Burst tyre behind Concorde crash-report
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Harvy,
"This" was not a problem that had been around for ages. "This" was a problem which had never surfaced before. It was a problem caused by a chain of many highly improbable events, starting with an incredibly unfortunately shaped strip of titanium which stripped the outer case off a tyre in a manner never seen before let alone forecast, leading to the loss of the aircraft. This had never happened before, and probably never would again irrespective of any modifications.
Each one of the indentifiable links in the chain have been addressed (their luck never recovered from encountering the strip: the mode of the fuel tank hole creation - the location and size of the hole etc. all were worst thing, worst time, worst place events)- yes: because a fatal accident occourred, but what happened at Paris that day was unique in Concorde's history. Claiming from your armchair that it was obvious or predictable as you do is facile and misleading.
To repeat: debris from a Concorde tyre has never puntured a fuel tank; it was an unprecented and unforcastable accident. All that web link you quote proves is just how resilient the Concorde type is to tyre failures.
"This" was not a problem that had been around for ages. "This" was a problem which had never surfaced before. It was a problem caused by a chain of many highly improbable events, starting with an incredibly unfortunately shaped strip of titanium which stripped the outer case off a tyre in a manner never seen before let alone forecast, leading to the loss of the aircraft. This had never happened before, and probably never would again irrespective of any modifications.
Each one of the indentifiable links in the chain have been addressed (their luck never recovered from encountering the strip: the mode of the fuel tank hole creation - the location and size of the hole etc. all were worst thing, worst time, worst place events)- yes: because a fatal accident occourred, but what happened at Paris that day was unique in Concorde's history. Claiming from your armchair that it was obvious or predictable as you do is facile and misleading.
To repeat: debris from a Concorde tyre has never puntured a fuel tank; it was an unprecented and unforcastable accident. All that web link you quote proves is just how resilient the Concorde type is to tyre failures.
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NW1 you have me at a disadvantage, Sir. I do not have the manuals and I do not operate the Concorde. My suspicions are raised because the report quotes the maximum capacity in litres as 119,280, with an approved overload of 1,630 litres giving a maximum of 120,910 litres.
The report quotes that standard Jet A1 with a sg of 0.792 was used to fill the aircraft, and the engineer quotes the gauges as reading 96.4 on the ramp before departure. 96.4 tonnes at 0.792 gives 121,717 litres, which is 807 litres or .807 cubic metres over the maximum capacity, hence it was overfilled.
The work that was done by the manufacturers on hydraulic shock quotes the rupture mechanism involved in a full tank with no air gaps. With this fuel load I suggest that not only was there no air gap, but no surge space available.
My information on fuelling came from an old acquaintance in Shell who described the procedure for high gravity fuels. Perhaps it was during development flying or something. You are probably well aware that jet fuel can come in a range of densities between .775 and 0.84, but DEF STAN 91-91 fuel which is the British standard for Jet A1 comes in at 0.793. However, higher density fuels, with a higher calorific value are available due to a higher napthalenes and aromatic content. These fuels (commonly 0.808) enable higher fuel loads to be carried and thus longer range flight. They tend to be less environmentally friendly with more smoke and more emissions.
If any of my assumptions about Concorde operations are incorrect, then I gladly give way to you. Perhaps in your rather unique position, you might tell us what maximum take-off weight you would use for CDG 26R with 080/09kt and 19ºC. Would you have operated your Concorde at that weight, 187.5 tonnes?
The report quotes that standard Jet A1 with a sg of 0.792 was used to fill the aircraft, and the engineer quotes the gauges as reading 96.4 on the ramp before departure. 96.4 tonnes at 0.792 gives 121,717 litres, which is 807 litres or .807 cubic metres over the maximum capacity, hence it was overfilled.
The work that was done by the manufacturers on hydraulic shock quotes the rupture mechanism involved in a full tank with no air gaps. With this fuel load I suggest that not only was there no air gap, but no surge space available.
My information on fuelling came from an old acquaintance in Shell who described the procedure for high gravity fuels. Perhaps it was during development flying or something. You are probably well aware that jet fuel can come in a range of densities between .775 and 0.84, but DEF STAN 91-91 fuel which is the British standard for Jet A1 comes in at 0.793. However, higher density fuels, with a higher calorific value are available due to a higher napthalenes and aromatic content. These fuels (commonly 0.808) enable higher fuel loads to be carried and thus longer range flight. They tend to be less environmentally friendly with more smoke and more emissions.
If any of my assumptions about Concorde operations are incorrect, then I gladly give way to you. Perhaps in your rather unique position, you might tell us what maximum take-off weight you would use for CDG 26R with 080/09kt and 19ºC. Would you have operated your Concorde at that weight, 187.5 tonnes?
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BUT these figures are not limitations - they are capacities given as guidelines for planning - the actual limit is when the refuel valves trip off, there are no operational limitations here and talk of wings being "inflated" by "over-fuelling" is misleading.
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My understanding of 'high level increment'(HLI) refueling as quoted in the UK operators refuel procedure, does allow for extra fuel to be added after the refuel valves have shut normally.
From memory the procedure was to individually open certain tank refuel valves but jumping a connector on the Fuel Qty Cmptr to earth.
The refuel manual then gave a specified qty of litres than can be added to that tank. Effectivly each tank was topped to 'FULL'.
This was an approved procedure, I am no longer involved in the Concorde,so can not comment if it is still used, but was most certainly was used especially on BGI sectors.
The refuel pad used by the ground engineer had columns for recording HLI refuel. <img src="eek.gif" border="0">
BUT these figures are not limitations - they are capacities given as guidelines for planning - the actual limit is when the refuel valves trip off, there are no operational limitations here and talk of wings being "inflated" by "over-fuelling" is misleading.
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My understanding of 'high level increment'(HLI) refueling as quoted in the UK operators refuel procedure, does allow for extra fuel to be added after the refuel valves have shut normally.
From memory the procedure was to individually open certain tank refuel valves but jumping a connector on the Fuel Qty Cmptr to earth.
The refuel manual then gave a specified qty of litres than can be added to that tank. Effectivly each tank was topped to 'FULL'.
This was an approved procedure, I am no longer involved in the Concorde,so can not comment if it is still used, but was most certainly was used especially on BGI sectors.
The refuel pad used by the ground engineer had columns for recording HLI refuel. <img src="eek.gif" border="0">
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Capn. PCock-
I don't mean to hold you to any disadvantage <img src="smile.gif" border="0"> - just to address a few incorrect assumptions you made with no disrespect at all intended. Being current on the type obviously helps!!
The fuel vent system on the Concorde cannot be "filled" because it terminates in a scanvenge tank which contains a pump which pumps either into tank 3 or else to atmosphere - either way the vent system is kept clear. It may be that the hydraulic shock effect would not have taken place if tank 5 had been less than full (speculation, obviously), but the only time this would be the case would be on a very short trip indeed. Concorde is by no means the only airliner to roll with more than one tank full - but as I say there is a proper vent system similar to most other types and there is no defined limitation on the fuel level. (other than the scavenge pump dumping excess onto the rear cargo loaders <img src="rolleyes.gif" border="0"> )
Out of interest, at the SG of 0.792 you mention the quoted max. tanks figure is 94740 - add the allowable 1200kgs of "HLI" (the "extra" fuel I alluded to) and you get a planned max fuel of 95940 - the allowable 2% guage inaccuracy alone would take that to 97850 let alone any small variations in actual SG, so no: from my experience I would not say the fuel quantity itself on board was questionable and certainly not out of limits (there being no operating limits on fuel level). As for the performance consideration - to answer your question - no pilot may take off overweight simple as that. Even ignoring T/O performance issues the max. structural TOW is 185,070kgs but my own opinion is that this had no effect at all on the outcome. Once tank 5 had a big enough hole to lose its 7 and a quater tonnes of fuel assymetrically at 100+l/sec from the left wing I suspect it was game over at any weight and the devastatingly destructive fire sealed it.
One last point - I gather that detailed analysis of the FDR showed that local W/V at lift-off was actually zero - the tower quoted 080/9 was probably a temporary change local to the anemometer, but as I say I think this is a detail which had no bearing on the accident. It is important that the root cause is addressed (it has been - most thoroughly) but, like you, I would stress that it certainly isn't on to pay lip service to limitations such as RTOW - its just that this issue in this case was irrelevant in that it had no bearing on the outcome, IMHO.
I don't mean to hold you to any disadvantage <img src="smile.gif" border="0"> - just to address a few incorrect assumptions you made with no disrespect at all intended. Being current on the type obviously helps!!
The fuel vent system on the Concorde cannot be "filled" because it terminates in a scanvenge tank which contains a pump which pumps either into tank 3 or else to atmosphere - either way the vent system is kept clear. It may be that the hydraulic shock effect would not have taken place if tank 5 had been less than full (speculation, obviously), but the only time this would be the case would be on a very short trip indeed. Concorde is by no means the only airliner to roll with more than one tank full - but as I say there is a proper vent system similar to most other types and there is no defined limitation on the fuel level. (other than the scavenge pump dumping excess onto the rear cargo loaders <img src="rolleyes.gif" border="0"> )
Out of interest, at the SG of 0.792 you mention the quoted max. tanks figure is 94740 - add the allowable 1200kgs of "HLI" (the "extra" fuel I alluded to) and you get a planned max fuel of 95940 - the allowable 2% guage inaccuracy alone would take that to 97850 let alone any small variations in actual SG, so no: from my experience I would not say the fuel quantity itself on board was questionable and certainly not out of limits (there being no operating limits on fuel level). As for the performance consideration - to answer your question - no pilot may take off overweight simple as that. Even ignoring T/O performance issues the max. structural TOW is 185,070kgs but my own opinion is that this had no effect at all on the outcome. Once tank 5 had a big enough hole to lose its 7 and a quater tonnes of fuel assymetrically at 100+l/sec from the left wing I suspect it was game over at any weight and the devastatingly destructive fire sealed it.
One last point - I gather that detailed analysis of the FDR showed that local W/V at lift-off was actually zero - the tower quoted 080/9 was probably a temporary change local to the anemometer, but as I say I think this is a detail which had no bearing on the accident. It is important that the root cause is addressed (it has been - most thoroughly) but, like you, I would stress that it certainly isn't on to pay lip service to limitations such as RTOW - its just that this issue in this case was irrelevant in that it had no bearing on the outcome, IMHO.
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Hi Maintroller,
You're absoultely right about HLI fuel. I alluded to it but didn't want to cloud the issue with detail. It is a fully authorised way of adding 1200kgs to the fuel load by changing the fuel shut-off system. But it doesn't compromise the vent system, and it doesn't "inflate" fuel tanks - the implication that the fuel tanks were being blown up by "overfuelling" them was misleading. There is no operating limitation on the fuel system to be exceeded by loading fuel.
You see many 747-400's with fuel venting from the wingtip vents as they taxi round corners on a long range sector. With fuel loads in excess of 90 tonnes on any type it takes very small percentage point variation in temperature, SG or gauging accuracies to result in a bit of harmless venting. The fuel systems on airliners is designed to cope - and Concorde is no exception, as I pointed out to Capn. PCock...... hope this helps.
You're absoultely right about HLI fuel. I alluded to it but didn't want to cloud the issue with detail. It is a fully authorised way of adding 1200kgs to the fuel load by changing the fuel shut-off system. But it doesn't compromise the vent system, and it doesn't "inflate" fuel tanks - the implication that the fuel tanks were being blown up by "overfuelling" them was misleading. There is no operating limitation on the fuel system to be exceeded by loading fuel.
You see many 747-400's with fuel venting from the wingtip vents as they taxi round corners on a long range sector. With fuel loads in excess of 90 tonnes on any type it takes very small percentage point variation in temperature, SG or gauging accuracies to result in a bit of harmless venting. The fuel systems on airliners is designed to cope - and Concorde is no exception, as I pointed out to Capn. PCock...... hope this helps.
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Pee Cock mate. I'm so wounded by your remarks !. .Specially the last one. How can you be so mean and cruel !!? Ouch !!. .If you're going to use French, at least do it properly. Your command of the language is an absolute shocker. Stick to English and I suggest you read what I said again as there most obviously was a lot of line distortion on the way to your brain.
NW1 comments, I hope, will maybe persuade you of what the real issue is and that's not paying a lip service to SOP's. If not, no one can save you.. .You've got your booking at the loopie farm.
NW1 comments, I hope, will maybe persuade you of what the real issue is and that's not paying a lip service to SOP's. If not, no one can save you.. .You've got your booking at the loopie farm.
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Does not the report fail to answer a number of crucial questions?
For example, the report findings include the following:
"The marks on the runway show the aircraft deviating to the left of in relation to the runway centreline."
In fact, earlier in the report is states the aircraft was 22.5 metres left of the runway centreline. Runway 26R is 45m wide!! There is a fairly simple calculation there that shows the aircraft was about to leave the paved surface. There is no way the aircraft should have been there with the damage it had at that point suffered unless the pilot mishandled it (unlikely) or perhaps the missing spacer on the left main landing gear bogie?
Yet the report states:
The spacer on the left main landing gear bogie had not been re-installed during. .replacement of the bogie on 17 and 18 July 2000. This omission did not contribute to the accident.
Why did they not test the effect of a missing spacer on a bogie with a disintigrated tyre?
The conclusions also state:
"The crew began aircraft rotation at the same time, at a speed of 183 kt, 15 kt. .before VR."
No crew would begin rotation this early without a compelling reason. Perhaps the reason was that he was about to depart from the paved surface, and according to a number of reports which have not surfaced in the BEA report, was heading towards a B--747 at the holding point for 08!
As a result of the early rotation, the aircraft never got anywhere near to the V2 of 220kts. The best they managed was 208kt and they got airborne at 201kt, 2kt above planned Vr I don't think many aircraft will catch up with their planned performance if they have a failure after V1 and get airborne twenty knots too slowly.
Why is there is no analysis of this in the report? They say
"Because of the lack of thrust and the impossibility of retracting the landing gear,. .the aircraft was in a flight configuration which made it impossible to climb or to gain speed."
And yet with such early rotation, they would have had a serious problem climbing even with the landing gear retracted. In fact first segment climb is scheduled with the landing gear down!!
This is such a detailed report with for example a full page devoted to the aircraft air conditioning system! And a couple of lines devoted to the aircraft being twenty knots too slow to ever have a hope in hell of successfully climbing away from an engine failure!!!
For example, the report findings include the following:
"The marks on the runway show the aircraft deviating to the left of in relation to the runway centreline."
In fact, earlier in the report is states the aircraft was 22.5 metres left of the runway centreline. Runway 26R is 45m wide!! There is a fairly simple calculation there that shows the aircraft was about to leave the paved surface. There is no way the aircraft should have been there with the damage it had at that point suffered unless the pilot mishandled it (unlikely) or perhaps the missing spacer on the left main landing gear bogie?
Yet the report states:
The spacer on the left main landing gear bogie had not been re-installed during. .replacement of the bogie on 17 and 18 July 2000. This omission did not contribute to the accident.
Why did they not test the effect of a missing spacer on a bogie with a disintigrated tyre?
The conclusions also state:
"The crew began aircraft rotation at the same time, at a speed of 183 kt, 15 kt. .before VR."
No crew would begin rotation this early without a compelling reason. Perhaps the reason was that he was about to depart from the paved surface, and according to a number of reports which have not surfaced in the BEA report, was heading towards a B--747 at the holding point for 08!
As a result of the early rotation, the aircraft never got anywhere near to the V2 of 220kts. The best they managed was 208kt and they got airborne at 201kt, 2kt above planned Vr I don't think many aircraft will catch up with their planned performance if they have a failure after V1 and get airborne twenty knots too slowly.
Why is there is no analysis of this in the report? They say
"Because of the lack of thrust and the impossibility of retracting the landing gear,. .the aircraft was in a flight configuration which made it impossible to climb or to gain speed."
And yet with such early rotation, they would have had a serious problem climbing even with the landing gear retracted. In fact first segment climb is scheduled with the landing gear down!!
This is such a detailed report with for example a full page devoted to the aircraft air conditioning system! And a couple of lines devoted to the aircraft being twenty knots too slow to ever have a hope in hell of successfully climbing away from an engine failure!!!
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Bally - I personally am sure that the cause of the accident was as stated: the metal FOD -> unique tyre shred event -> unique ('till then) hydraulic shock event -> massive hole -> massive leak -> massive fire was all as the analysis revealed, and that action has been taken to prevent its recourrence. I do agree that the deviation and u/c spacer issue is puzzling and not covered as deeply as you'd expect in the report.
But even if they'd managed to reject the takeoff and stop within the ED / land at Le Bourget / climb away at V2: with most of the back end (including flying control surfaces) burning away -I think the end result would have been little different. I feel that the focus of the accident report has quite rightly been on the CAUSE(S) of the accident so that it has been prevented from happening again.
That's what matters, IMO. Perhaps all airliner accidents should receive such thorough attention: grounding, diagnosis, corrective action, re-instatment?
But even if they'd managed to reject the takeoff and stop within the ED / land at Le Bourget / climb away at V2: with most of the back end (including flying control surfaces) burning away -I think the end result would have been little different. I feel that the focus of the accident report has quite rightly been on the CAUSE(S) of the accident so that it has been prevented from happening again.
That's what matters, IMO. Perhaps all airliner accidents should receive such thorough attention: grounding, diagnosis, corrective action, re-instatment?
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NW1
I think you are probably correct that in this case they were on a hiding to nothing....probably.
But suppose the tyre had failed and taken out an engine with no fire. They would still have crashed because the aircraft was too slow to achieve V2 with reduced thrust. The massive drag of a slow delta winged aircraft would have ensured that they could never have climbed, fire or no fire.
If they had climbed away they might have made Le Bourget or they might have crashed on clear ground saving some lives on the ground. The increased speed may have blown the fire clear of the airframe!
I'm not convinced that the crash was inevitable if the aircraft had taken off at the correct speed.
I know there are a lot of ifs and maybes there but why were they not investigated. Could it be that it easier to blame another airline's maintenance practices?
Surely all these issues should be addressed in a thorough report.
I think you are probably correct that in this case they were on a hiding to nothing....probably.
But suppose the tyre had failed and taken out an engine with no fire. They would still have crashed because the aircraft was too slow to achieve V2 with reduced thrust. The massive drag of a slow delta winged aircraft would have ensured that they could never have climbed, fire or no fire.
If they had climbed away they might have made Le Bourget or they might have crashed on clear ground saving some lives on the ground. The increased speed may have blown the fire clear of the airframe!
I'm not convinced that the crash was inevitable if the aircraft had taken off at the correct speed.
I know there are a lot of ifs and maybes there but why were they not investigated. Could it be that it easier to blame another airline's maintenance practices?
Surely all these issues should be addressed in a thorough report.
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Bally,
We are getting a little off-thread and into speculation here (that's why I tried - but failed (!)- not to dive in), but: the Olympus has shown itself highly resistant to FOD. In fact there are many instances of it swallowing far more than a chewed up tyre without a hiccup. During the post-crash research into the effects of fuel ingestion on the engine at takeoff thrust (including full reheat) they surged the test engine so badly during a particularly extreme "to destruction" experiment that the compressor stages were written off (I saw the video - it was very impressive!). They then put the damaged engine though many (about 20 from memory) start / takeoff / accel / decell / shut down cycles including fuel ingestion with not even a loss of thrust or a raised EGT - surprising even RR I think.
But even if it did, a propos your supposition about delta-wings, a Concorde three-engine climb out at max TOW shows a positive rate of climb right down to V2 minus 23 knots (incidentally, that figure is only 18 knots on a subsonic a/c to BCARs). So no, I don't agree with your comment about attaining the right speed (although it certainly and obviously made the situation more grave, it was critically grave in the first place) - I believe that aircraft crashed because it was so massively systemically damaged and was being consumed by an unprecedentedly huge fire.
[quote]I know there are a lot of ifs and maybes there but why were they not investigated. Could it be that it easier to blame another airline's maintenance practices?<hr></blockquote>If you mean AF's maintainance, I don't believe that was the claim or that it was indeed the fault. If you mean Continental because the metal dropped off their jet - I don't think that they are being made convenient scape-goats. Sure, if that metal strip hadn't been deposited then the crash wouldn't have happened, but that doesn't mean the blame and corrective action stopped there - the many links in the chain of events have all, at huge effort and expense, been addressed even though it was an accident which occoured in the face of infinitessimal odds in the first place.
Edited for typo...
[ 21 January 2002: Message edited by: NW1 ]</p>
We are getting a little off-thread and into speculation here (that's why I tried - but failed (!)- not to dive in), but: the Olympus has shown itself highly resistant to FOD. In fact there are many instances of it swallowing far more than a chewed up tyre without a hiccup. During the post-crash research into the effects of fuel ingestion on the engine at takeoff thrust (including full reheat) they surged the test engine so badly during a particularly extreme "to destruction" experiment that the compressor stages were written off (I saw the video - it was very impressive!). They then put the damaged engine though many (about 20 from memory) start / takeoff / accel / decell / shut down cycles including fuel ingestion with not even a loss of thrust or a raised EGT - surprising even RR I think.
But even if it did, a propos your supposition about delta-wings, a Concorde three-engine climb out at max TOW shows a positive rate of climb right down to V2 minus 23 knots (incidentally, that figure is only 18 knots on a subsonic a/c to BCARs). So no, I don't agree with your comment about attaining the right speed (although it certainly and obviously made the situation more grave, it was critically grave in the first place) - I believe that aircraft crashed because it was so massively systemically damaged and was being consumed by an unprecedentedly huge fire.
[quote]I know there are a lot of ifs and maybes there but why were they not investigated. Could it be that it easier to blame another airline's maintenance practices?<hr></blockquote>If you mean AF's maintainance, I don't believe that was the claim or that it was indeed the fault. If you mean Continental because the metal dropped off their jet - I don't think that they are being made convenient scape-goats. Sure, if that metal strip hadn't been deposited then the crash wouldn't have happened, but that doesn't mean the blame and corrective action stopped there - the many links in the chain of events have all, at huge effort and expense, been addressed even though it was an accident which occoured in the face of infinitessimal odds in the first place.
Edited for typo...
[ 21 January 2002: Message edited by: NW1 ]</p>
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NW1
Your knowledge is impressive, and I will not take issue with any of your points. However it still begs the question, why were these points not clarified by the BEA.
One little quote from the report.
"a gap of twenty-two metres between the aircraft and the runway centreline."
Which bit of the aircraft for goodness sake! The runway is only 45m wide. Does that mean the entire aircraft is on the grass? Or half the aircraft? Or none of it? They don't specify a reference point on the aircraft! This is a very amateur bit of investigating.
There is evidence that at this point the Concorde was heading towards an AF 747 (with the French president on board) and the captain had no choice but to rotate early.
If this is correct, then the aircraft was effectively out of control before getting airborne. This is a very serious issue and the accident report completely fails to address it or to make any recommendations to prevent it recurring. So due to the lack of attention to this very serious loss of directional control, I am left asking myself, was it due to the lack of a spacer in the undercarriage assembly, or was there another reason which has yet to be discovered. Is the next Concorde which experiences a tyre failure also going to veer of the runway?
The major problem I have with the report is that the French authorities were obstructive towards the AAIB. This is just begging for accusations of conspiracy. In my view, you would only try to hide things if you were afraid of what might be found or wanted to present a report which suited political ends rather than flight safety aims.
Your knowledge is impressive, and I will not take issue with any of your points. However it still begs the question, why were these points not clarified by the BEA.
One little quote from the report.
"a gap of twenty-two metres between the aircraft and the runway centreline."
Which bit of the aircraft for goodness sake! The runway is only 45m wide. Does that mean the entire aircraft is on the grass? Or half the aircraft? Or none of it? They don't specify a reference point on the aircraft! This is a very amateur bit of investigating.
There is evidence that at this point the Concorde was heading towards an AF 747 (with the French president on board) and the captain had no choice but to rotate early.
If this is correct, then the aircraft was effectively out of control before getting airborne. This is a very serious issue and the accident report completely fails to address it or to make any recommendations to prevent it recurring. So due to the lack of attention to this very serious loss of directional control, I am left asking myself, was it due to the lack of a spacer in the undercarriage assembly, or was there another reason which has yet to be discovered. Is the next Concorde which experiences a tyre failure also going to veer of the runway?
The major problem I have with the report is that the French authorities were obstructive towards the AAIB. This is just begging for accusations of conspiracy. In my view, you would only try to hide things if you were afraid of what might be found or wanted to present a report which suited political ends rather than flight safety aims.
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>The major problem I have with the report is that the French authorities were obstructive towards the AAIB. This is just begging for accusations. . of conspiracy. In my view, you would only try to hide things if you were afraid of what might be found or wanted to present a report which suited political ends rather than flight safety aims.<
I don't think that you have this all right. It was the French judicial system that caused the problems and not the French BEA investigators. It would be quite a stretch to accuse the jusdicial system of conspiracy when their objective was to find culpability to satisfy their constituents.
In the end you are quite right that this type of behavior is more politically suited than serving the objective of flight safety. On the other hand do you suppose that safety has not yet been achieved?
I don't think that you have this all right. It was the French judicial system that caused the problems and not the French BEA investigators. It would be quite a stretch to accuse the jusdicial system of conspiracy when their objective was to find culpability to satisfy their constituents.
In the end you are quite right that this type of behavior is more politically suited than serving the objective of flight safety. On the other hand do you suppose that safety has not yet been achieved?
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See my previous post Lompaseo. The crew lost control of the aircraft before it got airborne. The investigation has failed to recognise this as even being a problem far less finding reasons for it in order that future crews should not have to face similar problems.
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NW1, thank you for your comments from what is clearly an experienced view point. I accept your explanations of the capabilities of the tankage, and the ability of the fuel vent system to cope with over-pressure. I also am prepared to entertain that at the maximum fuel load, and the limit of gauge tolerance, a fuel indication of 96.4 is consistent with normal operation.
Let us then move away from the minutiae of the fuel system and settle perhaps on a maximum certificated fuel weight of 94.74 tonnes. The zero fuel weight is quoted on the CVR by the crew as 91.9 tonnes, and we are able to deduce from the tape that 800kgs were burnt on the way to the runway. That gives a working weight at the moment of line up of 185,840 kgs which is still over the structural maximum certificated weight of the aircraft of 185,075 kgs.
The events that followed during the take-off roll are notorious history, and I shall not discuss further here. The common factor in all accidents is a chain of events that leads to a catastrophe. Breaking any one of those links in that chain is the key to averting disaster.
In the light of what is given to us in the officially documented factual account of this terrible disaster, can we identify any point at which the crew might have made an informed and routine decision not to proceed? In my humble opinion there is, and I would put it to you that that decision should have been made. Without discussing the tragic mechanism for the loss of the aircraft, the whole thing should have been stopped before it ever began.
Wallabie, you have yet to add one single, reasoned argument that is germane to this discussion. Your tirade of personal abuse has no place on a professional pilots forum. My knowledge of French may not be perfect, but I would never have had to learn it if I did not operate frequently into parts of the World where it is routinely used for the control of air traffic. My exchanges with you are at an end. Au Revoir – Is that alright?
Let us then move away from the minutiae of the fuel system and settle perhaps on a maximum certificated fuel weight of 94.74 tonnes. The zero fuel weight is quoted on the CVR by the crew as 91.9 tonnes, and we are able to deduce from the tape that 800kgs were burnt on the way to the runway. That gives a working weight at the moment of line up of 185,840 kgs which is still over the structural maximum certificated weight of the aircraft of 185,075 kgs.
The events that followed during the take-off roll are notorious history, and I shall not discuss further here. The common factor in all accidents is a chain of events that leads to a catastrophe. Breaking any one of those links in that chain is the key to averting disaster.
In the light of what is given to us in the officially documented factual account of this terrible disaster, can we identify any point at which the crew might have made an informed and routine decision not to proceed? In my humble opinion there is, and I would put it to you that that decision should have been made. Without discussing the tragic mechanism for the loss of the aircraft, the whole thing should have been stopped before it ever began.
Wallabie, you have yet to add one single, reasoned argument that is germane to this discussion. Your tirade of personal abuse has no place on a professional pilots forum. My knowledge of French may not be perfect, but I would never have had to learn it if I did not operate frequently into parts of the World where it is routinely used for the control of air traffic. My exchanges with you are at an end. Au Revoir – Is that alright?
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There we go again... <img src="frown.gif" border="0">
after seeing this discussion moving away from needless hairsplitting over a few extra knots of wind and a few extra kilograms of fuel thanks to some technical day to day insights on Concorde, some of us apparently are going to refocus on the supposed overweight of Concorde once again...
. .According to some precise calculations made by our friend here above, the weight at the moment of line-up was 185,840kgs which according to him is still over the structural maximum certificated weight of 185,075 kgs by a full 765kg... <img src="eek.gif" border="0"> . .I do not feel the need to check these figures, as I trust they are 100% correct, but allow me to make some remarks to them:
-) The weight at line-up is found by deducting 800kg from the rampweight that day. Now, we already had the discussion about how (un)accurdate this rampweight is (an error of up to 3% is nothing unusual), but for which I have been called all sorts of names. . .Nevertheless, I dare to ask if we are really going to do the same thing once again by giving too much importance to the accuracy of given values like that of the 800kg of fuel? I mean, first of all, how accurate is the readout of a fuel dial on Concorde (2% seems acceptable), and secondly, is it purely coincidental or did the F/E rounded off the fuel burn to a value ending on dubble zero? You see, substracting something with a margin of error of at least 2% from something with a margin of error of 3% and then saying oops, we are 0.4% over the limits is just b******t; any physician will tell you the total margin of error in such a case is even more than 3%. In other words, Concorde could very well have been 0.4% overweight, or even 3%, but she might as well have been a full 3% below her max take-off weight!
-) We really have to start taking max. take-off weight (MTOW) for what it is; an indication of a limit rather then an absolute limit. The best prove that this is also the way manufacturers want you to think of it is found in their winter operations. As you maybe know winter operations require the removal prior to departure of all snow, ice and frost on aerodynamic surfaces like wings and tails, but most planes are certified to take-off with ice on the fuselage. Now, if we accept that ice deposit on the fuselage has a weight too (nothing unreasonable, is it?), then it is clear that any MTOW-departure under these icing conditions is actually nothing more than an overweight departure because there is no correction made on your loadsheet for the additional weight of the ice! Yet, although the mathematical outcome shows you an overweight situation, this is in fact OK for manufacturers like Airbus and Boeing. . .Now, if it is apparently OK to take-off with let's say MTOW + 700kg of ice on the fuselage, then are we really going to fool eachother by sitting at the holding point burning of an extra 700kg of fuel for 10 minutes?
You see, my moint is:. .you have to make a distinction between the planning and the operations phase of a flight.. .In the planning phase everybody should stick to all kind of limits, and if you exceed them by one knot, one feet or one kilogram, you should do something about it. . .However, the general philosophy is slightly different when in the operating phase (i.e. crew on board); knowing that all given limits still leave you with a considerable margin, then it is perfectly ok for a captain to use a small bit of this margin to stay in line with the economical criteria set forward by his company. This decision taking process of how much of a margin can be is used is called captaincy and comes not from books, but from experience. It differs from plane to plane and from pilot to pilot of course: I have seen guys with big margins (taking of with tailwinds of 10 knots when perfo was calculated with no wind) and guys with very small margins (asking to recalculate take-off data for an intersection take-off on a rwy you could reland on), yet I'd say 0.4% overweight certainly is no big deal...
after seeing this discussion moving away from needless hairsplitting over a few extra knots of wind and a few extra kilograms of fuel thanks to some technical day to day insights on Concorde, some of us apparently are going to refocus on the supposed overweight of Concorde once again...
. .According to some precise calculations made by our friend here above, the weight at the moment of line-up was 185,840kgs which according to him is still over the structural maximum certificated weight of 185,075 kgs by a full 765kg... <img src="eek.gif" border="0"> . .I do not feel the need to check these figures, as I trust they are 100% correct, but allow me to make some remarks to them:
-) The weight at line-up is found by deducting 800kg from the rampweight that day. Now, we already had the discussion about how (un)accurdate this rampweight is (an error of up to 3% is nothing unusual), but for which I have been called all sorts of names. . .Nevertheless, I dare to ask if we are really going to do the same thing once again by giving too much importance to the accuracy of given values like that of the 800kg of fuel? I mean, first of all, how accurate is the readout of a fuel dial on Concorde (2% seems acceptable), and secondly, is it purely coincidental or did the F/E rounded off the fuel burn to a value ending on dubble zero? You see, substracting something with a margin of error of at least 2% from something with a margin of error of 3% and then saying oops, we are 0.4% over the limits is just b******t; any physician will tell you the total margin of error in such a case is even more than 3%. In other words, Concorde could very well have been 0.4% overweight, or even 3%, but she might as well have been a full 3% below her max take-off weight!
-) We really have to start taking max. take-off weight (MTOW) for what it is; an indication of a limit rather then an absolute limit. The best prove that this is also the way manufacturers want you to think of it is found in their winter operations. As you maybe know winter operations require the removal prior to departure of all snow, ice and frost on aerodynamic surfaces like wings and tails, but most planes are certified to take-off with ice on the fuselage. Now, if we accept that ice deposit on the fuselage has a weight too (nothing unreasonable, is it?), then it is clear that any MTOW-departure under these icing conditions is actually nothing more than an overweight departure because there is no correction made on your loadsheet for the additional weight of the ice! Yet, although the mathematical outcome shows you an overweight situation, this is in fact OK for manufacturers like Airbus and Boeing. . .Now, if it is apparently OK to take-off with let's say MTOW + 700kg of ice on the fuselage, then are we really going to fool eachother by sitting at the holding point burning of an extra 700kg of fuel for 10 minutes?
You see, my moint is:. .you have to make a distinction between the planning and the operations phase of a flight.. .In the planning phase everybody should stick to all kind of limits, and if you exceed them by one knot, one feet or one kilogram, you should do something about it. . .However, the general philosophy is slightly different when in the operating phase (i.e. crew on board); knowing that all given limits still leave you with a considerable margin, then it is perfectly ok for a captain to use a small bit of this margin to stay in line with the economical criteria set forward by his company. This decision taking process of how much of a margin can be is used is called captaincy and comes not from books, but from experience. It differs from plane to plane and from pilot to pilot of course: I have seen guys with big margins (taking of with tailwinds of 10 knots when perfo was calculated with no wind) and guys with very small margins (asking to recalculate take-off data for an intersection take-off on a rwy you could reland on), yet I'd say 0.4% overweight certainly is no big deal...
Join Date: Sep 2001
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Sabenapilot your comments are the dumbest I've seen on this website.
You have NO idea what you are talking about so until you do shut the f$ck up. <img src="mad.gif" border="0"> <img src="mad.gif" border="0"> <img src="mad.gif" border="0">
You have NO idea what you are talking about so until you do shut the f$ck up. <img src="mad.gif" border="0"> <img src="mad.gif" border="0"> <img src="mad.gif" border="0">
