CONCORDE ACCIDENT - PART 2

[BEagle]

At the request of Capt PPRuNe, I have edited the list of questions which Jackonicko and I had posted in my earlier 'Concorde Discord' thread (now deleted). Please note that these questions are not intended to be in any way xenophobic, it is merely the truth which is being sought - OK??

Let's get back to the whole point of the thread:

1. RIP Capt Marty, his crew and passengers who died during an heroic attempt to make a forced landing at Le Bourget following critical failures suffered by F-BTSC.

2. Whilst the principal cause appears to have been tyre failure leading to subsequent hydrostatic shock rupturing a fuel tank and an external ignition source causing the resulting severe fire, are there other areas of the aircraft's operation which merit closer scrutiny? Specifically:

a. Was the ac over its maximum certified structural take-off weight when it began its take-off roll?

b. Was the 8kt tailwind sufficient to reduce RTOW to a figure below that of ATOW?

c. Are current AF SOPs adequate to prevent uncommanded engine shut downs at critical stages of flight?

d. Is current AF CRM training adequate to prevent an aircraft taking-off outside scheduled performance limits?

e. Are CdeG runway inspection standards now adequate?

f. How far aft was the C of G (the Observer said more than the BEA), and what effect would this have had?

g. What was the effect of the missing spacer on the undercarriage?

h. What would be the likely impact of taking off one tonne above structural weight, or six tonnes above RTOW? How reasonable is it to wonder whether this would have exacerbated or even caused the tyre blow-out?

i. Have we been well served by the BEA and DGAC with their report and our own CAA who simply rubber-stamped it?

[Jolly Tall]

Although I don't have any additional content to add to this thread, it is to the good that it has been resurrected - undoubtedly one of the most interesting in recent times, and the unresolved issues it has featured need to be kept alive until they have been satisfactorily explained.

[edited for clarity]

[ 28 August 2001: Message edited by: Jolly Tall ]

[Jackonicko]

In addition to being overweight, was the aircraft also 'overfuelled'? Was the fullness of the tanks a contributory factor to the 'explosiveness' with which hydrostatic shock caused the tank to burst?

Did the crew carry out their preflight duties adequately?

Did the crew recalculate weights, distances and speeds when informed of the change of runway? How seriously should we take it if they didn't?

Can anyone justify taking off downwind in these circumstances - and from that runway rather than the other - apart from noise abatement?

Can anyone quantify or even guesstimate the likely affects of being 1 or 6 tonnes overweight and behind the aft c of g limit on tyre performance, acceleration, and control speed, and on the speed at which departure became inevitable?

How critical was the piece of FOD ( a flat bit of metal) in causing the tyres to burst?

Would they have got away with it without an ignition source for the venting fuel?

Can anyone confirm, quantify or conclusively deny the early suggestions that there was a marked difference in BA and AF tyre use practises (retreads or not, no.s of landings allowed before replacement, etc.)?

What were the affects of the tailwind?

When the accident happened, much was made of a recent repair to a thrust reverser cowl. Which engine was that, and did it have any bearing on the accident, or on the crews response to the situation as it unfolded?

[ 29 August 2001: Message edited by: Jackonicko ]

[GlueBall]

Irrespective of CG, overweight, tailwind, tire failure, engine failure, fire....

The fact was that the airplane was airborne at 200 feet at sufficient airspeed with enough flight control authority to effect a controlled crash landing straight ahead into an open field. No other option!

What we can learn from this accident is what to do when faced with similar unimaginable inflight terror.

First we must overcome the limitations of simulator training and its "mind set" of always being able to return a crippled jet to an airport.

Secondly, we must apply our survival instincts and act accordingly.

Marty, perhaps overcome from sensory overload with bells, chimes, crewmember prompts and ATC talk, had hesitated. Despite three urgent reminders from his F/O about airspeed decay, Marty, with Le Bourget in sight, continued to extract performance from his jet.

The airspeed indicator should have triggered the captain's survival instinct; immediately lower the nose and put the jet down. Right now. Such an instinctive decision requires neither time nor thought, only technique in effecting a high speed soft field crash landing.

What every single engine student pilot learns on day One: If the engine quits right after takeoff, don't even think about turning; land straight ahead!

[Wino]

An off airfield crash is not a surviveable option in this scenario. In fact there have been precious few examples of off airfield landings of jets that worked out. The only ones that I can think of involved a total absense of fuel on the aircraft.

200,000lbs of fuel at 200 kts is a HUGE fireball. If you don't impact in the immediate, I mean IMMEDIATE vicinity of the field firestation, you haven't got a chance.

Had they put the aircraft down strait ahead in a field fully fueled, the result would have been the same, all on board dead.

Furthermore, there is no way they could have known where the fire was. Aluminum degregrades VERY rapidly when heated, I suspect the holes in the plane were rapidly getting larger. If a fuel tank is streaming fuel and on fire, I hate to say it, but its gonna end badly. The only hope is to land on the doorstep of crash fire and rescue.

Also, landing an airliner in dirt is the worst possible scenario. They simply aren't stressed for it. That is why when the landing gear is hung up and you can't get it down you belly land on the concrete, not the dirt next to the concrete. This is because the aircraft will slide around on the concrete doing less structural damage then in the dirt where it will tend to dig in. Airplane digs in and tumbles, initial impact may have been controlled, but the second one won't be.

Don't believe me? Its a mandatory write up and inspection ANY time an airliner leaves the concrete, even taxing at 5 kts because of the stresses on the uncarriage. Yes, I know there are exceptions for the 727/737s with the gravel kit, but those aircraft are designed for it.

As to the climb to 200 feet. I suspect that he was trying to get just high enough to see the field, at less that 100 feet you would be ontop of the field before you could aquire it visually...


Cheers
Wino

[ 29 August 2001: Message edited by: Wino ]

[exeng]

Beagle,

Capt Marty (RIP) was between a rock and a hard place. I most sincerely hope that I never have to face the scenario that he and his crew did. I'd like to state that we are now looking at this horrific situation with 20/20 hindsight. And we are dissecting the situation as such. It is my belief that Captain Marty was attempting his 'approach' into Le Bourget knowing that he had at 'catastophic' situation on his hands. Unknown to him it would seem that the F/E had shut down an engine that was producing power. (There was a fire warning on that engine.) Normal SOP's would seem to dictate that an engine would only be shutdown when ordered by the Captain, but there may have been some divergence from SOP's in this case.

Capt. Marty and his crew would have been trained for (in the case of Perf 'A' A/C the loss of one engine on T/O). To the best of my knowledge there is no training for losing two engines at max weight, with the gear failing to retract, and a raging fire which has (unknown and obviously untested) effects
on the performance of the A/C.

a)Was the ac over its maximum certified structural take-off weight when it began its take-off roll? No it wasn't. But it would seem that it taxied out overweight.

b. Was the 8kt tailwind sufficient to reduce RTOW to a figure below that of ATOW?

This one did shock me when I first heard about it, but I am told (by sources that have a British origin and all that) that by all reports the A/C was within the limits. This is becauase the authorities have 'apparently' looked at the actual wind that prevailed at various locations at CDG at the time.

c. Are current AF SOPs adequate to prevent uncommanded engine shut downs at critical stages of flight?

I don't know the answer to that question, but I would ask you if any airlines SOP's are adequate. Unfortunately we are dealing with very frail human beings here.

d. Is current AF CRM training adequate to prevent an aircraft taking-off outside scheduled performance limits?

I can't answer that question, but I would ask the same question of any other airline.

e. Are CdeG runway inspection standards now adequate.

Yes I believe they are, and they 'probably' were adequate at the time. (How did LHR's differ at that time?)

f. How far aft was the C of G (the Observer said more than the BEA), and what effect would this have had?

Insignificant, or so I'm told.

g. What was the effect of the missing spacer on the undercarriage?

It is my personal belief that this may have had a significant impact on the chain of events that led to the accident.

h. What would be the likely impact of taking off one tonne above structural weight, or six tonnes above RTOW? How reasonable is it to wonder whether this would have exacerbated or even caused the tyre blow-out?

Clearly taxing out in excess of the max structural weight (by one tonne) cannot be condoned but I do not believe it to be a significant contributury factor in this case.

The RTOW case would perhaps be answered by question 'a' above.


i. Have we been well served by the BEA and DGAC with their report and our own CAA who simply rubber-stamped it?

I really don't know the answer to that one either mate. The cynic in me says that there is a chance of a 'whitewash'. I do however truly believe that the CAA would only allow re-certification if they believed the A/C to be 'safe'. And, by the way, I believe the A/C to be safe and would fly on it tommorrow!


May I say that I believe that Captain Marty performed exceptionally well under the apalling circunstances. Let us hope that none of us fellow airman find ourselves in a situation similar to Captain Marty's.

As an aside I truly hope that none of the families of the crew involved in this terrible accident have access to PPRuNE.

Out of interest I have never, ever, been involved with the operation of Concorde. But I know a few people who are.

By the way I'm with 'Sick Squid' on his defense of the post by 'wallabie'. You could say that I'm not too keen on 'vultures' picking on the remains of carcasses.


Regards
Exeng

[Jackonicko]

Wino,

I believe that you may be being unduly pessimistic about the survivability of 'off runway' forced landings or crash landings, and wonder whether you have been unduly influenced by the fact that a belly landing on tarmac may cause less (and less expensive) damage than a gear-down landing on 'dirt'. Bear in mind that Concorde has no underwing engine pods to dig in, and look at how often our expectations are confounded during force-landings - look at that RAF Nimrod (Comet) which pulled off a successful ditching in which the only injuries were a broken thumb and kerosene ingestion related inflammation of one chap's throat. With the severity of the fire however, it naturally didn't look good....

Exeng,

You say: "Clearly taxing out in excess of the max structural weight (by one tonne) cannot be condoned but I do not believe it to be a significant contributury factor in this case." I'm pleased you 'don't believe', but are you so sure that it didn't cause or exacerbate the blow-out? That it didn't provoke the veering off the runway by putting extra stress on the gear with its missing spacer? Can we even be convinced that the over-stressed gear didn't generate the ignition source?

And had he been underweight, how much more likely would the aircraft have been to reach a more sustainable speed, or establish a better rate of climb? What difference would it have made to the speed at which the pilot lost control?

And was the extra tonne (or five tonnes) all fuel? If so, did filling the tanks that tight make their failure more likely when subject to tyre impact?

I don't think it's ever acceptable to lose a human life. The death of even the least able, most cack-handed pilot will always be a tragic human loss. And I think Captain Marty was obviously a great character (he inspired great affection and loyalty in those who knew him, clearly), but as long as people aren't making highly personal attacks on him, or his engineer, or his co-pilot, then I think that on balance, it's just about acceptable to ask questions about the crew's actions and about human factors. I wouldn't like it if I was tyhe grieving widow, I'll admit, but nor would I like it if I were the widow of one of the passengers, and I knew that airline professionals were inhibited from trying to learn lessons by their reluctance to 'disturb' even the memory of one of their own - and that's how it could look.

Brave fellow, top bloke, obviously, but perhaps not without faults and failings - like every one of us. The question is, were those inevitable human frailties relevant this time? They do seem to have been a factor.

[wallabie]

"By the way I'm with 'Sick Squid' on his defense of the post by 'wallabie'. You could say that I'm not too keen on 'vultures' picking on the remains of carcasses. "

Thanks mate.

[cosmo kramer]

[quote]Jackonicko
Wino,
I believe that you may be being unduly pessimistic about the survivability of 'off runway' forced landings or crash landings, and wonder whether you...[/qoute]

Jackonicko, it seems to me you are not really looking for answers, but rather seeks affirmation to the points of which you have already made up your mind. :confused:

Concorde is not a Cessna 152. You don't "stretch the glide" (in your words) because it's not gliding. If you get a ground proximity warning "pull up" in a jet you pull back until stickshacker onset, ease a bit, and keep it there until clear of terrain. Doesn't that tell you anything?

The captain did a great job in my opinion (atleast once airborne - and the rest is speculation) and had great survival instict. He did the right thing according to the CVR, trying to make Le Bourget.

[Jackonicko]

Cosmo,

I'm big enough to admit I haven't got a clue! Could he have landed? Dunno? But I'm interested in people's views, yours, and people who've flown similar types. And look at the responses - Wino, a twin-jet F/O thinks "no way", while Glueball, a wide-body Captain isn't so pessimistic.

But what I haven't done is make up my mind, on that or any other issue. What a pity that your selective quote left out the other part of my sentance - namely: "With the severity of the fire however, it naturally didn't look good...."

But let's not get drawn into the if he'd gone for a forced landing would it have been survivable road again. The answer has to be maybe, maybe not, and to be honest, there may be few lessons to learn here. There are other, more germane questions being asked however - or perhaps you think I've made up my mind on those too?

Should we perhaps have a separate, 'slag off' and kick the journo thread, and leave this one clear for asking and attempting to answer the outstanding questions? Alternatively, if you just want to get some bile off your chest, then drop me an E-mail and save some band-width.

[spagiola]

It seems to me there's second-guessing, and then there's second-guessing.

I think it's perfectly legitimate to ask whether the Concorde taxied out and/or began its takeoff roll overweight, and why the crew didn't switch runway when the wind shifted. These were all decisions the crew took calmly and deliberately. There are procedures and regulations to follow. If there are doubts, there is both time and the means to resolve them.

Once in the air, on fire, too slow, claxons blaring, I find it a little less legitimate to argue about whether every split-second decision was right or not. Should the crew have tried to put down the airplane at once? Given that we know the outcome of not doing so, it's easy to say it would have been worth a try. But certainly there's enough uncertainty about the likely success of such a maneuver in a high-weight, high-speed jet loaded with fuel and already on fire. With Le Bourget so close, with a nice long runway, fire services, etc, that's a gamble that I can see myself making. It doesn't even require a 180 turn, just a fairly shallow turn, into the problem engines.

So I say, let's by all means examine very carefully the events and decisions that led that Concorde to have to take off on fire, including technical issues (fuel tank design, tyres, etc), procedural (ADP runway inspections), operational (weight calculations, runway selection), and serendipitous (that metal FOD, and the 747 in the Concorde's path). And if does turn out that the crew made mistakes, let's not shy from criticizing the crew for any errors or rule violations they might have made. Great human being or not, when you take up some 100+ people, you accept a lot of responsibility. But let's end this rather sterile debate about whether attempting to reach Le Bourget was preferable to putting the aircraft down in a field. Even from the comfort of my living room, with time for reflection, analysis of available crash statistics, examination of photographs of the terrain, and all the other luxuries Marty and his crew lacked, there's enough doubt in my mind about either course of action as to make a decision difficult. In the pilot's seat, with the stick shaking, alarms blaring, and my own life and those of 110 other people in my care at stake? I'm not going to second-guess anyone in that situation.

Somewhere in between these two cases is the engine shutdown decision. Yes, it was under pressure, but it also (apparently) went against both SOPs and common consensus. SOPs are there for a reason, and a particularly important reason when they deal with emergencies. So I think it is legitimate to ask why this shutdown took place, and especially whether its a systemic problem of poor CRM training or habitual disregard of SOPs.

[Jackonicko]

In the brief interval between posting and coming back to say "Damn! there is something I've almost made my mind up about" came Spag's excellent and common-sense post.

Arguments about force-landings (to do or not, survivable or not, etc.) are sterile and time-wasteing. He's quite right.

But what I'd meant to come back and admit to was my growing belief (I've almost made my mind up!) that had the FE left the No.2 running, they might perhaps (peut etre for Wallabie) have made it - maybe even had a good chance of making it, but once that engine was hut down, tragedy was inevitable.

But I'm still not quite comfortable with that conclusion, but can't explain or work out why.

Maybe it's because however stupid the decision was, and however far it ran counter to the rules, proper CRM and all the rest, I find it hard to criticise the FE, sitting there with chaos exploding around him, with things going very badly awry, and with ATC telling him that they had a severe fire. Maybe the afterburner problem was at the front of his mind? Maybe he forgot his training (inexcusable, technically, but....) and thought that shutting down No.2 would make it all go away. But perhaps we can say "Yes, if that happened then he made a fatal mistake" and yet still do so with compassion, sensitivity and understanding and without condemning him for it? Calmly acknowledging what went wrong could save lives however, whereas brushing the error under the carpet could lead to more deaths in the future.

I suddenly see from Spag's post that he's a journo, too! But I'm not agreeing with him for that reason, I assure you all!

Spag! Do I know you? Who do you write and phot. for, matey? Do we have any clients or customers in common, I wonder?

[llamas]

Just a thought.

Captain Marty's decision - to attempt to make it to Le Bourget - is now being discussed in absolute terms - that his only choice should have been (insert favored selection here).

But those choices are all based on a balance of probabilities - they are not hard-and-fast, and the discussions of them here are being had by people who were not in his seat. He knew best what the a/c was doing, how it was responding, and so forth. And even his knowledge may have been imperfect, but what else was he to base his decisions upon?

As the Sioux City incident showed us, it is possible to snatch some measure of recovery from the very jaws of disaster.

And we should also not lose sight of the fact that, once he made his decision, subsequent failures (in machinery or crew) may have made it a poor one - in hindsight. But I've been in the cockpit of a Concorde, and I saw no crystal ball installed. What seemed like his best choice may have turned into his worst choice 30 seconds later, because of some other condition which he could not foresee and may not even have known about.

It's very easy to be dogmatic now, and say "well, he should have crash-landed it right there in a straight line, any other decision is moronic and shows that he was a crappy pilot." But it's pretty obvious from all the testimonials that he was, in fact, a very fine pilot.

Me, I'm just self-loading freight. But I think I want a PIC up at the sharp end who is flexible enough, in such a situation, to be able to consider his options, all of them unpalatable, and choose the one that he thinks, based on what he knows, is least likely to fry my sorry ass, and then try everything in his power to make it happen - and not simply say "well, statistically, the best thing to do is to crash land right now, so now we crash-land. That way, noone will be able to fault my good judgement at the inquiry."

The questions about equipment, take-off weight, FOD and all the rest, are an entirely different matter. Many of them were unknown and unknowable to the flight crew. But I think it's a very shabby deal to suggest tangentially, as some others have done, that the PIC made a poor decision about eg TOW, and that therefore all his other decisions were similarly poor.

JMHO

llater,

llamas

[GlueBall]

Wino & Cosmo:
Check out the result of this deliberate off airport, gear down, controlled crash landing in a farmer's field a few miles short of Orly airport. (Fire in lavatory, smoke in cabin).

SURVIVORS? Yes, including crew.

Click on it (http://www.airliners.net/open.file?id=168113)

[ 29 August 2001: Message edited by: GlueBall ]

[exeng]

Jackonicko,

You ask if I am 'sure' that taxying in excess of the max structural (by one tonne) didn't cause or exacerbate the blow out?

I stated that I did not believe it to be a significant contributory factor. I am not 'sure' about anything. One tonne over max structural amounts to approx 1/2% of max gross weight, so what do you think? There are other factors that 'may' lead to tyre failure; for example under inflation of the affected tyre or it's opposite tyre on a shared axle can have devastating consequences. I'm not suggesting that was the case here, but it may have been and we will never know.

The missing spacer would have had an effect, but it would be irresponsible of me to attempt to quantify that effect. It is unlikely that we will ever know with certainty the effect of that and many other factors in this accident. Human beings like to see answers in perfect black and white but aviation, in common with many other facets of life, turns out to be many shades of grey.

The tower reported a tailwind component but 'perhaps' there was other evidence to suggest to Capt. Marty and his crew that this was not the case. I have certainly been given wind reports from the tower at various airports worldwide that are at variance with my observation of a windsock or smoke. On most occasions I will discuss this with the other crew before departure but I do remember on one occasion just pointing at the windsock and smiling. The CVR will not record this. We will never know for 'sure', will we, exactly what the wind was.

I appreciate Jackonico that you wish to ensure airline professionals can learn lessons from this tragedy. I believe that they will.

My view on whether an 'off airfield' crash would have been survivable. For what it is worth I am with Wino on this one and believe the chances of surviving are very small indeed; hence my previous remark about Capt. Marty being between a rock and a hard place. Hindsight is the clearest of all so we now know that the final actions ended in tragedy. Perhaps landing straight ahead would have ended with a similar result. If so who amongst us here would now be asking, "Why didn't Capt. Marty attempt to land at Le Bourget?"


Regards
Exeng

[Wino]

Ahhh, Glueball.

I looked up your crash and low and behold,

> Accident Database > Accident Synopsis > 07111973

Date of Accident: 11 July 1973
Airline: Varig
Aircraft: Boeing 707-345C
Location: Paris, France (Orly Airport)
Registration: PP-VJZ
Previous Registrations: N9322S
Flight Number: 820
Fatalities: 123:134
MSN: 19106
Line Number: 683
Engine Manufacturer: Pratt & Whitney
Engine Model: JT3D-8B
Year of Delivery: 1968
Accident Description: The aircraft made a successful emergency landing after reporting fire in a rear lavatory, but 123 of the 134 passengers were overcome by smoke and carbon monoxide before the plane could be evacuated.


Now notice that 11 people out of 123 survived. Maybe more would have survived had crash fire and rescue been nearby it assist in the recovery of the people. In these cases the smoke in the cabin usually doesn't get out of control UNITLL THE DOORS ARE OPENED, and then the chimney effect takes off.

Another point, this is an aircraft that was LOW on gas and weight and even fully loaded had a much slower approach speed than a cocorde. Take the soiux city crash by comparison. Because they were able to crash inside the perimeter of the airport, almost half the people were saved through a combination of on scene medical and all the hospitals were perpared and double shifted for the incoming casualties.

If you don't crash at the airport you haven't got much of a chance.

Cheers
Wino

[cosmo kramer]

Thank you Wino. Where were you in the first thread? :D

Jackonicko, I'm not slagging you. Wheren't you the one that called me "stubborn or ..." (I presume I was to insert a stupid there?) - doesn't sound like you are much interested in any opinion that doesn't support yours :rolleyes: Anyway...

The fact is that you are being sceptical about certain actions the crew was making. However, on one hand you critise them for not adhering to procedures and on the other hand you blame them for not, in Glueball's words, overcome the limitations of simulator training and its "mind set" of always being able to return a crippled jet to an airport."

Always, always, always stick to procedures. It's like seatbelts. Some unlucky few might get caught in the seatbelt and die as a result BUT a lot more will be saved by using it. The point is that no pilot should start inventing new procedures, unless of course there are no established ones in the first place (i.e. Sioux city).

Btw. When (and where) will we see you article published?

[ 29 August 2001: Message edited by: cosmo kramer ]

[Jackonicko]

Kramer

Stubborn or something else. What something else? Dunno. You had me lost for words.

Sceptical about some of the crew actions? No, critical of some decisions/actions - taking off overweight, not re-calculating limits to take account of the chnaged conditions and shutting down the wrong engine at the wrong time.

But not expecting, or ever advocating that they should have tried to think creatively outside the box. Procedures and checklists are there to help, and should be adhered to. It's standard procedure to stuff the nose down to maintain speed, landing if that's the end result. It goes against every grain of sense to let the speed bleed away in an attempt to reach a particular landing site. Is there a QFI out there who's ever taught anything different. This should not be controversial on a pilot's forum, let alone a professional pilot's forum. A forced landing may kill you. Spinning in definitely will.

You quoted glueb: "overcome the limitations of simulator training and its "mind set" of always being able to return a crippled jet to an airport." NOT MY WORDS, NOT SOMETHING I'VE AGREED WITH.

As to the article. 5K words in a UK aviation mag, possibly 1K in a major Daily newspaper, and almost certainly a radio news feature. Timings/dates still to be decided.

BUT please can we get back to the other questions and away from this sterile force landing/crash landing one. PLEASE!

[Whipping Boy's SATCO]

:confused: Can I put an uninformed (and certainly non-expert) opinion on this post? How about we look at the postulated factors and say that they all, to a greater or lesser degree, contributed towards the crash? Surely we can then say that, with a degree of certainty, various individuals may have been in the position to stop this tragic accident. It seems to me that the incident may have been a classic 'chain of events' that could have been broken: fuel upload, incorrectly configured landing gear, FOD, tailwind on departure, shut down of a serviceable(ish) engine, decision to go for an airfield rather than crash landing, VIP aircraft obstructing the taxyway near the overrun, company pressure to ensure that the Premiere Service is provided on-time on-spec etc etc........

My other point is that we should not seek to muddy the waters. Many of you will be aware of the RAF Chinook crash on the Mull of Kintyre. Although the issue has not yet been put to bed, it has not been helped by idle speculation and "experts" going-off at a tangent.

Off my soapbox and abuse me if necessary. Please just remeber this is a forum for opinion.

[Wino]

Jackinoto,

Show me one transport category jet that had fuel on it and made a successful off airport landing where everyone walked away. Just one. The jets have been flying for almost 50 years.

Furthermore You do NOT stuff the nose down. It is not done in stalls either BTW in a transport category jet. When you do stalls in a jet you maintain pitch attitude and increase power or VERY slightly reduce pitch.

Under no circumstances do you "Stuff the nose" in a transport category jet. They are far more pitch sensitive than a cessna. Concorde is also an extremely pitch sensitive aircraft.

Its normal touchdown angle is HUGE, you cannot be going slow and have any less of an angle, so the aircraft will not pancake in like you think it will. It will strike the tail quite firmly then break up. Mix in 200000 lbs of fuel and everyone will die. Pure and simple. Its a done deal if you try it. If however you get closer to an aerodrome, your odds go up.

Should the Transatt crew just have ditched in the sea? An off airport landing WILL result in deaths. Everything else is just hollywood.

Cheers
Wino
PS. Jackinoto, I was a captain of A320s 737s and 727 for 6 years. I recently changed jobs and went to a larger airline (AA) and am now an A300-605R first officer. Its a wide body, and do not assume that I am less experienced than your other thread members. Among other things, I have been the ALPA safety rep for my airline, part of the "Go team" and a member professional standards. On the management side I have done the engine out ferry and post maintance test flight duties for 2 seperate airlines.

[ 29 August 2001: Message edited by: Wino ]

[Jackonicko]

I wasn't going to rise to this.

OK, so casualties (even fatalities) are very likely in an off airfield landing (Nimrod in the Moray Forth, BTW - a ditching in a Comet where no-one died).

But show me ONE loss of control/departure/spin/ground impact where there were any survivors at all.

And let's not get anal and pedantic about 'stuffing the nose down' - you know what I meant.

[cosmo kramer]

Jackonicko, this is getting stupid and old. Do you really believe that the Captain planned to do a "loss of control/departure/spin/ground impact"? Of course you don't (I hope)! Since crash landing wasn't an option, the Captain took a neck or nothing decision to try to reach Le Bourget. Unfortunately there was probably no cure at that point.

If you mention "why didn't he just land straight ahead?" in your article you will IMO take away some of your credibility.

Btw. as mentioned in the previous thread a delta wing doesn't stall at all (as far as I recall even the late Captain Trubshaw mentioned that in the media after the crash).

[Edit] You didn't specific mention stall anywhere. But a lot of others do. Just before you will be all over me :D

[ 29 August 2001: Message edited by: cosmo kramer ]

[GlueBall]

Wino:
Yes, passengers and crew have walked away from off airport landings in transport category jets! You saw the earlier photo of the Varig 707 crash landed outside Paris where the crew survived and lived to fly another day. (My message on previous page).

In the following photo you see the 737-300 put down in a farmer's field outside New Orleans after dual flameout. Everyone survived. With only superficial damage to the landing gears, the airplane was subsequently stripped of cabin seats and galleys, defueled to minimums and flown off by Boeing test pilots.

I'm sure that somewhere in your AA flight manual you've come across a little known paragraph that says something to the effect: That these emergency or abnormal procedures do not cover all cases or events, but are designed to provide guidance for most inflight emergencies and abnormalities. These published procedures are not intended to limit the crew's good judgement and common sense....

In other words, sometimes you've got to think "outside the box" and do what's unpublished in order to stay alive.


click it (http://www.airdisaster.com/photos/taca-msy/photo.shtml)

:cool:

[BEagle]

I suspect that, once the speed fell below the 3-engine zero rate of climb speed, Capt Marty did not have many options. The 'forced landing' issue is simply not relevant. The large drag rise as IAS decays in a delta soon reaches a point where a vast increase in thrust is required to avoid further deceleration - and even more to accelerate and climb. All he could do was to try and make Le Bourget, but for whatever reason he was unable to maintain control and the aircraft departed controlled flight. Perhaps the IAS fell below Vmca2 as the No 1 engine failed? Who can be certain? But we can certainly be sure that he was trying his best.......

[ 29 August 2001: Message edited by: BEagle ]

[Jolly Tall]

Wino,

Not forgetting the Scandi MD-80 landing in a field in Stockholm after bilateral engine failure. Although some injuries, so I'm not sure everyone 'walked away' by the strictest of definitions, all survived AFAIK.

[Jackonicko]

Cosmo,

I'm not suggesting he spun in deliberately. But how many times did the FO draw his attention to the airspeed? And your contention that crash landing wasn't an option is facile - if he couldn't maintain height, he had to maintain airspeed and crash landing was the only option - though it may have been not much of a choice.


Wino

Noted your new PS. No disrespect intended. Was merely demonstrating that two pros (both ATPLs, one a current FO on twin-jets, one a Captain on something else) couldn't agree. I don't think anyone believes in the old OP Jones image of Captain's infallability any more, describing you as I did was meant to underline the fact that you're a pro with an ATPL, (and jet qualled) not some amatuer PPL monkey or 'untermenschen CPL'. (That, by the way, is a joke. Many P and CPL holders have colossal knowledge and experience. I have personally taken the controls at more than Mach 1 (LIghtning, year dot.) and naturally that makes me an expert on all things supersonic........

Or not!

(Plaintively).
Can we now get back to what went wrong before the aircraft crossed the main road, and finally cease wittering on and on and on and on about force-landings, etc.?

The weight issue, the fullness of the tanks, the undercarriage spacer, the poor decision to shut down an engine etc. are more important issues, and we haven't yet come to any conclusions.

[ 29 August 2001: Message edited by: Jackonicko ]

[Hung start]

Here´s a picture of the SAS MD81. Both engines destroyed climbing out of 2-3000 feet, on dec. 27 1991.
120 some pax! 1 serious injury (broken back), some minor injuries, the rest walked off.
Off airport, with no rescue equipment. 6-10 tonnes of fuel (dunno exact, but that would be a normal amount for STO-CPH trip)
But see, they landed on a snow covered field, that may have saved them from turning into a big fireball! http://www.airdisaster.com/photos/sas751/4.shtml

[ 30 August 2001: Message edited by: Hung start ]

[GlueBall]

Jacko:
As to the alleged overweight condition I wouldn't attribute that to a causal factor of the crash nor of being responsible for a tire failure. An airplane with a MTOW of 185,000 kg to be overweight by 2% is relatively insignificant. Besides, in the case of this crash, at the time of rotation enough fuel was already burned off and spilled out of the wing to put the airplane below MTOW. So, in fact at liftoff the airplane was not overweight.
As to the potential tire overload during taxi, that's not significant either because tire loads during taxi are much less stressful than at 180+ kts during heavy weight takeoffs. Imagine also the potential tire overloads during a rough touchdown. Keep in mind also that the boggie gear is designed to carry the overload of one blown tire. Proper inflation is more critical than momentary overloads. In fact maintenance procedure of replacing a blown tire includes the simultaneous replacement of the "good" tire on the opposite axle, because that tire had absorbed the overload of the blown tire.
Obviously there is lots of redundancy in tire strength.
The absence of a BA modified deflector shield is altogether more significant as it could have helped in deflecting some pieces of rubber from the wing and from the engine intakes.
During any MTOW on any airplane it's unknowable whether or not the airplane is actually above MTOW. Because individual passengers and carry on luggage is not weighed. Formulas are used for winter when passengers carry heavier clothing, and formulas are used for summer when passengers carry lighter clothes. And formulas are an approved method.

:cool:
edited for error: deflector vs. spacer. Thanks Spag.
[ 30 August 2001: Message edited by: GlueBall ] Typo.

[ 30 August 2001: Message edited by: GlueBall ]

[spagiola]

The absence of the spacer is altogether more significant as it could have helped in deflecting some pieces of rubber from the wing and from the engine intakes.

Is there a confusion here? The Air France Concorde that crashed was missing a spacer on the landing gear that keeps the wheels aligned and properly separated. That was because it was inadvertently not replaced after maintenance some time earlier. As I understand it, all Air France Concordes also lack a protective shield that BA has installed on the undercarriage of its Concordes, to help deflect any debris from blown tyres away from the wing.

You talk about the 'missing spacer', but it sounds like you mean the 'missing shield'. There is no way the missing spacer could have deflected debris, had it been present. The worries about the missing spacer is that it might have slowed the aircraft's acceleration and induced a yaw because of the misaligned wheels.

Let's make sure we don't get ourselves any more confused than we already are.

[GlueBall]

Spag:
Correct. Deflector shield, not spacer.

[llamas]

Reagrding Glueball's comments about margins and redundancies in compoenents and the likelihood of their being a contributing factor to the wreck -

I've read this kind of thinking in many places and as an engineer, it bothers the heck out of me. I hope that this is not common thinking among aircrew.

Sure, engineers design margin into most things, and in the airplane business, those margins are very well-defined and specifically tested. So far, so good.

But the limit - eg the MTOW printed in the owner' manual - is not a black-and-white thing. IOW, just becauseyou are at or below that limit, does not mean that the performance of (insert part name here) will be as every bit asgood as it will for every lower loading condition. As you approach that limit, the margin designed into the part is consumed in direct proportion.

If you are at the limit - or, as it appears in this case, if you exceed the limit - you start eating margin even more rapidly, because now the part that you have stressed above its intended limit may now be asked to accomodate another failure in another area.

Bear in mind also that the analysis and testing used to set that design limit and margin of safety is only as good as the limits under which it was performed. For example, as in this case - the MTOW is intimately connected with the capacity and the margins of the tires. But did those calculations include the possibility that the wheel specer mentioned - which I understand keeps the tires from touching - was omitted? If they did not, and I doubt that they did - now you have an unknown eating away at your margin, which you have already, knowingly, largely consumed.

A single excursion to the margins is usually tolerable. It's the multiple drains upon the margins of a design which lead to catastrophic failure. Some of them may be unknown and unknowable. And it's often the "stepping" of limits which ends users up in the soup - the thinking that says 'we've operated this way before, that means we can again, and again, and again, and we will still have the same margin at this level of operation as we had at lower levels."

For a perfect case study of how this sort of thinking leads to bad outcomes, may I suggest "The Challenger Launch Decision" by (?) Vaughan. A classic example of working at and beyond the margins, and what may result from.

llater,

llamas

[Bof]

Pse don't take offence, but for a moment I thought that the AAIB had been closed down by the powers that be, and had been replaced by a group of pprune accident experts.

[GlueBall]

JacKo:
As to the missing spacer resulting in a potential drift to the left side: Doubtful significance. It is not altogether uncommon for a heavy jet, for example, to have a dragging brake, an anomaly easily overcome through initial nosewheel steering and aerodynamic rudder steering. It's more probable that the jet had drifted to the left because of degraded No.2 engine/afterburner output from early FOD ingestion (asymetric power), and before full aerodynamic rudder authority became available, or perhaps because Marty was late in applying sufficient opposite rudder.

The fact is that the jet got airborne, got to 200 feet and stayed airborne for more than one minute with sufficient control authority to give the crew a choice of a controlled crash or a stall/uncontrolled crash. Everything else is ancillary. The declared takeoff weight, the metal strip, the tire disintegration, the fuel tank puncture, the engine failure, the spacer, the tire pressures, the missing deflector, the fire....all stuff over which the cockpit crew has no direct control over.

From a pilot standpoint I'm given to fly an airplane that is supposedly airworthy, proberly maintained and properly loaded by competent ground staff. I don't know whether the tires are at 200 psi or 175 psi, and I don't know whether we have 10 tons of belly freight or 12 tons or whether or not the freight was weighed properly or correctly converted from kgs to lbs.... But I do know that people make mistakes and that not all data that is presented to me on paper is therefore necessarily correct.
Upon takeoff I may have to deal with a C.G. that's different from what was advertised on the Weight & Balance and different from the takeoff stabilizer setting. I may have an engine failure, I may have smoke from an air conditioning pack. But once airborne I have to adapt and deal with it. I have no choice but to work with what I've got.

And just as the Concorde crew faced an unimaginable inflight terror, there should never be a moment for any pilot to give up the struggle to maintain control of his machine. Level wings with sufficient airspeed is the ultimate ingredient for maintaining control.
:cool:

[GlueBall]

Senior Llamas:
I admire mechanical and structural engineers. To be sure, I am thankful for the built in margins without which we'd all be deader than dead. :cool:

[BEagle]

Glueball - it is the culture which perhaps leads to departures outside Perf A limits which is being questioned, not Capt Marty per se.

Limits are limits. Whilst there may well be a margin of fat in RTOW/ATOW, you simply do NOT know how much. If I ever had a pilot examinee of mine paying lip service to RTOW, he would be grounded immediately. No quarter given! Commercial pressures notwithstanding, any compromise of mandatory safety margins is illegal and must never be permitted.

[spagiola]

Yes, the Concorde got airborne, and rose to some 200 feet. But I find it hard to dismiss the overweight problem and the missing spacer.

The higher the weight, the longer the takeoff run. Similarly, the missing spacer may well have slowed the acceleration of the aircraft, if not before the puncture, definitely after it.

Keep everything else the same and give Marty some extra speed when he pulled the Concorde off the ground (to avoid hitting the 747), and he would have had more options. Maybe he might even have made that tantalizingly close Bourget runway.

That ignoring the change in wind direction had no effect on the crash is illogical on the face of it. Had the Concorde switched runway, how likely is it that it would still have hit the metal FOD and burst a tyre?

I can accept that, as the BEA concluded, the tyre failure and subsequent fuel leak and fire were likely the primary causes of the crash. Not listing many of the other items pointed out in this thread and previous ones as at least contributory causes seems wrong, to me. And dangerous, in that it means little is likely to be done to address these problems.

[Flying Lawyer]

Hasn't Bof made a valid point?
On the one hand, we rightly criticise the 'rentaquote' types whom the media wheel out to give their 'expert' views (ie speculation) after an accident and, on the other, respond to a journalist's questions on this open forum.
To his credit, Jackonicko makes no secret of the fact that he wants the information for professional use. We know that journalists thrive on sensationalism yet, despite Jacko's own comments which suggest he wishes to 'expose' an alleged cover-up, many people seem to all too ready to assist.
Let's not forget that the media/Press is fickle. When BA decided to continue Concorde flights following the accident, it was 'Well done, BA.' for a few days. But, as soon as Concorde was grounded, the tone changed completely and the Press revelled in scare-mongering stories about Concorde being a death-trap which should be grounded!
Personally, I can't wait to see Concorde fly again - and would happily have flown on it without any of the mods which have now been made.
Good news doesn't sell newspapers or make good TV documentaries. Idle speculation is so often reported in the media as 'a source in the industry'.
I'm only an outsider, but why anyone would want to help the Press with 'leads' when experience shows that the end-product is bound to be unfavourable to the industry is beyond my comprehension. :rolleyes:

[Covenant]

I've been watching PPRuNe for a couple of years and contributing occasionally for a little less, and in that time, I've seen most of the threads that pertain to aircraft accidents of various kinds. One attitude that continues to resurface is the: "stop making uniformed guesses and leave it to the experts".

Now, I appreciate that we may not all be expert accident investigators, and we may not have all the facts at our disposal but consider this. If I was leading an accident investigation board, and I wanted to make damn sure that my team left no stone unturned and no possibility unexplored, I could do a lot worse than assemble and eclectic group such as this for a brainstorming session.

The people who contribute to this BBS come from backgrounds which include pilots, cabin crew, flight engineers, ground crew, ATC, aircraft technicians, design engineers, accident investigators and yes, even the bean counters! :)

What I'm saying is that although we aren't the acknowledged experts in charge of the official investigation, it does no harm for it to be discussed, and I certainly don't think it's necessary to have a gag placed on us so we have to wait like sheep for the official investigation results.

For example, a lot of people have serious reservations about the official version of the Egyptair crash, and we know that politics can often distort or conceal the truth. I think it is sensible, and quite acceptable for a BBS such as this to be discussing aspects of the investigation and asking questions of the official investigation conclusions.

On a different note, I echo one of the earlier contributor's concerns with regard to besmirching the name of a deceased pilot. It is true that no one wants to speak ill of the dead, and I sincerely hope that no relatives or close friends of the flight crew are exposed to all this supposition and theorising, but it is certainly not acceptable to whitewash over the failings (if there were any) of anyone who may or may not have contributed to such a tragedy simply, because they themselves are dead. After all, who speaks up for the other hundred or so people who lost their lives and who placed themselves in the hands of the flight crew?

A fine man he may have been. A great pilot he may have been. But even the best of us make mistakes, especially in difficult and stressful situations such as this must have been. If (and I stress the word "if") he made any mistakes which could be considered to be contributory, then everyone has a right to know it, not least to help prevent future similar tragedies.

Death makes you neither infallible nor heroic, although it may be tempting and entirely natural to believe so.

[Bof]

I bow to your arguments Covenant. Thanks for an excellent post. A well balanced well written opinion.

[ATC Watcher]

Very, very well said Covenant !
This afternoon, Passing through CDG, there was one of the AFR Concorde parked, dozens of guys working around it in the rain...I am told that lots of maintenance staff comes on their off days to make sure it will fly again.
I Hope they succeed..

[virgin]

Good, thought-provoking posts by both FL and Covenant.
If this was a closed forum, confined to the industry, I might agree with Covenant. But it's not. What is Covenant suggesting? What is to be achieved by this informal investigating body? Do we expect the official investigators to read Prune and take views into account?
I'm totally with FL for the reasons he gives.
BA are about to have Concorde flying again. I for one am pleased about it even if they are the competition. Let's just celebrate.
Anyone who thinks the media will give a balanced account in whatever they write/broadcast is IMHO extremely naive. What documentary into the industry has ever been balanced? The media looks to sensationalise everything for 'shock horror exposure' melodramatic effect.
Most people/companies/industries who co-operate with the media in the naive belief that the final programme/feature will be balanced live to regret it.
IF the accident was due to pilot misjudgement/error then, in the interests of the reputation/future of Concorde, I hope that is made clear. But, whatever shortcomings the official investigation team have, I wouldn't trust the media/Press to investigate - they have no interest in searching for the truth, all they care about is a good story.

[ 30 August 2001: Message edited by: virgin ]

[beaver eager]

I withdrew from the previous thread some time ago after reading several postings in the BA private forum. BOAC (the Head Honcho BA forum moderator) had posted a link to the previous thread in the BA private forum, entitled “Calling all Concorders”. In it he copied Jackonicko’s plea for information from Concorde pilots… Anyone with the required privileges to re-post this request in the BA section? There were very few replies but one correspondent posted the following… I haven't replied to that thread because it's just too big and developing into the usual battle of personalities rather than exchange of info.

I felt that I had been partly sucked into that battle of personalities (despite trying to remain objective) and have since remained (until now) as a spectator on the sidelines. I would now like to add to my previous contributions as I feel that there is a previously undiscussed possibility worthy of an airing. I should like to state though, for the avoidance of doubt (although some may find it blindingly obvious), that I have never been anywhere near a Concorde and have no knowledge of anything “Concorde specific”.

In the previous thread, I supported the theory that a contributing factor to the eventual loss of control may have been that the First Officer, when bringing Marty’s attention to “The Airspeed Indicator… The Airspeed Indicator” failed to add the command “Pitch Down”. I cited possible sensory overload as a reason for Marty’s failure to take corrective action against the obviously decreasing airspeed.

I would now like to suggest an alternative (and in many ways less un-attractive) scenario.

I have learned from these threads that Concorde cannot apparently stall in the conventional sense. Surely though, it must have a limiting angle of attack and therefore some protection against exceeding it? Yet there appear to be no sounds printed in the CVR transcript which relate to any “Stall Warner” or “Stick Shaker”. This may be related to why the First Officer gave no “Pitch Down” commands with his “Airspeed Indicator” warnings.

Perhaps on each prompt of “Airspeed Indicator” (excellent input from the NHP in a sensory overload scenario) Marty snapped out of whatever fifteen other things were occupying his selective attention at that moment (let’s face it, there was an awful lot going on at the time!) and DID actually pitch the nose down to retain flying speed. There would then have been no need for the NHP to issue the command “pitch down” and no automated warnings either.

I offer you the thought that perhaps Marty did NOT at any time allow the airspeed to reduce below flying speed and that the loss of control may well have been caused by the raging fire (I think we can all agree that it was raging, can’t we?) burning through control surfaces or actuating mechanisms.

Without knowledge from the Flight Data Recorder of the pitch angles at the moments immediately before and after the “Airspeed Indicator” warnings by the First Officer, this remains as speculative as any other theory. It is, however, a theory that is much kinder to the memory of the crew , and at least offers a way out of the arguments about whether an off-field landing should have been attempted.

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

Wrt the validity (or otherwise) of debating this here on PPRuNe... Perhaps some take BBs such as this too seriously. Whilst the internet can be a useful tool for the exchange of information, my primary purpose in posting on any forum is to amuse myself. That amusement takes a more or less serious tone depending on the topic (and I have been taking this one rather seriously), but in a worldwide circus such as the internet you do have to remember that it is all things to all people. That is its very strength.

Back to the sidelines...

[Hoverman]

Beaver Eager says
" ..... in a worldwide circus such as the internet you do have to remember that it is all things to all people. That is its very strength."
I agree, but it is also its weakness for the reason F/L gave.
'All things to all people' includes the Press reading what we say. Remember the quotes in the Press taken from Prune re the C4/BA pilots documentary?
Wise words F/L.

[Al Weaver]

"If this was a closed forum, confined to the industry, I might agree with Covenant. But it's not. What is Covenant suggesting? What is to be achieved by this informal investigating body? Do we expect the official investigators to read Prune and take views into account?"

The views on this forum are actually helpful. Many investigators are experts in their own specialized fields and generalists in the rest, yet they are official representatives of larger parties to an investigation. Taken as a single expert, they certainly aren't keys to the final answer yet taken as collective viewpoints they are often solicited for areas of further investigation in scope and technical depth. Some of you complain about suspicions of protecting the "party line" especially for manufacturer representatives. Given that most investigation teams consist of multiple parties and their experts, some of us do pay attention to the viewpoints expressed by others, including these forums and do ask questions and express opinions affecting the investigation based on all sources of information that we can achieve.

I have stated in other forums that at least some of the suggested briefing material released after decoding a CVR does take into account issues raised in public domains that can be placed in perspective by what we hear on the CVR.

Keep up the informed questioning, somebody is listening.

[Jackonicko]

I'm always quite shocked at the hatred and contempt which inevitably arises when the media and journos are discussed - especially on PPRuNe. We seem to be the new lawyers or accountants, or even traffic wardens. I can understand the reaction, to a certain extent.

I can see that aviation is seldom well served by the media, which does have too strong a 'generalist tradition' which does not help in accurate, insightful reporting of what may be complex, technical issues.

There are few specialised aviation correspondents in the general news media, and some highly respected specialised aviation magazines sometimes seem to be little more than rehashed company press releases, often with little analysis or expert comment, and sometimes flawed with errors.

But for the benefeit of Flying Lawyer, Hoverman and Virgin can I offer some reassurance. Were I merely looking for a set of 'rentaquotes' I could have gone and written my piece days ago. I want a broad and representative mix of 'expert' views (including informed speculation, there's nothing wrong with that) and I don't expect to come up with anything terribly sensationalist. I may well not even reach a conclusion, but only report an unresolved debate about factors which may have contributed to an accident. My piece will be balanced, and will reflect the fact that not everyone agrees with what I might believe. I would challenge anyone to point to any article in which I have 'unhelpfully' quoted (or even unhelpfully plagiarised) from PPRuNe or even to accuse me of being other than aviation friendly, and sympathetic to the broad needs and aims of the aerospace community. There are some media good guys, and I hope that I'm one of them!

I'm not especially looking to 'expose' any alleged cover-up, I'm just looking for some answers that aren't given in the official report - and let's not forget that there is some scepticism even among aircrew that this will tell the whole unvarnished truth. I want to fill in the gaps, let my readers know more about this fascinating debate, and reflect that there may be some vague unease in certain quarters, and no more than that.

You may believe that the vast bulk of the media/Press is fickle, because some journos have annoyed you, but to generalise like this would be as silly as it would for me to generalise about all pilots based on the actions of those few who may have annoyed me. I'm still saying 'Well done, BA.' and I've never yet 'revelled in scare-mongering stories about Concorde being a death-trap', nor did I ever call for its immediate grounding - quite the reverse.

Why should people help the Press? Well to help ensure that journos have no excuse for not getting their facts right, and to ensure that there is the best possible chance of the media 'getting it right', for starters, and to encourage greater air mindedness in the general population. Your belief that the end-product is bound to be unfavourable to the industry is, in my view, unduly pessimistic, and I hope to prove you wrong.

In this specific case, there seems to be a real worry that some pertinent factors may have been overlooked, and that these should be highlighted, if only so that they can serve as potential flight safety lessons.

Covenant made the point that brainstorming by an 'eclectic group such as this' could be of value in ensuring that no stone is left unturned and no possibility left unexplored, and I can only add that this might be even more useful if there is even the slightest suspicion of the accident report having been produced with political or other considerations in mind. If the widest possible audience are aware of this professional disquiet, and if there is a media spotlight, then it makes it more difficult for anyone involved to get away with anything vaguely shabby.

Please give this journo, at least, the benefeit of the doubt.

[BEagle]

At least most people hold journos higher in the pecking order than wheel-clampers or airport security jobsworths!!

Regrettably there are some well known journos who just trot out something they've picked up and publish anything for a story, even if it's glaringly wrong and riddled with inaccuracies: 'Giant Jet in horror death plunge, millions put at risk' when ATC merely requested an expeditious descent and that sort of thing!

If cousin Nigel has been reading this thread and has access to Concorde planning data, could he please confirm the RTOW for the accident aircraft using the actual W/V (090/08), OAT and QNH passed to the crew?

[Evo7]

Jackonicko

The media quite rightly has a "strong generalist tradition", and nobody would mind this if the reporting was fundamentally correct. The problem is that so much of it is just wrong, written by people who seemingly do not care at all about the accuracy of what they are writing. On PPRuNe the complaints are about the poor quality of aviation reporting, but it's a pattern repeated across the board.

I'm not saying that you are one of these journalists, and the very fact that you are here now would suggest that you aren't. You're just suffering for the actions of others in your profession. Does it surprise me? Sorry, but no.

[Capt H Peacock]

BEagleCan I just re-iterate what I posted earlier. The weather from the ATIS was as follows (wind) 15k, NIL, FEW018,FEW023,BKN033,19/--, H1008. The wind had been left out of the report until the erratum of the interim report when it emerged as 080/08kts. The aircraft was known to be overweight to the crew, because this is what was on the recorder (my translation – c’est bonne, je t’assure)

14:13:13 - Engineer “on the gauges I have 96.4 with 96.3 for 95 on board”

14:14:04 – First Officer “ZFW and ZFW CG”, Engineer- “I have 91.9 and 52.2”

That gives a weight leaving the ramp of 91.9 + 96.3 = 188.2 tonnes. Just before take-off the Captain asks this question:

14:40:19 Captain – “How much have we used?” Engineer – “There you had 800 kilos”

14:42:31 Captain – “Go”

They had used just 800kgs 2mins 12 sec before the start of the take-off roll so if we allow say 200 kgs for the last two minutes, that means that using the same information that the crew used, the weight was 188.2-0.8-0.2=187.2 tonnes

That is at least 2 tonnes over the structural limit of 185075 and according to a brief analysis with a friend of mine, who would know these things, they were 6 or 7 tonnes over for the tailwind case. That is not speculation or surmise, that is a direct transcript from the CVR and is the data that the crew were assuming for their performance.

JackonickoPerhaps you will excuse the regard in which pilots hold journalists. We seem to have had a rather hapless experience in the past, and unfortunately it seems the public form their perceptions from what they see and read. We wince every time we read Disaster jet in near smash horror at 30000ft. Thousands almost killed. My night of passion with red hot sexy skipper – busty Belinda tells all.

Please remember that we as pilots bear considerable responsibility with little power, whilst you guys have considerable power, often exercised with little responsibility.

[llamas]

lomapaseo wrote:

"The views on this forum are actually helpful. Many investigators are experts in their own specialized fields and generalists in the rest, yet they are official representatives of larger parties to an investigation. Taken as a single expert, they certainly aren't keys to the final answer yet taken as collective viewpoints they are often solicited for areas of further investigation in scope and technical depth. Some of you complain about suspicions of protecting the "party line" especially for manufacturer representatives. Given that most investigation teams consist of multiple parties and their experts, some of us do pay attention to the viewpoints expressed by others, including these forums and do ask questions and express opinions affecting the investigation based on all sources of information that we can achieve."

To lift from a previous recommendation - we might want to remember, for example, that the root cause of the failure which led to the Challenger explosion was first identified, investigated and then put to the public and the press in a form which all could understand by Professor Richard P. Feynmann, a Nobel laureate in physics but a man who, by his own admission, knew absolutely nothing specific about spacecraft or accident investigation. Who, having once seen it, could forget his tabletop demonstration with a C-clamp and a glass of icewater?

Of course experts in all fields of interest are vital to a full and complete understanding of what went wrong here. But I humbly submit that accident investigations would benefit from the presence of a few generalists - folks who are not members of a specific system community, but who have the skills to look at the bigger picture. Reports from a committee of dedicated experts tend to have the same value as designs by a committee of dedicated experts.

JMHO.

llater,

llamas

[Vfrpilotpb]

If you take a look at the Daily Mail of today, the article that is written by Ephriam
Hardcastle echos wording that can be found on this thread , all about the problems with the Concorde before take off, so we must assume(always a dangerous pastime) that these sort's are looking at everything to write about,that could be sensational.

Jackino, you might be the nicest,sweetest man since the last Lord Lucan, but your trade puts you somewhat outside the area of normal thinking peoples trust, sorry old boy! :eek:

[John Farley]

Getting at the truth after an aircraft accident used to be easier in the past than it is today.

Probably the first AAIB investigation that was obviously affected by ongoing litigation aspects was the Staines Papa India Trident accident.

For what it is worth, I believe there are some very honest investigators in the AAIB, NTSB and the BEA. However, such is the complexity of modern types and the operational situations in which they crash, these full time honest men cannot do a meaningful investigation without the help of outside experts. The specialist knowledge they lack is often only available from the manufacturers and the operators of the aircraft that has crashed. This process, whereby such specialists take part in any investigation is known as the “party process.”

In the USA the integrity of the party process, as it affects the NTSB, was recently reported on by RAND. I quote from their report entitled Safety in the Skies:

The party process presents inherent conflicts of interest for entities that are both parties in an investigation and “parties defendant” in related litigation. Indeed, RAND has found that, at least in certain complex types of accidents, the party system is potentially unreliable and that party representatives may be acting to further various interests beyond prevention of a similar accident. Such potential conflicts may, in some instances, threaten the integrity of the NTSB investigative process, raising numerous questions about the extent to which party representatives are motivated to influence the outcome of the safety-related investigation in anticipation of litigation. NTSB

There is much more in the report than it is reasonable to quote here, but it all essentially says some people may lie because their boss tells them to. Sadly, I don’t find that surprising.

If the media are helped to understand the issues they might aid getting at the truth - or at least make it harder to bury it. Its possible Jacko could make a difference here.

[Al Weaver]

I don't have very much faith in the Rand report since it was produced under the self serving authorization of the NTSB itself. It makes an excellent case for increasing the size and budget of the NTSB. On the other side is the party system and its ability to bring product specific experts to the investigation. The balances at work in the party system (against undue influence) are both the other parties and their experts as well as the IIC of the NTSB. As far as I can see the current system works quite well

[Jackonicko]

To doubt the substance of the official report makes one neither xenophobic, nor even anti-Concorde or anti-Air France. Two ex Air France Concorde aircrew (Jean-Marie Chauve and Michael Suaud) have presented their own report to the French judicial enquiry into the crash.

I haven't seen it or found it on the net, yet, but understand it includes the astonishing revelation that the aircraft didn't hit the metal wear strip until after the tyre blow out!

They also point out that had acceleration been normal, the aircraft would have been airborne 50 yards before reaching it.

[fireflybob]

Essentially all we are seeking in this accident (and come to that any other) is the truth and what caused it to happen.

Do we trust the official authorities to publish a report which is factually correct?

I am sure that the professional crew members and also the fare paying passengers who perished in this awful accident would want everyone to know exactly what happened and why. We owe it to these people and their family and friends and also all those who will travel on Concorde in the future to ensure that no stone is left unturned.

[Covenant]

Having read a number of posts to the effect that delta wings do not stall, I was left feeling vaguely uncomfortable. I am not a pilot, but one of my specialisations in my degree course was aircraft aerodynamics, so I decided to go back and have a look at my text books.

I have in front of me a graph plotting lift coefficient against angle of attack for two different wings: high and low aspect ratio (essentially the difference, from a lift perspective, between conventional and delta wings).

http://users.snip.net/~pjspring/images/clvalpha.gif

For the purposes of simplicity, I'm going to assume that a normal airliner wing is pure trapezoidal and that concorde is pure delta. The truth is somewhere in between, but it's close enough to demonstrate my point.

A trapezoidal wing starts to exhibit flow separation at high angles of attack (12-15 degrees) which leads to flow break-down and finally stall, with the lift coefficient markedly dropping off thereafter.

In contrast, the delta wings exhibits flow separation at even low angles of attack, but the vortices thus produced behind the leading edge are stable and actually contribute to the lift, with flow reattachment occuring at some point on the wing before the trailing edge. This stable leading edge vortex formation contunues up until angles of attack near 25 degrees where the lift coefficient starts to drop off again.

This behaviour is simply explained by the fact that, at high angles of attack (greater than 10 degrees), the leading edge vortex turns away as a free vortex in the main flow direction and, although it continues to provide lift, it increasingly creates reverse flow areas and stagnation zones in the wingtip area. This effect can be readily seen in the creation of tip vortices which are often visible when condorde lands at high alpha.

I suppose it depends a lot on your definition of the word "stall" - which is not actually a precise engineering term. If you define it as the point where your lift coefficient against alpha curve turns the corner, then yes, delta wings do stall eventually.

This graph doesn't even tell the whole story though, because it assumes a constant airflow across the wings (constant airspeed).

Another factor in the difference between high and low aspect ratio wings, which is very important in this instance, is that the drag coefficient increases very much quicker in a delta wing with high angles of attack, and even more so with the formation of tip vortices, which are basically just a waste of energy (pretty, but wasteful :) ).

A delta wing aircraft that is low on power, such as concorde was, really cannot afford to go to high angles of attack because of the dramatic effect on airspeed. Even a delta wing, with its better performace at high alpha, will produce less lift if the airspeed drops off. Without a whole load of power at your disposal, increasing angle of attack is an inefficient trade-off to gain a little short-term lift for a lot of airspeed - much more so than with a conventional wing. Sooner or later gravity will inexorably take over and the aircraft will spin out of the sky.

If that's not stalling, then I don't know what is!!

[edited to add a sentence for increased clarity]

[ 01 September 2001: Message edited by: Covenant ]

[edited to add graph]

[ 01 September 2001: Message edited by: Covenant ]

[Covenant]

As a postscript to my previous post (pun not intended), I'd like to follow up on something an earlier contributor said about the normal response of a pilot to loss of lift.

As I have already stated, I'm not a pilot, but as I understand it, the way to get maximum lift out of an airliner with conventional wings is to pull the stick back until you feel the stick shaker, and then hold it just forward of that. This is borne out by the graph I included above - although I still think this action depends very much on you having sufficient available power to overcome the increased drag.

Maybe a concorde pilot, or a military pilot who has flown delta wing jets, can confirm what I believe to be a different approach altogether for delta winged aircraft. I suspect there is a point on the low-aspect ratio wing curve where your trade off of lift versus drag with angle of attack is at its most beneficial. This would vary with available power, as it would with a conventional wing, but whatever the case, I am sure it is well below what we might for the sake of argument call the "stall" point.

My point is that for a delta wing, I suspect there is an optimal angle of attack, probably below 20 degrees, which is not heralded by buffet or stick-shaker and beyond which you should not go without masses of available power to pull you out of trouble.

Again - please understand that there is no disrespect intended - but I wonder if Capt. Marty suffered from his extensive experience with conventional wing aircraft and assumed (granted that we already know he apparently disregarded or failed to comprehend the airspeed warnings from his F/O) that as long as he didn't feel the stick shaker, he could keep pulling back for as long as necessary to reach Le Bourget. In hindsight, with 20-20 vision, time to analyse and reflect, etc, etc, maybe the best course of action from an aerodynamic point of view would have been to allow the nose to come down more and accept the sink rate but at least maintain some airspeed (energy).

I concede that the extreme pitch up that concorde experienced may have been due to a number of factors beyond the pilot's control; for example a rapidly changing COG due to loss of fuel forward of the already unusually aft-situated COG or fire damage to the control surfaces. My comments above are based on the supposition that the increasing pitch up of the nose was due to pilot input.

This is not submitted as factual representation of events on that fateful day, or indeed to imply that this was anything but another minor consideration in the train of unfortunate events, but merely as another point to consider among the many others we have been discussing.

Addendum
Since writing this, I have become convinced that Capt. Marty did the very best he could to extract maximum performance out of concorde in rapidly deteriorating conditions.

I am not deleting this post so that the thread will retain its continuity and the later posts make some sense, however I withdraw any speculation that Capt. Marty could have acted in any other way to prolong the controlled flight of the aircraft at that time.

I have also since been corrected about concorde's design in that a stick shaker (or similar) is included and operates well below the theoretical maximum alpha of the aircraft - not to warn of imminent stall, but to give the pilot intuitive feedback that he is pushing the boundaries of the design envelope.

[edited for typo]

[ 01 September 2001: Message edited by: Covenant ]

[edited for clarity]

[ 01 September 2001: Message edited by: Covenant ]

[edited to include retraction and correction]

[ 04 September 2001: Message edited by: Covenant ]

[N1/TOGA]

you are a very bad journalist jackonicko.

you should read the 3 BEA reports, it's a minimum.

- "tyre retreads" BEA report 1

- threshold wind at 14:43 R26:090/3 R08:320/3
14:44 R26:020/3 R08:300/3

- max performance T/O weight limitation :
186700 kg

- 96.3/96.4 = only fuel gauges indication!(max fuel quantity : 119280l+1630l at0.792kg)
actual fuel 94.8 = 119280l + 300l
capt H pecock....no comment!!!

- CDG FOD inspections : read the last report
(comparaison with others intl airports)

- engine 1 lost power due to fuel/hot gas
ingestion. (probably the same thing for
engine 2 if F/E didn't cut off)

- the fire and high temperature have
probably reduced wing performance and
damaged inner elevon (aircraft control).

- "missing spacer" BEA say no consequence
normal acceleration, no deviation.
I am not enough expert to be disagree
and it is not the good place to find
experts!!!

- "french judicial enquiry"..."I haven't seen it or found it"...in this case stop your
speculations!!! wait and see!!! and read at least the 3 BEA reports.

The french judicial enquiry has to settle
the responsabilities (and not BEA).

stupid and steril topic .

[Jackonicko]

N1 TOGA

Please have the decency to be civil, old chap. "You are a very bad journalist" is hardly a good start, is it? The last Concorde thread did start getting nasty, but we're all trying hard on this one to be more measured.

And when senior Captains of large jet airliners, a test pilot of John Farley's reputation, and other informed aviation people express concerns about this subject, it can hardly be 'stupid and sterile', can it? Your lack of respect for your fellow Pruners does you no credit.

For information, I have read all the BEA documents available in English, and have waded through some of them in French (especially the CVR transcript). We know that the report by the two French Concorde captains (presumably 'not experts' according to you) disagrees with some of its findings.

There are many experts on this thread too, and some of them have expressed a belief that the BEA report (only an interim document at present) may be quite seriously flawed, and have explained why. Some are concerned that there have been a succession of flawed reports from the BEA, while others believe that there is always a tendency for reports (not just French ones) to be shaped by commercial or political interests. Yet you choose to give it the respect normally accorded to holy scriptures.

Because you have very kindly posted in English, there are parts of your post that I don't really understand, and thus don't want to answer.

The first one concerns take off weight, where you seem to be disputing the fact that they took off overweight.

The summary of the case for this argument is as follows:

From the accident report we can see that they took off at 187.2 tonnes.

The max structural weight is 185.075 tonnes (not 186.700).

Even if the aircraft was marginally below its absolute structural limit by the time it reached its take off position (and are we sure it had done?) then the 8kt tailwind was sufficient to reduce the Regulated TO Weight (the weight at which it was legal and safe to take off) to a figure below that of the Actual Take Off Weight - so in summary, they took off overweight.

Can you explain how you disagree with this? (Can those who posted these figures originally quote a source, with report and page no., just for the record?)

You go on to state unequivocally that engine 1 lost power due to fuel/hot gas
ingestion, whereas Rolls Royces tests suggest that this verdict may be shaky, and some experts suggest that solid object damage (perhaps the runway edge light) was what stopped it. Speculating on what 'would' have caused No.2 to fail is specious. The engine had not failed and was producing thrust when it was deliberately shut down, without a direct order to do so from the captain.

You speculate that the fire and high temperature 'have probably reduced wing performance and damaged inner elevon (aircraft control)'. You may be correct, but there is no evidence to support this. Captain Marty lost control because he was too slow and at too high an AoA.

BEA may say that the "missing spacer" was of no consequence, but a number of highly qualified experts disagree, and we have already suggested that there are reasons for some people to suggest or suspect that the BEA's conclusions may not be impartial, and may have been tempered by a desire to protect the reputations of the nationalised airline and Aeroports de Paris.

You admit that you are "not enough expert to be disagree" (your profile does not even tell us whether you have any aviation expertise at all, nor whether you even hold a basic PPL) yet you seemingly fail to recognise that others (who are experts - including an accident investigator) do feel that this kind of discussion on PPRuNe is useful, and valuable, and do respect the expertise of many of those contributing to the debate.

If your start and end point is that you can't believe that there is any possibility that the BEA could have got it wrong (by accident or design) perhaps there is no point in arguing.

[John Farley]

lompaseo

Thank you for that.

Yes NTSB asked Rand to do the investigation. Yes the report does make an excellent case for a bigger NTSB budget, but my word it is also quite scathing in what it says about the management of the NTSB.

It lists good reasons for saying things like:

The NTSB must substantially revise its practices, more closely manage its resources, and break the cultural insularity that is widening the gap between its staff and the broader aviation community. NTSB’s leadership must make the requisite improvements while continuing to ensure the independence of investigations and the leadership of its professional staff.

Not altogether self-serving stuff in my book.

Regards

[John Farley]

Covenant

Nice to see two very informative posts that tidy up some things that others have said – perhaps without full consideration. A couple of points regarding what you said came to mind.

Before I get to those, I must admit that I have never flown Concorde, but I was lucky enough in the mid sixties to fly both the RAE single seat aircraft (HP115 and BAC221) that were purpose designed to study the handling and performance characteristics of the projected Concorde planform. I also flew a Vulcan specially modified to look at piloting aspects of engine failure on take off as it would apply to the Concorde, as well as spent many a long hour in the Bristol Concorde simulator – then used for development and now the primary training aid for today’s crews.

This work, on behalf of the RAE boffins, left me in no doubt that the increase in drag that you refer to (when a delta flies slowly at higher angles of attack than ordinary wings can reach without stalling) is the dominating characteristic of such flight. Indeed it leads to the notion of the zero rate of climb speed (Vzrc) that is mentioned in several appropriate places in the BEA reports. If you slow down to this speed you (by definition) need full throttle just to hold that speed in level flight. One knot (or more) slower and you are in big trouble. You must lower the nose so as to reduce lift and the associated induced drag, which means you give away height in order to pick up speed. Just like the stall recovery case for conventional types. When I left that scene the boffins were seeing this Vzrc as the direct equivalent of Vs for all certification purposes. It is not a stall but it has the same effect as one and margins (1.3 or whatever) would need to be provided to keep pilots away from it just like the stall.

That I guess is neither good nor bad news. But what is very bad news is that the Vzrc is hugely dependent on the amount of thrust at your disposal. If you chop a donk Vzrc may leap up 20 or 30 knots or more depending on the aeroplane concerned. Now you are talking of a much more lethal effect than the slight increase of stalling speed that happens when thrust is lost on most aircraft.

With this in mind the linear part of the “delta wing” curve in your diagram above may not all be usable in level flight – or there again it may be possible to go right over the top and down the backside quite easily if you have monster amounts of thrust attached to your left hand (watch the Russians at airshows). But being on that part of your curve may (again depending on the design) bring about huge trim changes leading to loss of attitude control with even low levels of turbulence.

Perhaps all this is why one hears so much talk about “departures” rather than “stalls” these days. I like it when people talk about the aircraft “departed from controlled flight” because it is all embracing and not just about lift (or the lack of it).

So, months ago, when I first looked at the curves of airspeed, angle of attack and height from the accident flight, I was full of sympathy for Marty’s predicament. For what it is worth, it seems to me that he actually managed to finesse a knot or two at constant height and was initially flying quite brilliantly. Did you notice BTW that when that delicate balance was eventually lost (perhaps due to fire damage of the aerodynamic surfaces with associated change in longitudinal response) how high the aircraft shot up as the lift available at the suddenly increased angle of attack momentarily took charge?

Regards

edited for usb finger trouble

[ 01 September 2001: Message edited by: John Farley ]

[JPJ]

I am awestruck by the quality of this thread. It's what makes PPRuNe a unique aviation resource.

[cosmo kramer]

Covenant

Check this link for information about Low Aspect Ratio Wings at High Angles of Attack (http://adg.stanford.edu/aa241/highlift/sstclmax.html)

There are some graphs that quite clearly explains what happens to delta wings at high AOA.


At high angles of attack, several phenomena usually distinct from the cruise flow appear. Usually part of the wing begins to stall (separation occurs and the lift over that section is reduced).

but,

When the sweep is very large, or aspect ratio low, this approach does not work. Separation tends to occur near the leading edge of the wing, but unlike in the low sweep situation, the separated region is not large and does not reduce the lift.

--

When the vortex burst occurs on the wing (as opposed to downstream of the wing) the lift drops substantially.

but,

For many SST designs, however, the maximum CL may be predicted by assuming that the vortex does not burst at the maximum permissible angle of attack.

All of the above is backed up by a lot of formulas that doesn't make sense, though, to "normal" human beings :)

you wrote:

Without a whole load of power at your disposal, increasing angle of attack is an inefficient trade-off to gain a little short-term lift for a lot of airspeed - much more so than with a conventional wing. Sooner or later gravity will inexorably take over and the aircraft will spin out of the sky.

If that's not stalling, then I don't know what is!!

I think most here would define stall as the state of flight where the critical angle of attack has been exceeded (i.e. the wing stops producing lift). Drag is another matter and an excess of drag is not the same as a stall, although the consequences may be the same eventually.

-------

But is any of this, or how the Captain flew the aircraft relevant? Isn't it more relevant why they ended up in the messy situation that they did?

[ 01 September 2001: Message edited by: cosmo kramer ]

[John Farley]

Cosmo

Could you join me on Tech Log – Votex bursting?

Regards

[brockenspectre]

John Farley

I just want to thank you for a beautifully simple and professional analysis of what Capt Marty had to deal with. I am "just" a private pilot but would have been more if I wasn't so short-sighted. I have loved Concorde since she first flew and anything that will keep this wonderful bird flying safely and help mere mortals (regular non-Concorde/non Delta-wing pilots) understand the issue is very welcome. From what others have said, and I have read, of the career of Capt Marty, I suspect he would be delighted that (a) we appreciate his predicament and (b) we are debating what happened in Paris so that it need never happen again.

I have to say your analysis of the incredibly fine balance he would have had to maintain in extraordinarily stressful circumstances just shows what a great pilot he was - in extremisrelying on his skills, experience and instinct while knowing, probably, that he and his aircraft would not survive the incident.

:)

P.S. any word on when Concorde will make her first flight to/from LHR?

[BEagle]

Although the Vulcan was a 'conventional' delta rather than a 'slender' delta, it too had unusual handling charcteristics at low IAS - or more correctly at high AoA. These included significant adverse yaw and ultimately roll reversal with use of elevon in the rolling plane requiring cautious use of rudder to control yaw/roll and rapid IAS decay in level flight unless a lower pitch attitude was selected and a descent established. We didn't take the ac to anything close to the limits during our OCU on type, but I certainly remember how unnatural the low IAS/level flight regime was.

Even in the cruise the high drag at low IAS could catch the unwary! We didn't have any low speed buffet boundary limits as I recall, so when day over the south of France at FL410 when the nav plotter asked for a large speed reduction to cope with the unusual high level wind and timing requirements to make good a low level entry time, the captain decelerated to around 190 KIAS; when we tried to accelerate again it wouldn't do so even with the 4 Olympi bellowing as loud as they could. He had seemingly discovered Vzrc4 for that particular flight level and thrust available and it was only with the agreement of ATC allowing us to descend 4000 ft that we managed to accelerate out of the flight regime.

[ 03 September 2001: Message edited by: BEagle ]

[John Farley]

Covenant

In the way of these things I have acquired some manufacturer’s data relevant to flying Concorde slowly that covers some of the points you made here in your 1 Sep 13.01 & 14.35 posts.

I’ll put it over on the Tech Log Vortex bursting thread.

Regards

[Covenant]

Having read some of the posts here and in the Tech Log, from John Farley in particular, I think I should withdraw any speculation on the appropriateness of Capt. Marty's actions that I made in my second post of 1st September. It's quite clear to me now that, all other factors being equal, he was making the very best of a very bad job.

I should have just left my first post to stand as it was. That'll teach me to stick to the facts! :)

Cosmo Kramer
Thanks for the link to the low aspect ratio wings at high alpha treatise. I don't think anything in there contradicts what I said in my first post, although the graph does show the non-linear vortex lift continuing for higher alphas than on my graph - probably because it is describing the theoretical total lift and doesn't allow for vortex bursting which, as the author points out, is not easily predicted using theorectical models.

On the tech log, WOK noted that concorde departs at slightly less than 25 degrees alpha in the sims which I suspect is more due to other stability factors than vortex bursting. I also tend to agree with John Farley that, even with all four engines producing max thrust, concorde would not be able to maintain IAS at such high alpha, which effectively puts vortex bursting well outside the normal (or even abnormal) operating envelope of the aircraft.

Nevertheless, at the point of departure from controlled flight, the aircraft, for whatever reason, experienced a dramatic loss of lift, which is essentially what people mean when they talk about stalling. That this was ultimately due to high alpha, high drag, low power or any combination of the three is not really important. One or both of the wings did, in fact, stop producing lift - which is why the aircraft went down and not up!

As you say, although discussion of this point is interesting, it has little to do with what we should be concentrating on with regard to the causes of the accident. My aim was really to clear up any misunderstanding that may have arisen about the nature of slender delta wings and their performance at high alpha. I think between us all, we have managed to do that fairly comprehensively! :)

[cosmo kramer]

Covenant
Nevertheless, at the point of departure from controlled flight, the aircraft, for whatever reason, experienced a dramatic loss of lift, which is essentially what people mean when they talk about stalling. That this was ultimately due to high alpha, high drag, low power or any combination of the three is not really important.

You are right that isn't important as far as the result goes.

But speaking from a strict definition point of view, I would say that a stall is caused by an exceedance of the angle of attack. Is a wing that is not producing lift stalled? If so is a parked aircraft stalled? ;)

Perhaps, not to clutter up the topic, further posts on this issue should be in Vortex bursting (http://www.pprune.org/cgibin/ultimatebb.cgi?ubb=get_topic&f=3&t=002432) or another new thread in Tech log?

[Jackonicko]

I hesitate to point out to Brit PPRuNers that a Concorde TV documentary is due on Thursday night (BBC 2?) at about 2100. Although I've not seen it, and have had nothing to do with it, I fear that it may generate some anti-journo/anti-media feeling.

But don't blame ME.

PS: What an epic thread! Many thanks to JF and covenant for educating me!

[Shaggy Sheep Driver]

BEagle

Very interested in your comments about Vulcan handling at high A of A. When the lovely bird was flying, the airshow routine seemd to comprise a steep climb, sustained 'till very low airspeed, then a 'wingover', to the right and a dive to recover speed. Given the odd handling at high alpha, that must have been 'interesting', especially for the guys in the back with no bang seats.

Cheers

SSD


PS

Just like to add my thanks to John Farley for his superb contribution to this most interesting thread.

[Jackonicko]

Re weights

Based on that day's met data (a twelve kt headwind, a low QNH (1008), the higher than normal temperature and the usable length of the runway), the dispatcher calculated the maximum weight as 177,930 kg. I'm unclear as to whether this took account of the non-availability of thrust reverser 2, which led to a reduction of 2.5% in the maximum weight permitted.

However, flight preparation showed a takeoff weight of 184,800 kg with one hundred passengers (but not all of the baggage) checked in, and the despatcher then started getting anxious suggesting a route with an optional tech/refuel stop or unloading baggage to follow on another flight - it was at this stage that the crew took over flight planning (in order to stretch or bend the rules?).

The max structural weight is 185.075 tonnes.

From Captain P's reading of the report it has been said that they took off at 187.2 tonnes, though in the latest report it is suggested that the accident investigators recalculated the figures, and came to the conclusion that actual TO weight was an estimated 184,802 kg.

So was the aircraft marginally below its absolute structural limit (as suggested by N1 TOGA) by the time it reached its take off position, or two tonnes overweight (cf max structural), or ten tonnes over the max weight originally calculated by the despatcher. And all of those overweight figures are without the 8 kt tailwind.

Ten tonnes. TEN tonnes? Can some-one confirm that I've got that right?

[Covenant]

After re-reading the BEA reports, I have just noticed a rather critical erratum in the preliminary report which was corrected on page 7 of the first interim report (15/12/2000).

Rather significantly to my earlier post, it says that, with reference to the control column position graph, positive values indicate nose down input rather than nose up, which was how it was shown on the key in the preliminary report.

What this means is that contrary to what I had previously believed, the pilot was constantly using nose down input to the control column from about 12 seconds after rotation. This is especially significant at around time 97667, where it appears the AoA begins to climb out of control. I had originally thought that the pilot responded by pulling the stick back through some 4 degrees (which seemed to make little sense, I admit).

It appears to me now that Marty was indeed trying to hold the AoA to around 12-13 degrees for the bulk of the flight against a tendency to go nose-up, rather than trying to hold the nose of the aircraft up to maintain height, as I had originally thought.

What a difference a little "+" sign makes!

[Edited for the usual typos]

[ 04 September 2001: Message edited by: Covenant ]

[BEagle]

Jacko - I'm pretty sure that the flight despatcher's figure allowed for the known thrust reverser unserviceability and it doesn't have a material bearing on the accident.

The "investigators' recalculation" doesn't make clear whether that was a RTOW or ATOW estimate; it was way short of the ATOW figure known to the crew and that figure was known by them to be in excess of the max permitted certificated structural TOW.

Nowhere in the report do I read a clear and accurate assessment of RTOW based upon the known 8kt tailwind, the actual OAT and QNH at the time. WHY NOT?? Informed comment in this thread puts the figure at around 177T...

Elsewhere, John Farley comments upon Vzrc2 both with the landing gear up and with the landing gear down. Also, we learn that any decrease in thrust at low speed will lead to a rapid loss of speed and an increase in Vzrc. So why would anyone ever consider shutting down any engine still producing thrust with the landing gear still down??

[ 04 September 2001: Message edited by: BEagle ]

[Jackonicko]

BEags: If it's 177 tonnes for that day's OAT and QNH, but with a 12 kt headwind, how much lower for an 8 kt tailwind? What ballpark difference would we expect?

Incidentally, for those who doubt it, the Structural weight limit for take off is 185,070 kg and for taxying is 186,880 kg.

The accident report suggests that the aircraft taxied out at 186,757 - 87,251 kg, and took off at 185,757 - 186,251 kg, though these are guesstimates, based on what the two Air France Concorde chaps producing the report for the magistrate regard as unduly optimistic estimates of baggage and pax weights.

Covenant: With regard to the trace of control column inputs, the idea that all the +s represent stick forward seems bizarre - do the traces show that they pushed forward to rotate (it would be a neat trick)?

Also, the AoA was held to a reasonable level (without much stick input at all), so the subject of stick inputs is hardly relevant - 2° either way hardly represents the Captain pushing forward to keep the nose down (nor pulling back to keep it up) terribly hard. Right up until the final turn, where the speed started to decay (from 208 kts down to 181, and later much lower), the AoA went up and the aircraft's rate of climb began to increase markedly, the Captain was flying it with great delicacy, nursing the aircraft into a gentle climb straight ahead. The lack of 'fighting to keep the AoA down' may also be indicated by the fact that the pilots' had wound in significant nose up trim however, and did nothing to select more nose-down trim.

Also, while the co-pilot kept shouting for airspeed, the captain kept it pegged at 199-211 kts (precision flying, under the circumstances), and the aircraft gently but steadily climbed to 182 ft as it crossed the motorway, and to 300 ft as it began the final turn.

Would you guys have done that, or would you have stayed at 100 ft and tried to get closer to the Vzrc speed as you belted for Le Bourget?

gear up:
two engines 262 kts, three engines 193 kts
gear down:
two engines 300 kts, three engines 205 kts

VMCA:
three engines 132 kts
two engines 157 kts

Did they begin turning for Le Bourget too late (forcing them into turning more tightly, with more angle of bank, than was perhaps wise)? Would you have begun turning earlier (even before crossing the motorway, perhaps turning to intercept the Le Bourget extended centreline, rather than flying a mile beyond it?) would the aircraft have departed in a gentler, faster but much lower turn?

I hear what you've all said about Delta wings stalling, but looking at the altitude/airspeed/AoA traces you can see that the aircraft effectively stalled and spun once airspeed decayed/alpha increased beyond a certain critical point.

If I'm being over-simplistic or showing my PPL limitations, please educate me!

[Covenant]

Jackonicko

The original trace in the preliminary report shows control column negative input as the pilot rotated and for the next approximately 12 seconds where it became positive and remained so for the duration of the flight. The key says "+ Nose Up". The first interim report corrects this to "+ Nose Down".

Of course, if I'd been thinking properly, I'd have realised the error since, as you say, it would be a pretty neat trick to rotate with nose down input on the control column! :)

I don't think I was implying that he was "fighting" to keep the nose down, more that there was a moderate amount of nose down input, contrary to what I had originally thought which led me to wonder if he was trying to maintain altitude at the expense of airspeed.

I see more clearly now :rolleyes:, and think he was more likely, as you suggest, to have been doing some delicate speed control by nudging the nose forward under what power he had available.

To comment on your last few paragraphs, I've been trying to visualise the flight path from the CDR traces, and ended up actually modelling the aircraft for the last 30 seconds of the flight, in a 3D program I use, to try and get my head round it.

Having done that, I would venture to suggest that the real critical problem was not attitude or angle of attack, but roll. As you say, neither of the former parameters was all that excessive for most of the flight, and by the time AoA did become excessive, the roll to the left was around or above 90 degrees. At that point, lift production is purely academic. I don't think the roll angle got this bad because the pilot tried to turn too hard or too late.

I suspect it would have had more to do with control surface problems, specifically elevon failure on the left wing. Since the pilot was demanding slight nose-down during the fire, if one of the left elevons became frozen in place, it's not hard to see how that would cause an unstable situation leading to uncontrollable anticlockwise roll. It may even be that it was this extreme angle of bank which caused the #1 engine to ingest greater quantities of the burning fuel (leaking from inboard of the engines) and finally give up the ghost.

Whatever causes and effects or the actual sequence of events, by this time, the plane was uncontrollable with no more options left to the pilot. Furthermore, with this event about to happen, I don't think there was anything more he could have done at any point during the flight.

In many ways, this also makes all the other questions about TOW, CoG, tailwind, missing spacer bar, and anything else that didn't directly contribute to the fuel fire, purely academic. If your control surfaces lock up, you're in big trouble regardless of your height, speed, or anything else for that matter.

In my mind, it's back to the question of how and why the fuel leak and subsequent fire started; all other questions being interesting but not significant.

[ 05 September 2001: Message edited by: Covenant ]

[BEagle]

Jacko - the 177T RTOW figure was, I believe, an unofficial figure based upon the actual 090/08 wind passed to the crew with their take-off clearance - not the pre-flight calculated value using the ATIS conditions at that time.

We introduced 'late change' data for the Vulcan in 1978 specifically to allow for last minute wind/temp/pressure changes influencing the V speeds - and it's something we teach our VC10 students during their simulator training. It is absolutely fundamental on heavy transport category aircraft to recompute RTOW if the weather values are different to the planned values on departure; equally it is never acceptable to ignore RTOW or max permitted take-off weight limits. I would be very, very unhappy at ever flying in an aircraft whose crews seemingly ignore such limits......

[Jackonicko]

Covenant & BEagle,

Many thanks.

But the AoA was kept as 'tight' as the airspeed until the turn (beginning at point 7 on the photo), where roll rate also increased dramatically.

At point 8 (181 Kts, angle of bank going from 38° to 93°, AoA up to 19.5°) it looks as if he'd lost it - and to my uneducated eye, had over-banked and tried to 'hold' the nose up. At that point, the left wing had (sorry) seemingly 'stalled'. Four seconds later the speed was down to 136 kts, and AoA was 25.15°, while the roll angle was beyond 90° (spin or incipient spin?).

1) Why climb to (and indeed through 200 ft) without coming close to VZRC2?

2) How much more airspeed might they have got if they'd flown level, rather than climbing at about 180 ft per minute?

3) Why not turn gently towards Le Bourget much earlier (the direction the aircraft wants to go, and to keep it straight you're using right rudder)?

I believe that the dispatcher's originally calculated maximum weight was the RTOW for that aircraft on that day in those conditions (177,930 kg - very close to our 177 tonnes) and the fact that the actual TOW was so much higher was what made him start kicking up a fuss. Is it interesting or sinister that the accident report does nothing to explain why his RTOW figure was so much lower than the one they came up with as being 'appropriate', or is this the difference we'd expect for the different RWs - the dispatcher planned for 27, they planned for 26?

From the report:

"Based on data on the wind (a twelve kt headwind), the QNH (low, 1008 hPa), the temperature (higher than the norm) and the usable length of the runway, the dispatcher calculated the maximum weight as 177,930 kg. However, flight preparation showed a takeoff weight of 184,800 kg with the one hundred passengers checked in.

At about 09 h 30, the dispatcher informed the duty officer of the weight problem, without however specifying the QFU used for the calculation. The duty officer first thought of using another aircraft, then tried to resolve the technical problem with the reverser and finally thought of loading the baggage onto another flight.

On his side, the dispatcher studied two hypotheses for routes (one direct and one with an optional technical stop) and loading so that the flight could take place in terms of its weight.

A little before 10 h 00, the crew called the dispatcher who informed them of the problem. The crew informed him that they had asked for the replacement of the failed pneumatic motor on reverser 2, asked him to file a direct ATC flight plan and told him that they were going to take over the flight preparation themselves."

[Paterbrat]

Jacko, perhaps prompted by V1TOGA's posting I can only say that as a pilot and having lost both parents through an airliner crash I, and I think many others, applaud your efforts to obtain a clearer understanding into whatever facts can be reasonably ascertained in the sad ending of that Concord flight.
It can only be hoped that the information thus gleaned will be of use to others. In the meantime I follow your findings and the informed discussions with great interest and hope like us all to see Concord airborne again.

[cosmo kramer]

Jackonicko
I hear what you've all said about Delta wings stalling, but looking at the altitude/airspeed/AoA traces you can see that the aircraft effectively stalled and spun once airspeed decayed/alpha increased beyond a certain critical point.


How can you see that? :confused: The reason I keep digging in this stall thing (which by now we should agree that Concorde doesn't) is because it somewhat implies pilot error. You have no facts to support vortex bursting, which as far as I can read from the Vortex bursting (http://www.pprune.org/cgibin/ultimatebb.cgi?ubb=get_topic&f=3&t=002432) thread would require a hypothically high AoA, and the aircraft would probably become unstablile before reaching that AoA. All you know is that for unknow reasons the aircraft rolled over and crashed (speculation as to why may be e.g. fire damage to the control surfaces). This does not necessarily imply that the wings were not producing lift. However, as Covenant mentioned it is academic to discuss lift if it doesn't act in the opposite direction of gravity (i.e when roll is greather than 90 deg).

At point 8 (181 Kts, angle of bank going from 38° to 93°, AoA up to 19.5°) it looks as if he'd lost it - and to my uneducated eye, had over-banked and tried to 'hold' the nose up.

See above, and atleast support speculation with some facts. Otherwise one might just aswell say that aliens shot it down with a laserbeam ;)

At that point, the left wing had (sorry) seemingly 'stalled'.

If talking about a conventional wing (that stalls ;)), the right wing would stall first in a left turn because it has the highest AoA.


3) Why not turn gently towards Le Bourget much earlier (the direction the aircraft wants to go, and to keep it straight you're using right rudder)?

Are you suggesting that they should have let it sideslip towards Le Bourget (keeping the wings level and let the nose drift)? That is not the most aerodynamic efficient way of flying.

After 150+ post on this topic, I for one, feel more and more confident that the accident was indeed caused by the tireburst and subsequent fire. If it was the fire damage that caused the crash, overweight, engine shut down, etc. would not have been factors that directly contributed to the crash.

[Jackonicko]

Cosmo,

Sorry to upset you with my inexact terminology.

JF wrote: "The increase in drag that you refer to (when a delta flies slowly at higher angles of attack than ordinary wings can reach without stalling) is the dominating characteristic of such flight. Indeed it leads to the notion of the zero rate of climb speed (Vzrc)..... If you slow down to this speed you (by definition) need full throttle just to hold that speed in level flight. One knot (or more) slower and you are in big trouble. You must lower the nose so as to reduce lift and the associated induced drag, which means you give away height in order to pick up speed. Just like the stall recovery case for conventional types. When I left that scene the boffins were seeing this Vzrc as the direct equivalent of Vs for all certification purposes. It is not a stall but it has the same effect as one and margins (1.3 or whatever) would need to be provided to keep pilots away from it just like the stall."

This is why I used the word 'effectively' when I described the process as stalling. Perhaps I should have written:
"looking at the altitude/airspeed/AoA traces you can see that the aircraft departed and spun (there is no doubt that it's final manoeuvre was a spin) once airspeed decayed/and induced drag due to excessive alpha increased beyond a certain critical point."

To suggest that the cause of the departure was control damage (even the BEA does not claim that the controls were not functioning at the time of impact) is as speculative as my suggestion that the pilot mishandled the aircraft (so perhaps you too should support speculation with some facts, or shall we both agree that aliens shot it down with a laserbeam?).

(And to be fair, I don't think my 'speculation' was so very far fetched: "At point 8 (181 Kts, angle of bank going from 38° to 93°, AoA up to 19.5°) it looks as if he'd lost it - and to my uneducated eye, had over-banked and tried to 'hold' the nose up." does it?)

With regard to wings stalling in a turn, isn't the out-of-turn wing travelling faster than the inside wing, with faster relative airflow? In an erect left handed turn which wing stalls first?

To clarify, I'm not suggesting that the pilot should have sideslipped all the way to Le Bourget (though in those circumstances, keeping the ball centred might not have been a prime concern). Do we even know that the aircraft wasn't perhaps already sideslipping, with the constant starboard rudder pressure?

May I challenge you on two questions, since you express yourself so confident that you 'know' what happened?

1) How confident are you that the combination of excessive weight and undercarriage problem didn't exacerbate or even cause the tyre blowout, or, if not that, that it didn't cause the ignition of the fuel?

2) How confident are you that shutting down the No.2 had no effect on the outcome?

3) Can you explain how the outcome would have been the same had Marty traded altitude for airspeed, by not climbing above 100 ft, and had he made a faster, gentler earlier turn towards Le Bourget? Or is it OK for you to speculate, but no-one else.

I don't know the answers, I don't have a firm idea of what caused the tragedy, but I do believe that there may have been multiple factors at work. Why do we need to over-simplify it without evidence that it was simple?

[cosmo kramer]

Jackonicko

We do agree that the aircraft was on fire? Then perhaps the fire could cause damage, besides the obvious, no? I did put brackets around that sentence because it's speculation, however possible. It was only to offer a possibility.

What you don't know is, how the pilot flew - that is pure speculation! You only know how the aircraft reacted. I don't think it's constructive to blame the dead, unless there is a good reason.

The outside wing has a higher AoA because of the downwards defeltion of the aileron. Hence it will stall first.

Flying coordinated is a prime concern as it will reduce drag.

I have no idea what happened, but I have confidence in BEA after reading these threads. But who cares what I believe. :)

As to 3), I believe that it is unfair to question action made under extreeme pressure. The Captain made his decision and that's it. Can anything be learned from questioning his actions? Probably not, because no one would probably ever find themselves in the exact same situation. So what's the point?

If you do believe there were multiple factors at work, what are your plans to find out? Because you are probably not going to find the answers at PPRuNe! Why over-complicate things when there are no proffs that is was complicated?

(Edit: the last remark doesn't mean that I believe that there should be any stones left unturned)

[ 05 September 2001: Message edited by: cosmo kramer ]

[Reheat On]

What a thread. Yikes! However - does anyone know if Concorde was spun in its trials, and if so what were its flicking characteristics in unusual spin entry?

The rate of bank at Point 8 mentioned suggests a flick manouver [unintentional]

Am I not right in concluding that if the outer wing lift degenrates first in an turn [eg R wing in L turn], then rapid roll reversal occurs with the aircraft flicking to the oposite side [ie R] in order to spin?

QED the wing did not suffer lift depletion
QED the aircraft ran out of power ie the Vzrc scenario ceased and a self induced exit began with consequent loss of [critical] altitude

Loss of power in a port engine would allow this to happen and the assynmetric thrust might be suffiecient to give increased lift to the starboard wing.

I realise I am in realms of aerdynamics for anoraks here and would appreciate flaming very slowly ! It seems to me the men from Boeing might be very interested in all this for their Sonic Cruiser.

[BEagle]

OK Chaps - back to basics!

It seems that the aircraft took off above both MTOW and RTOW.

It seems that there might have been damage to the undercarriage caused by poor maintenance and possibly exacerbated by the overweight take-off.

It is certain that a tyre failed. Probably due to an external cause, but perhaps the tyre was also weakened by the overweight take-off.

It is certain that both No 1 and No 2 engine suffered loss of thrust, although the No 1 later recovered.

It seems that the No 2 engine was shut down without a clear command at at time when the Commander was desperately trying to fly his aircraft to an emergency landing at Le Bourget.

During the attempt to reach Le Bourget, despite the heroic attempts of the late Capt Marty and his crew, the aircraft departed from controlled flight.

HE DID HIS BEST!!

[enginefailure]

theories, theories, theories ...........

can u imagine how the pax must have felt ?
Looking out of the window, seeing a burning wing (could they see the fire?) and realizing (those, who have flown before) that the plane didn't reach more then 200 feet in a minute or so - scaring ..........

i really don't know who wants to critizise
the capt for his actions in a scenario, which must have been a hell in the cockpit (alerts all around, only a few feet above the ground with a terrible performing aircraft - and some "experts" think, they would have done better ....)

let them rest in peace !

[BEagle]

Capt John Hutchinson, a retired Concorde captain of very high repute, has just been interviewed on BBC TV. He restated the possible contributory causes in a very clear and precise manner, echoing the doubts concerning the incorrect undercarriage repair, the fact that the aircraft did not use all its taxi fuel and was, as a consequence, 1.2 tonnes over its MTOW; he also confirmed that the 090/08 kt wind passed with the take-off clearance meant that the aircraft was 4.5 tonnes over RTOW.

Another factor to emerge, probably non-contributory, was that the FO's medical had expired, hence his licence was invalid, hence the aircraft was being operated without a fully-qualified crew and hence not in accordance with its certification.

[ 06 September 2001: Message edited by: BEagle ]

[mcdhu]

Blimey days!! Just watched Capt John Hutchison put the boot in on BBC's breakfast TV. In the context of tonight's Conc documentary, when asked what he thought the cause was, he mentioned, in no uncertain terms, the missing spacer, the F/O's medical's expiry, the taxi fuel+19 bags leading to the ac being over max structural, and the tailwind accounting for a further 4T or so over RTOM, as contributary factors. Don't suppose AF will be inviting him to their re-inaugural bash!
Thanks to all for dragging this thread back to the sort of debate we should be having in this forum.
Cheers
mcdhu

[Mick Stability]

All the discussion about the aerodynamics of the crash is like talking over the arrangement of the deck chairs on the Titanic. The aircraft was too heavy to fly, too slow, and with insufficient thrust.

At the point of lining up the Captain appears to have been in possession of enough information to enable him to determine that take-off was unsafe, and yet he took the decision to proceed. That's it.

[New Bloke]

Thank you Enginefailure. I think someone before (and far more eloquently than me) has said in effect that we can analyse up to the point of departure all we like but from the moment they took the emergency into the air there is no point in any of this idle speculation. For that is all that it is, Jacko asks should Marty have stayed at 100’ rather than climb to 200’? Really, have you every flown at 100’?, if the flight deck was at 100’ think what height the tail would be, think how close to a tree or other obstruction that would be. It is quite possible that by staying at 100’ he would have impacted earlier.

So far we have criticised the last actions of a dead FE a Dead Captain and I suspect very soon we will start on the FO.

PLEASE, what can we learn from dissecting these last desperate minutes? The signal to shut down engine 2 COULD have been visual but that is as speculative as anything else on this thread. The only thing further speculation on the FLIGHT action serves is some vicarious morbid fascination that I find unseemly.

[Jackonicko]

You may find it 'unseemly' to question anything that happened after TO or to question the actions of the crew. I don't pretend for a moment that I could have done better, but do suspect that some sharp operators out there might have made better judgement calls, both before the aircraft taxied out, before it turned onto the runway, and afterwards.

I regret that we know the names of the crew - which makes it all look very 'personal' (uncomfortably so) and even that we know it was an AF aircraft (which has led to accusations of Francophopbia).

But it's highly contentious to state that they were doomed from rotate, or the No.2 engine being shut down, or whatever. It's a theory - and one supported by some stronger arguments than the theory that they might have made it.

But in asking the questions I have done about making the turn when they did, and climbing as they did, I'm just clawing for understanding, and trying to get it straight in my own mind, and rather than abusing me, please just explain why I'm wrong in thinking that the crew's first priority in any emergency situation should be to attempt to attain (and then maintain) the minimum safe speed for the configuration, and that climbing (especially over billiard table flat arable land) is a secondary consideration.

We know what Vzrc 2 and Vzrc 3 were, we know what VMCA was with the gear down, and we know what speed the aircraft was achieving, and we know that the aircraft also achieved a modest rate of climb.

Similarly, the question about when the turn towards Le Bourget was made is valid (distasteful, perhaps). Had a decision been made to turn earlier, that turn could have been gentler, and shallower. In the steeper, tighter turn that was attempted, the aircraft departed (perhaps due to pilot loss of control, perhaps because of control damage). Would it have departed had the turn been made earlier (less fire damage and less angle of bank required). There were 18 seconds between point 6 (over the motorway, with it noted that the gear wouldn't retract, knowing they were on fire, with the No. two engine confirmed as having been shut down, and with Le Bourget about 25° off the nose) and point 7, where they began to turn (with Le Bourget 50° off the nose). This is to say nothing of the fact that by failing to turn towards Le Bourget, they continued flying directly towards the built-up area of the town of Gonesse, whereas by turning early, they would have remained over open farmland.

And that is why talking about what went on after take off is important. That, if you like, is the point. There may be lessons to learn here, unless we can say hand-on-heart, that maintaining airspeed and bolting for Le Bourget would not have been even worth considering, and that the Captain showed judgement of the highest order.

It's not about impugning the man - in that situation, perfect judgement was unlikely to have been possible, but it is only by analysing what he might have done better that the next poor sap who finds himself in a similar position might be able to make a better, more informed judgement.

Or am I talking b0ll0cks again?

[ORAC]

Beagle, Jacko.

Correct me if I am wrong. As I understand it, Concorde crashed because it lost 2 engines with the undercarriage stuck down just after take-off in the low-speed regime. Once the second engine was lost, the remaining available thrust could not have saved the aircraft, even if there was no structural failure.

The circumstances of the FOD, tank rupture, fire etc just happened to be the failure mode that - on this occasion - caused the failure. That failure mode has now been addressed.

My question is - are there any other failure modes which could result in the same configuration again? How well, for example, is the tandem engine configuration protected against an uncontained engine failure and collateral damage to the undercarriage (even with armoured pipes)? How well is the wheel area protected against a major bird strike on the two engines. ( Remember the E3A at Elmendorf?)

Igonorance on my part. Maybe there are no other failure modes leading to the same result as they were all considered and eliminated during design (like this one - not)- but it would be nice to know.

[Reichman]

Harking back to BEagles "Back to basics" reply. It seems to me (please tell me if I'm wide of the mark here) that a long chain of events lead to the crash of this aircraft:

A missing spacer
An overweight take-off
A tailwind
FOD on the runway
Rotating below Vr
Not acheiving V2
A catastrophic fire
An undemanded engine shut down

Removing one or more of the above links might have lead to a different outcome - it might not

[ 06 September 2001: Message edited by: Reichman ]

[Seat 32F]

Am I right in thinking that (although they may not necessarily have been causal factors to the accident itself) these combinations of excessive take off weight, the questionable maintenance aspects of undercarriage, non availability of a thrust reverser together with (presumably) the knowledge that the runway had not been swept would cause some pilots here on the forum to think twice about the wisdom of proceeding with the flight - on the basis that several links in a possibly nasty chain of events are already evident before take-off? eg "We're too heavy, we've got a dodgy undercarriage and the runway hasn't been swept."

If this was you, would you permit commercial pressure to over-ride your judgement?

I asked this question before when we were discussing the SQ009 accident last year: if there had been a mandatory and documented risk assessment procedure that had to be signed-off before the flight departed, would it have changed the course of events?

I'd be interested to know just how many major incidents are the cumulative effect of too many 'we'll probably get away with it' type decisions.

(edited for punctuation purposes)

[ 06 September 2001: Message edited by: Seat 32F ]

[Capt PPRuNe]

Justa 'heads up' that this thread is about to reach the 100 post mark and will be closed soon. Any restart to this thread WILL be moved to the Tech Log forum.

[New Bloke]

Okay just time for me to say to Jacko that I did not abuse you anywhere in my reply. To re-state what I find unseemly. Picking over the crew's actions during the FLIGHT and only that. You are not talking bollox in asking questions about what happened and a lot of people (me included) seem to think that questions NEED to be asked about the crew's PRE-FLIGHT decision making. But to keep banging on about how the Captain should have not climbed to 200' shows (in my view) a lack of compassion. What do you want Jacko? Do you want a Concorde Pilot to reply saying you are right?

I have flown (in a Cessna 152) at 100' @ 70kts and I can tell you it is scarey. Try it in a flight deck that is (I'm guessing here) 80' higher than the tail, now try it in an unresponsive alight Aircraft with 100 sreaming people behind you.

I did not attack you Jacko, I just think the constant banging on about the split second decisions made that day show little respect for the crew.

[exeng]

New Bloke,

your statement, <I just think the constant banging on about the split second decisions made that day show little respect for the crew>

I am in agreement.


Regards
Exeng

[Al Weaver]

"My question is - are there any other failure modes which could result in the same configuration again? How well, for example, is the tandem engine configuration protected against an uncontained engine failure and collateral damage to the undercarriage (even with armoured pipes)? How well is the wheel area protected against a major bird strike on the two engines. ( Remember the E3A at Elmendorf?)"

Most big-iron aircraft that fly today have risks associated with the "what-ifs" you pose above. These risks are addressed by the design regulations under part 25 and part 33 that presume mitigating factors are present in the design. The regulations were preceded by the design of the Concorde, however important precedent setting design conditions were imposed on the Concorde to address these risks in an even more thorough fashion than the more general regulations of today.

As in most cases following an accident some weaknesses and vulnerability may be found in hindsight, that were not obvious in the initial design assumptions, however stringent they might have been.

[Evo7]

I've just read a rather disturbing piece on BBC News claiming a 1 in a billion chance for another Concorde accident. The story is at
http://news.bbc.co.uk/hi/english/uk/newsid_1528000/1528972.stm

Presumably this is just the BBC reporter being sloppy and they are referring to the particular accident, but quoting these sort of odds fills me with disbelief. I remember very well NASA quoting a million to one chance of a catastrophic Shuttle failure, shortly followed by Challenger exploding. Richard Feynmann took a rather independent view of that one and estimated 1 in 100.

Good BBC2 programme too, IMHO.

[Jackonicko]

New Bloke

(Yes, have flown at 100 ft, both rotary overland and fast and fast/heavy jet overwater. Not going to admit to 100 ft overland, even if I had, am I?).

"But to keep banging on about how the Captain should have not climbed to 200' shows (in my view) a lack of compassion. What do you want Jacko? Do you want a Concorde Pilot to reply saying you are right?"

No, I'm just interested in people's opinions in what they'd have done in these or similar circumstances. I'm fascinated that you, for instance, would have clawed for altitude at the expense of airspeed. I'd have been ruled by attitude (the horizon in the screen) and airspeed but then (like you, I guess) I'm just a PPL. I'm genuinely interested in what the pros would concentrate on - airspeed or altitude.

And in my book, compassion and respect for the dead isn't quite as important in learning lessons that might save lives - particularly since I know that I have enormous sympathy for the crew and the passengers.

[Covenant]

Jacko

The problem I have with your current position is that it assumes that the pilot was intentionally trading airspeed for altitude. That it something no one will ever know, so no matter how long you keep asking the question, you will never get an answer, at least not one that should satisfy your journalistic integrity.

For what it's worth, my opinion is that for most of the time, Marty was successfully performing a very delicate balancing act and maintaining approx. 200 ft at approx 200 kts. Had all things remained equal, I am confident that he would have been able to put Concorde down in Le Bourget in a more or less controlled manner.

Sadly they didn't, and what happened after that was, I believe, not related to his control input, but to further degradation in the aircraft's performace from whatever cause (and there are many candidates).

To continue to ask what other pros would do in that situation may eventually elicit and answer, but if it does, the answer should be treated with scepticism. No one know what they would do in that situation because no one really knows exactly what that situation was. I am convinced that something happened to make a difficult but stable situation suddenly very unstable and ultimately unrecoverable. I am also convinced that, whatever it was, it was outside the sphere of influence of the pilot.

If we were concerned with "what ifs", maybe we could still ask what would have happened if the FE had not shut down #2 engine... but that's another story (and, I'm sure, another long thread! :))

[edited for the inevitable typo]

[ 07 September 2001: Message edited by: Covenant ]

[Capt PPRuNe]

This one is at 100 posts it is being closed for technical reasons. I will archive it in the Tech Log archive.

Anyone wanting to continue the thread in a Mk II version please do so in the Tech Log forum.