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CONCORDE ACCIDENT - PART 2

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CONCORDE ACCIDENT - PART 2

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Old 5th Sep 2001, 23:31
  #81 (permalink)  
 
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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 ]
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Old 5th Sep 2001, 23:47
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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.
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Old 6th Sep 2001, 04:26
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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!!
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Old 6th Sep 2001, 11:24
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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 !
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Old 6th Sep 2001, 11:55
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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 ]
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Old 6th Sep 2001, 12:06
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Unhappy

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
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Old 6th Sep 2001, 12:51
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Red face

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.
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Old 6th Sep 2001, 12:52
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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.
 
Old 6th Sep 2001, 13:26
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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?
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Old 6th Sep 2001, 20:03
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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.
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Old 6th Sep 2001, 20:20
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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 ]
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Old 6th Sep 2001, 20:31
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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 ]
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Old 6th Sep 2001, 20:36
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Exclamation

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.
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Old 6th Sep 2001, 21:47
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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.
 
Old 6th Sep 2001, 22:00
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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
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Old 7th Sep 2001, 00:26
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"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.
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Old 7th Sep 2001, 01:04
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Unhappy

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/...00/1528972.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.
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Old 7th Sep 2001, 02:42
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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.
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Old 7th Sep 2001, 20:45
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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 ]
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Old 8th Sep 2001, 03:57
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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.
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