Concorde's Take Off Performance Falsified?
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I'm sure that loosing half your payload of fuel out of only one side of the aircraft would have contributed further regardless of the thrust issue. The imbalance would have had to be corrected with the elevons as tons of fuel poured out with increased drag screwing things up further. There comes a point I'm sure that you can't do any more no matter how much thrust you've got.
I think it should be applauded that the pilot and Concorde stayed up as long as they did rather than some sceptic bleating on and waving a slide-rule about. <img src="mad.gif" border="0">
I think it should be applauded that the pilot and Concorde stayed up as long as they did rather than some sceptic bleating on and waving a slide-rule about. <img src="mad.gif" border="0">
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I was never qualified for 3-engine ferries on the 747-400. If one of the select group of aviators who are is on the forum could they please put up some details of weights speeds, and technique.
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OK Guys, lets get away from the slanging match and the fact the the RAF may get more simulator time than civilians and look at a few facts.
The MD11 "expert" would perhaps like to try his airplane at MTOW with the gear stuck down, one engine out and T/O flap extended, with out losing a second engine. Losing hydraulics for the controls would add another factor that would not help. Although the three engines against four issue will be a factor.
Also as Gemini has only had MD11's for about two years and has only been in existance for three and he is an F/O must show something but then I am doing the slanging now!!
As one of the few Americans that was qualified on the VC10, it will indeed fly away on two at MTOW, BUT, only IF "everything" is in your favor. By thatI mean wind/temp./density alt/obstructions/pilot technique etc. PLUS of course that the Flying Pilot asks for the gear to be raised and/or the Non Flying Pilot does indeed raise the gear. So leave the Engineer screwing up part out of it, Beagle, pilots are not the almighty even if you are RAF! Actually if the two pilots forget I daresay, even in the RAF, the F/E would remind you to do it,if you would listen!
I also note the the publication that printed the letter is one of the "great" aviation magazines??
The A/F Concorde guys did their very best with what they were given and do not need to be outguessed by Monday Morning Quarterbacks.
If the airplane had rearview mirrors they might have been a bit better off but that is not reality.
The MD11 "expert" would perhaps like to try his airplane at MTOW with the gear stuck down, one engine out and T/O flap extended, with out losing a second engine. Losing hydraulics for the controls would add another factor that would not help. Although the three engines against four issue will be a factor.
Also as Gemini has only had MD11's for about two years and has only been in existance for three and he is an F/O must show something but then I am doing the slanging now!!
As one of the few Americans that was qualified on the VC10, it will indeed fly away on two at MTOW, BUT, only IF "everything" is in your favor. By thatI mean wind/temp./density alt/obstructions/pilot technique etc. PLUS of course that the Flying Pilot asks for the gear to be raised and/or the Non Flying Pilot does indeed raise the gear. So leave the Engineer screwing up part out of it, Beagle, pilots are not the almighty even if you are RAF! Actually if the two pilots forget I daresay, even in the RAF, the F/E would remind you to do it,if you would listen!
I also note the the publication that printed the letter is one of the "great" aviation magazines??
The A/F Concorde guys did their very best with what they were given and do not need to be outguessed by Monday Morning Quarterbacks.
If the airplane had rearview mirrors they might have been a bit better off but that is not reality.
To be pedantic, if the VC10 has suffered a double engine failure with the landing gear down, the drill is not to raise it! So if the FP asks for the gear to be selected up, that call would certainly be challenged by the other pilot and by the FE! It's because the doors opening into the airflow will cause even more drag than if the gear is stuck down.....just when the last thing you want is any more drag. Also, the subsequent loss of hydraulics could well cause some of the landing gear to adopt a 'Grand Old Duke of York' position - neither up nor down!!
Sorry, FEs, I am most certainly not having a 'generic' dig at you guys as I really value your part in our crews. A dig, however, at any company whose CRM seemingly allows uncommanded engine shut downs. And finally, yes, pilots are indeed not almighty
Sorry, FEs, I am most certainly not having a 'generic' dig at you guys as I really value your part in our crews. A dig, however, at any company whose CRM seemingly allows uncommanded engine shut downs. And finally, yes, pilots are indeed not almighty
A fascinating debate, although I'm sorry to say that I know little about the VC10 and less about the Concorde, from a professional level.
However, I would comment that suggestion that certain radical manoeuvres are flown in the sim, may be meaningless. Sims are designed to accurately simulate middle-of-the-envelope handling, they will extrapolate happily to all sorts of corners of the handling envelope, but this is rarely on the basis of actual flight test data.
Far too often something happens, and you later read "30 pilots all tried to achieve this in the sim, but couldn't, so the pilot in the actual case was superhuman", which is complete sphericals. The sim was probably not accurately representing what happened - because to do so somebody would have to go and obtain meaningful FT data. And, quite honestly, very few test pilots are that daft.
G
However, I would comment that suggestion that certain radical manoeuvres are flown in the sim, may be meaningless. Sims are designed to accurately simulate middle-of-the-envelope handling, they will extrapolate happily to all sorts of corners of the handling envelope, but this is rarely on the basis of actual flight test data.
Far too often something happens, and you later read "30 pilots all tried to achieve this in the sim, but couldn't, so the pilot in the actual case was superhuman", which is complete sphericals. The sim was probably not accurately representing what happened - because to do so somebody would have to go and obtain meaningful FT data. And, quite honestly, very few test pilots are that daft.
G
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EASY! Hand Solo. This is not a American vs. British thread. Fact is that the Americans and the British figure performance differently. It has been ten years since I did a comparison of the two and Im sorry I cant say more, but I do remember that each system had its good points. In fact , after being taught the differences, I wondered why someone didnt combine the two and come out with a superior product.
I am now Y2 compliant !
I am now Y2 compliant !
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To provide an example of Ghengis' point.
Some years ago I was involved in exploring the options in a Sea King post tail rotor failure. We found, in the sim, that it was perfectly possible starting from a 40' hover to pull pitch, climb vertically while ignoring the violently spinning visuals to 2000', then shut down the engines and execute a successful EOL. Curiously, we never wrote this technique up as advice to crews. <img src="eek.gif" border="0"> <img src="wink.gif" border="0">
Some years ago I was involved in exploring the options in a Sea King post tail rotor failure. We found, in the sim, that it was perfectly possible starting from a 40' hover to pull pitch, climb vertically while ignoring the violently spinning visuals to 2000', then shut down the engines and execute a successful EOL. Curiously, we never wrote this technique up as advice to crews. <img src="eek.gif" border="0"> <img src="wink.gif" border="0">
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It is a diversion from the main topic but Flap 5 raised some questions that, because they were so pointed, should receive answers.
It is curious to know why Scientific American has used information from a First Officer with a minor carrier
They didn't.
are we missing something here?
It seems.
Does this chap have knowledge and experience beyond his rank?
I'll let you pilots hash that out. The quoted item does not indicate knowledge of material factors in the accident but it may have been edited.
Could they not find someone more experienced and knowledgeable?
They could have but they weren't looking for anybody.
I fear that the answer goes back to the days when Concorde first flew and the American authorities made every effort to keep it out, because it had not been made by an American company.
Fear not.
This article seems to be another crude attempt to discredit Concorde
Nope - it was not an article.
and it is all the more surprising in such a reputable magazine.
Nope. Scientific American has a section called "News Scans" in which they report on items in the news that pertain to technology or science. In that section a few months ago they ran a positive news item on the return of the Concorde.
What was quoted here, essentially in its entirety, was a brief letter to the editor. The letter was critical of Scientific American's article. That would have been clear had the first few words of the letter been included but they were probably snipped because there would have been no context in PPRuNe. The editors of Scientific American perhaps felt that it was only fair play to air an opposing viewpoint. As usual, editors do not endorse the opinions of their readers even though they publish them.
In Scientific American the authors of major articles get a chance to rebut any readers' letters that are published. I do not think the authors of News Scans items get that opportunity and, Agaricus bisporus, it doesn't seem likely that you will either. Since the journal does not vouch for the opinions of its readers they have no reason to correct them.
It is curious to know why Scientific American has used information from a First Officer with a minor carrier
They didn't.
are we missing something here?
It seems.
Does this chap have knowledge and experience beyond his rank?
I'll let you pilots hash that out. The quoted item does not indicate knowledge of material factors in the accident but it may have been edited.
Could they not find someone more experienced and knowledgeable?
They could have but they weren't looking for anybody.
I fear that the answer goes back to the days when Concorde first flew and the American authorities made every effort to keep it out, because it had not been made by an American company.
Fear not.
This article seems to be another crude attempt to discredit Concorde
Nope - it was not an article.
and it is all the more surprising in such a reputable magazine.
Nope. Scientific American has a section called "News Scans" in which they report on items in the news that pertain to technology or science. In that section a few months ago they ran a positive news item on the return of the Concorde.
What was quoted here, essentially in its entirety, was a brief letter to the editor. The letter was critical of Scientific American's article. That would have been clear had the first few words of the letter been included but they were probably snipped because there would have been no context in PPRuNe. The editors of Scientific American perhaps felt that it was only fair play to air an opposing viewpoint. As usual, editors do not endorse the opinions of their readers even though they publish them.
In Scientific American the authors of major articles get a chance to rebut any readers' letters that are published. I do not think the authors of News Scans items get that opportunity and, Agaricus bisporus, it doesn't seem likely that you will either. Since the journal does not vouch for the opinions of its readers they have no reason to correct them.
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An interesting thread, indeed. A couple of points, if I may ..
(a) I am not aware of any 3/4 engined aircraft which has been certificated on the basis of a dual failure during the early takeoff phase. In general, the weight penalty to permit this would be commercially non-viable.
However, there is an en-route requirement which looks at the situation of a second failure and perhaps this has caused some confusion. I suspect that the great majority of us who have flown 3/4-motored birds have done numerous local training exercises with the second failure occuring sometime typically in the third or fourth segment... energetically dumping, descending, re-configuring etc., with a sigh of relief when a shallow climb results ....
(b) There is a problem when people look at the published rules and then generalise. Two points are relevant...
(i) by agreement between the design organisation and the regulatory authority, the certification basis is frozen during the early design work up of a new Type. To do otherwise would be intolerable .. the certification goalposts would change position with each subsequent rulebook amendment.
(ii) it is not at all unusual for specific rules to be reworked for a specific certification exercise.
This usually arises where the aircraft has a problem meeting a particular requirement but the designer is able to negotiate some sensible horse trading with the authority on the basis of equivalent safety determinations to achieve a workable outcome. There are numerous examples of this.
One must refer to the SPECIFIC rules, at the particular issue, for a specific Type and, if you can get access to the variations, such determinations. Then you make any assessment of what was required and whether the design did or did not achieve that which was required.
In respect of the Concorde (and I have no specific knowledge of that design's certification) it would have been quite incredible if the performance rules had not been varied to accommodate the quite different aerodynamic characteristics of a delta when compared to the more conventional civil planforms for which the existing rules were developed.
The various airworthiness authorities may not get it right invariably. Mistakes can occur and not be picked up until later .. hence the various processes of certification reviews which have been imposed on some Types post introduction to commercial service. This appears to have been done in respect of the Concorde's tyre design and/or tank protection requirements following the accident.
Ladies and gentlemen, I do think that we have to rely on the airworthiness people having a reasonable degree of professional integrity ...
[ 02 January 2002: Message edited by: john_tullamarine ]</p>
(a) I am not aware of any 3/4 engined aircraft which has been certificated on the basis of a dual failure during the early takeoff phase. In general, the weight penalty to permit this would be commercially non-viable.
However, there is an en-route requirement which looks at the situation of a second failure and perhaps this has caused some confusion. I suspect that the great majority of us who have flown 3/4-motored birds have done numerous local training exercises with the second failure occuring sometime typically in the third or fourth segment... energetically dumping, descending, re-configuring etc., with a sigh of relief when a shallow climb results ....
(b) There is a problem when people look at the published rules and then generalise. Two points are relevant...
(i) by agreement between the design organisation and the regulatory authority, the certification basis is frozen during the early design work up of a new Type. To do otherwise would be intolerable .. the certification goalposts would change position with each subsequent rulebook amendment.
(ii) it is not at all unusual for specific rules to be reworked for a specific certification exercise.
This usually arises where the aircraft has a problem meeting a particular requirement but the designer is able to negotiate some sensible horse trading with the authority on the basis of equivalent safety determinations to achieve a workable outcome. There are numerous examples of this.
One must refer to the SPECIFIC rules, at the particular issue, for a specific Type and, if you can get access to the variations, such determinations. Then you make any assessment of what was required and whether the design did or did not achieve that which was required.
In respect of the Concorde (and I have no specific knowledge of that design's certification) it would have been quite incredible if the performance rules had not been varied to accommodate the quite different aerodynamic characteristics of a delta when compared to the more conventional civil planforms for which the existing rules were developed.
The various airworthiness authorities may not get it right invariably. Mistakes can occur and not be picked up until later .. hence the various processes of certification reviews which have been imposed on some Types post introduction to commercial service. This appears to have been done in respect of the Concorde's tyre design and/or tank protection requirements following the accident.
Ladies and gentlemen, I do think that we have to rely on the airworthiness people having a reasonable degree of professional integrity ...
[ 02 January 2002: Message edited by: john_tullamarine ]</p>
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I'm certainly no expert, but with all the hypothesising and analysing in this interesting thread, something made me think of the following;
If the *wing* is on fire then surely the "basic" aerodynamics of the airfoil have been compromised? Regardless of the fact that structurally there were problems, and a loss of thrust from the engine (s) caused a stall or loss of control, Mr Bernouli's principle must rely on there being air creating differences in pressure and thus - lift. But if air cannot flow over a wing, because it is engulfed in flames, don't we have a major factor missing from the equation?
Then a changing c of g, weight loss as the fuel burns/escapes and structural damage are also factors, not to mention loss of thrust, gear down, tailwind, AF 744 with dignitaries in view, wheel spacers missing, AD's not complied with, overweight (have I missed anything?)
Just a thought. Interested if this would be something taken into account?
If the *wing* is on fire then surely the "basic" aerodynamics of the airfoil have been compromised? Regardless of the fact that structurally there were problems, and a loss of thrust from the engine (s) caused a stall or loss of control, Mr Bernouli's principle must rely on there being air creating differences in pressure and thus - lift. But if air cannot flow over a wing, because it is engulfed in flames, don't we have a major factor missing from the equation?
Then a changing c of g, weight loss as the fuel burns/escapes and structural damage are also factors, not to mention loss of thrust, gear down, tailwind, AF 744 with dignitaries in view, wheel spacers missing, AD's not complied with, overweight (have I missed anything?)
Just a thought. Interested if this would be something taken into account?
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Gentlemen: (and very probably ladies):
I understand the group dynamic that drives all this theorising, but it is becoming a rerun of the endless speculation immediately post-accident.
The report is out. It has been exhaustively written by experts who have all the available facts to hand. Regardless of one's personal prejudices (and I am no Francophile) it is a fact that the BEA is a well-respected and very experienced organisation.
'SC crashed because there was not enough thrust to overcome the tremendous drag in the flight regime it was in. It departed controlled flight in exactly the manner expected of a slender delta in such circumstances.
These are unarguable facts, governed by well-used laws of physics.
There really is no point in theorising alternative modes of departure.
I grant that it is possible to come up lots of 'what if's and 'if only's relating to how the aircraft came to be in that situation, and I know many will continue to do so.
Can I just ask that if you feel the need to contribute to that kind of discussion you base your contributions on known facts rather than what popular rumour/your mate's theory says happened. (In short - read the report before you claim it is wrong/ a whitewash/whatever).
As for the claim that TSS stds were written around Conc's performance - I suggest whoever wrote this researches when the elements of TSS were written relative to the flight test programme.
Of course they are different to conventional requirements - could you apply conventional defns of Vs and Vb, for example, to a wing which can see an alpha increase of 16 or so degrees from cruise conditions without stalling?
Finally: Double engine failures. I haven't flown a VC10. I have flown 747s and Concorde and I can tell you that the Conc is markedly more capable of dealing with a dbl failure at V1 at RTOW than a 747 *BUT* in both cases the chances of a successful outcome are very very slim indeed. The conc has a very good likelihood of flying through a dual failure at 500' successfully, more so than a 747, but so what? That didn't happen at CDG.
Anyone care to contribute something new?
I understand the group dynamic that drives all this theorising, but it is becoming a rerun of the endless speculation immediately post-accident.
The report is out. It has been exhaustively written by experts who have all the available facts to hand. Regardless of one's personal prejudices (and I am no Francophile) it is a fact that the BEA is a well-respected and very experienced organisation.
'SC crashed because there was not enough thrust to overcome the tremendous drag in the flight regime it was in. It departed controlled flight in exactly the manner expected of a slender delta in such circumstances.
These are unarguable facts, governed by well-used laws of physics.
There really is no point in theorising alternative modes of departure.
I grant that it is possible to come up lots of 'what if's and 'if only's relating to how the aircraft came to be in that situation, and I know many will continue to do so.
Can I just ask that if you feel the need to contribute to that kind of discussion you base your contributions on known facts rather than what popular rumour/your mate's theory says happened. (In short - read the report before you claim it is wrong/ a whitewash/whatever).
As for the claim that TSS stds were written around Conc's performance - I suggest whoever wrote this researches when the elements of TSS were written relative to the flight test programme.
Of course they are different to conventional requirements - could you apply conventional defns of Vs and Vb, for example, to a wing which can see an alpha increase of 16 or so degrees from cruise conditions without stalling?
Finally: Double engine failures. I haven't flown a VC10. I have flown 747s and Concorde and I can tell you that the Conc is markedly more capable of dealing with a dbl failure at V1 at RTOW than a 747 *BUT* in both cases the chances of a successful outcome are very very slim indeed. The conc has a very good likelihood of flying through a dual failure at 500' successfully, more so than a 747, but so what? That didn't happen at CDG.
Anyone care to contribute something new?
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It would be too long and boring to go into depth here, but:
Dealing with DP Davies' quote: it is true that AT TIMES certification and development were going on side by side. Read no more into the comment than that - don't forget that this is still true for any type which operates outside the current norms. As an example, take the 777: ETOPS on service entry - the certification requirements for ETOPS on entry were being developed at the same time as the aircraft and while it was being certificated. Also, don't forget what happened when the GE90 proved incapable of passing the 'blade off' test.
The 747 didn't have manual reversion on the flt controls and the certification requirements would have been changed to reflect this.
This type of refining of the requirements while types are under development is common to the point of normality - concorde was no exception.
The quotes are largely paraphrased in order to make the book accessible to a wider audience and a certain amount of reading between the lines is required.
In terms of performance margins, TSS reqs exceed equivalent BCARs or whatever, and manoeuvre margins hugely so.I believe this is also noted in the same book. There are many areas where TSS is more restrictive, which should demonstrate that there was no conspiracy to fudge the requirements.
The numbers emphatically are not fudged, and the fact remains that SSC has larger performance margins than subsonic long-haul aircraft.
If only the man himself was still here to give us the whole chapter and verse.
PS TSS is not a secret document - it is available in the public domain for perusal. Unfortunately the only hard copy I know of is owned by BA and is NOT available to the public!
Dealing with DP Davies' quote: it is true that AT TIMES certification and development were going on side by side. Read no more into the comment than that - don't forget that this is still true for any type which operates outside the current norms. As an example, take the 777: ETOPS on service entry - the certification requirements for ETOPS on entry were being developed at the same time as the aircraft and while it was being certificated. Also, don't forget what happened when the GE90 proved incapable of passing the 'blade off' test.
The 747 didn't have manual reversion on the flt controls and the certification requirements would have been changed to reflect this.
This type of refining of the requirements while types are under development is common to the point of normality - concorde was no exception.
The quotes are largely paraphrased in order to make the book accessible to a wider audience and a certain amount of reading between the lines is required.
In terms of performance margins, TSS reqs exceed equivalent BCARs or whatever, and manoeuvre margins hugely so.I believe this is also noted in the same book. There are many areas where TSS is more restrictive, which should demonstrate that there was no conspiracy to fudge the requirements.
The numbers emphatically are not fudged, and the fact remains that SSC has larger performance margins than subsonic long-haul aircraft.
If only the man himself was still here to give us the whole chapter and verse.
PS TSS is not a secret document - it is available in the public domain for perusal. Unfortunately the only hard copy I know of is owned by BA and is NOT available to the public!
In any aircraft with paired engines, it has to be an assumption that the catestrophic failure of one engine would be likely to lead to the failure of the adjescant one. Of the two types I have flown with paired engines, we used that assumption and trained for it regularly - it was a tricky situation but one that was surviveable if the correct techniques were applied.
One of these was the VC10, which was originally certified for this situation. It happened to BOAC twice to my knowledge, both times the aircraft landed safely.
The DEFATO (Double Engine Failure After Take Off) drill in the VC10 sim was one of the most demanding things I have ever done, but regular practice was necessary IMHO.
One of these was the VC10, which was originally certified for this situation. It happened to BOAC twice to my knowledge, both times the aircraft landed safely.
The DEFATO (Double Engine Failure After Take Off) drill in the VC10 sim was one of the most demanding things I have ever done, but regular practice was necessary IMHO.
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Folks,
Jon Modrey, an MD11 FO with Gemini Air Cargo from Orlando, FLA has done most of us a favour.
He has demonstrated that assertions of aviation "fact" will be tracked down and debated at length on these fora.
I was a little surprised that no one brought up the fact that the FAA varied the performance requirements of the B767-300 due to Vs1g testing rather tyhan Vs testing and the fact that it would be commercially unfortunate if the "new" aeroplane looked like having worse/different numbers to the -200. Furthermore, the changes made to accommodate the B777 were not a reflection of aerodynamic differences such as faced by DGAC/CAAUK with slender delta and supersonics - perhaps that may have been a more fruitful question for Jon to pursue.
Most importantly, as a consequence of his writings, I now know the name of TSS, the existence of which I was aware. I am also happy to know that WOK's assertion: "In terms of performance margins, TSS reqs exceed equivalent BCARs or whatever, and manoeuvre margins hugely so...The numbers emphatically are not fudged, and the fact remains that SSC has larger performance margins than subsonic long-haul aircraft." is relatively easily verified and, I think, very unlikely to be found untrue.
For all of that, I must thank Jon and his letter to the editor.
PS Perhaps after Jon has read FAR 25 and its amendment history, plus the squillions of ADs and other supporting documents about compliance with that FAR, he might get the most politically controlled and manipulated regulator outside the old Communist blocs to test real knowledge of the certification requirements of the aircraft in which he apparently occupies an important seat.
Jon Modrey, an MD11 FO with Gemini Air Cargo from Orlando, FLA has done most of us a favour.
He has demonstrated that assertions of aviation "fact" will be tracked down and debated at length on these fora.
I was a little surprised that no one brought up the fact that the FAA varied the performance requirements of the B767-300 due to Vs1g testing rather tyhan Vs testing and the fact that it would be commercially unfortunate if the "new" aeroplane looked like having worse/different numbers to the -200. Furthermore, the changes made to accommodate the B777 were not a reflection of aerodynamic differences such as faced by DGAC/CAAUK with slender delta and supersonics - perhaps that may have been a more fruitful question for Jon to pursue.
Most importantly, as a consequence of his writings, I now know the name of TSS, the existence of which I was aware. I am also happy to know that WOK's assertion: "In terms of performance margins, TSS reqs exceed equivalent BCARs or whatever, and manoeuvre margins hugely so...The numbers emphatically are not fudged, and the fact remains that SSC has larger performance margins than subsonic long-haul aircraft." is relatively easily verified and, I think, very unlikely to be found untrue.
For all of that, I must thank Jon and his letter to the editor.
PS Perhaps after Jon has read FAR 25 and its amendment history, plus the squillions of ADs and other supporting documents about compliance with that FAR, he might get the most politically controlled and manipulated regulator outside the old Communist blocs to test real knowledge of the certification requirements of the aircraft in which he apparently occupies an important seat.
Moderator
R4D .... great to see you are still in the land of the living ... have you been on holidays ? ... and I trust that the day at the Bend went well.
Without checking my archives I cannot be certain as to just when it came in, but I suspect that the alternative stall demonstration requirement quite predated the 763 ?
Your main point .. that the pprune board promotes debate remains very valid .. I suspect that we all learn quite a lot from these pages.
Without checking my archives I cannot be certain as to just when it came in, but I suspect that the alternative stall demonstration requirement quite predated the 763 ?
Your main point .. that the pprune board promotes debate remains very valid .. I suspect that we all learn quite a lot from these pages.
The B747-400 can, at MTOW and up to about 30C, suffer an engine failure after V1 and then a further engine failure, on the same side, shortly after Vr and successfully climb away if the first thing you do is select flaps to 10 regardless of the speed. You will be below F10 manoeuver speed but you have to get rid of some drag and accelerate. If you persist with trying to fly with F20 still selected you probably make a very large black hole somewhere. Not a recommended procedure of course but if saves your ar$e one dark and dirty night who cares? <img src="eek.gif" border="0"> <img src="eek.gif" border="0">
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JT,
As you know, consultants don't have holidays, they just have interludes in the work programme! Unfortunately, I missed the Bend as one of ny VSCs (very significant client) required my presence elsewhere.
Yes, the change permitting Vs1g did predate the B763 but postdated the amendment applicable to the original TC. The problem may have been triggered by CAAUK certification requirements, I am not sure. In any case, those students of FAR 25 and its clones will find that the numbers do not add up - Boeing negotiated a slightly different set of ratios and margins with the good ole FAA.
As for the comments about what B744s will do - I think the main thrust of the topic was certification requirements, of which none that I am aware require guaranteed performance in the event of suffering a second engine failure during the take-off sequence if the risk assessment indicates that secondary damage is highly improbable.
As you know, consultants don't have holidays, they just have interludes in the work programme! Unfortunately, I missed the Bend as one of ny VSCs (very significant client) required my presence elsewhere.
Yes, the change permitting Vs1g did predate the B763 but postdated the amendment applicable to the original TC. The problem may have been triggered by CAAUK certification requirements, I am not sure. In any case, those students of FAR 25 and its clones will find that the numbers do not add up - Boeing negotiated a slightly different set of ratios and margins with the good ole FAA.
As for the comments about what B744s will do - I think the main thrust of the topic was certification requirements, of which none that I am aware require guaranteed performance in the event of suffering a second engine failure during the take-off sequence if the risk assessment indicates that secondary damage is highly improbable.
