewhere, eh? But just maybe some people would have survived a "controlled crash" straight ahead into a farmer's field if Marty hadn't attempted to stay aloft and to stretch the flight to Le Bourget just 7 miles ahead. The copilot had warned him three times about decaying airspeed.

At less than the height of the control tower, at only 200 feet, with gear jammed in the down position, multiple engine failures, and decreasing airspeed, good survival instinct would have dictated to put the airplane down now ...before it stalls.

[norodnik]

NW1

I am sorry you mistake my passion for aggression, and typing is not exactly my strong point.

However, I am perplexed by your defense of the crew.

You state that the crew actions did not directly cause the accident. But it is clear that their actions left them with few alternatives.

Who is responsible for the weight of the aircraft ?
Who is responsible for ensuring that the aircraft is within operational limits ?
We all expect that pilots take no unreasonable risks and Captain Marty therefore either didn't think the wind was an issue or decided he could get away with it.

I agree totally that if the other events hadn't happened he MAY have got away with it. However, how many crashes would there be if every takeoff was subject to such risks. The pilot is expected to be professional in all respects, if other things happen then one hopes he can deal with them in isolation and not have to deal with other problems which he himself caused.

Regarding the CofG. My father was involved in the development of Concorde, has written books, articles and engineering papers on everything from powered flying controls to supersonic flight. He also knows many of the past and present pilots of Concorde. I asked him about the CofG issue and he told me it was once limited to 53.5 and subsequently raised to 54% on account of the need for increased range.

Now, his facts may be out of date but from the people I have consulted they seem to hold true. Perhaps you can refer me to the ammended limits and under which conditions they are considered safe.

Finally, to close off, and in refering to my first post on negligence. Do you consider that Captain Marty was in no way to blame for contributing to the accident