Did a BA B747 dump 50t of fuel due to a miscalculation?
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Did a BA B747 dump 50t of fuel due to a miscalculation?
I heard that a BA 747 had to dump 50 Tonnes fuel on a transit flight from LHR to CWL recently due to an "mis-calculation of the max landing weight " !!!
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Unlikely. If this took place at all, I would have thought that it was due to reassignment of a heavily fuelled aircraft to maintenance at Cardiff, or unexpected repairs needed. No 'miscalculation'. Between preparation of loadsheet and crew monitoring of take-off/landing weights, any miscalculation is impossible. It's not unknown for aeroplanes to very infrequently take-off knowing they will be exceeding max landing weight for a few limited reasons, relying on increased fuel burn through various methods to adjust to max landing weight. Jettison is not routinely an option.
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Well Ba always do computerised loadsheets, where all values are confirmed by crew. There is the possibility that the fuel order was misheard- this would be picked up. It's pretty obvious to a crew on a 25 minute delivery flight whether landing weight problems will be experienced. I believe possibilities for human error have been trapped there. Therefore I would expect some other explanation for this alleged (and as yet unconfirmed) incident, if indeed it took place at all!
Aviation stories are worse than old womens' gossip! I never believe anything now on the internet unless someone I trust confirms it. Especially stories circulated by people who are not closely involved. It's all generally garbage.
Aviation stories are worse than old womens' gossip! I never believe anything now on the internet unless someone I trust confirms it. Especially stories circulated by people who are not closely involved. It's all generally garbage.
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Aviation stories are worse than old womens' gossip! I never believe anything now on the internet unless someone I trust confirms it.
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Sounds like bolleaux to me. Given that a typical ZFW for a CWL flight is around 200T and MLW is around 285T you'd need to put about 145T of fuel on before you'd need to dump 50T to get down to MLW. Do you not think somebody would question why you needed 145T of fuel for a 100nm flight?
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BA
Anybody think about the possibility that the a/c was fuelled for a different flt and that the a/c was rescheduled for a CWL flt....tara there U hv the possibility that the a/c was overfuelled....like I always say... nothing is for sure in the airline bussiness
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Suppie, are you really saying that once fuel is on an aircraft the only way to get it off is either to burn it or pour it into the sea from a great height? As mere SLF, I find that hard to believe.
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No Suppie wasn't saying that at all.
Any jet transport can be de-fuelled, however it is a time consuming process and the fuel has to be stored and then re-used on another company aircraft (i.e it cannot be re-sold to another airline) This process is generally considered to be more expensive than just dumping it into the atmosphere.
By the way the minimum altitude for dumping on the 747 is (or at least used to be) 6000 ft except in dire emergencies. It is thought that at this altitude the kerosene will be dispersed into into extremely small droplets and not cause any hazards on land or sea. (Not too sure our tree hugging friends would entirely agree with this last statement)
Any additional costs due to fuel usage in this way is passed on to the customers by way of a fuel surcharge, amounts of which are arrived at after discussion with other interested parties such as Virgin Atlantic.
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Exeng
Any jet transport can be de-fuelled, however it is a time consuming process and the fuel has to be stored and then re-used on another company aircraft (i.e it cannot be re-sold to another airline) This process is generally considered to be more expensive than just dumping it into the atmosphere.
By the way the minimum altitude for dumping on the 747 is (or at least used to be) 6000 ft except in dire emergencies. It is thought that at this altitude the kerosene will be dispersed into into extremely small droplets and not cause any hazards on land or sea. (Not too sure our tree hugging friends would entirely agree with this last statement)
Any additional costs due to fuel usage in this way is passed on to the customers by way of a fuel surcharge, amounts of which are arrived at after discussion with other interested parties such as Virgin Atlantic.
Regards
Exeng
Last edited by exeng; 6th Aug 2007 at 22:51. Reason: Spelling
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"No 'miscalculation'. Between preparation of loadsheet and crew monitoring of take-off/landing weights, any miscalculation is impossible"
Surely "unlikely" would be more accurate than impossible.
The
rotation speed had been mistakenly calculated for an aeroplane
weighing 100 tonnes less than the actual weight of 9V-SMT. A take-off
weight transcription error, which remained undetected, led to the
miscalculation of the take-off data, which in turn resulted in a low
thrust setting and excessively slow take-off reference speeds. The
system defences did not ensure the errors were detected, and the
aeroplane flight management system itself did not provide a final
defence against mismatched information being programmed into it.
http://www.taic.org.nz/aviation/03-003.pdf
Surely "unlikely" would be more accurate than impossible.
The
rotation speed had been mistakenly calculated for an aeroplane
weighing 100 tonnes less than the actual weight of 9V-SMT. A take-off
weight transcription error, which remained undetected, led to the
miscalculation of the take-off data, which in turn resulted in a low
thrust setting and excessively slow take-off reference speeds. The
system defences did not ensure the errors were detected, and the
aeroplane flight management system itself did not provide a final
defence against mismatched information being programmed into it.
http://www.taic.org.nz/aviation/03-003.pdf
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Any sensible pilot on a plane for more than a few months knows the 'right' weights he should be seeing on a loadsheet, and a glance at the fuel figures is all that is needed. You point to errors that have occurred in this process- as far as I am aware it has not happened anywhere where I have flown. I think the system is sufficient, and any such errors are gross negligence.
So this thread rumours idiocy or serious error afoot in BA. I have just said I would like to see more evidence please. The reason would be far more likely late reassignment of a fuelled aeroplane to a 25 minute flight, but I'm afraid as pointed out, as it currently stands, there would be no circumstance I can see where such events as outlined here would happen. It would mean the 747 must have departed at max take-off weight for a 25 minute flight to Cardiff.
I simply say put up or shut up, but don't denigrate an innocent party with these nonsense rumours without anything substantial.
So this thread rumours idiocy or serious error afoot in BA. I have just said I would like to see more evidence please. The reason would be far more likely late reassignment of a fuelled aeroplane to a 25 minute flight, but I'm afraid as pointed out, as it currently stands, there would be no circumstance I can see where such events as outlined here would happen. It would mean the 747 must have departed at max take-off weight for a 25 minute flight to Cardiff.
I simply say put up or shut up, but don't denigrate an innocent party with these nonsense rumours without anything substantial.
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Well I would say my post, though not directly referring to BA, it was addressed to your statement of "any miscalculation is impossible", shows a miscalculation is quite capable of being perpetrated in the best of circles. Still believe "unlikely" would be more appropriate then "impossible". One could come up with many more examples if required.
Last edited by prospector; 7th Aug 2007 at 09:27.
fuel has to be stored and then re-used on another company aircraft (i.e it cannot be re-sold to another airline)
When I sold fuel, among other airport services, if we defueled (slow process, as someone pointed out) the stuff went back into the main storage, after contamination and quality (specification) checks, and was resold.
If the fuel failed the tests it was used for fire training, and obviously would not go into any aircraft, including the company from whence it came.
The only consideration was contamination and quality, because the aircraft tanks mixed fuel from many sources.
We charged the earth for all this, if we could do it at all when needed, which meant that very, very few aircraft were defuelled. Among other problems, you need a spare tanker or three on hand to receive and probably store the discharged fuel, at least until it can go back into the main storage.
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BA 757 operation to near Europe. My fuel requirement was around 10 tons but on arrival at the aircraft there was in excess of 20 tons in the tanks. Error? No! The aircraft had been at base following a fuel control valve change with an obvious engine run following the change.
There was a requirement for a minimum fuel level in the tanks even when doing ground runs. Perhaps (if it actually happened) this was a similar case.
When Blair (remember him) returned from the middle east a few years ago the 777 on shutdown had almost 40 tons in the tanks (management pilot). If that aircraft on its next sector had been on its way to Cardiff then there may have been a landing weight problem. There wasn't, I took it to Boston!
Back to the plot, whatever the reason (yet again assuming for a moment it actually happened) for the "extra" fuel loaded prior to departure the options would have been to dump when airborne or defuel. Defuelling takes ages and ages (aircraft tanks do not like negative pressure being applied to them) and, assuming that the fuel company can provide an empty bowser in the first place, the resultant fuel has to be returned to the refinery (Fawley in this case) for re-refining... All very expensive.
Let's have the facts (if it even happened).
There was a requirement for a minimum fuel level in the tanks even when doing ground runs. Perhaps (if it actually happened) this was a similar case.
When Blair (remember him) returned from the middle east a few years ago the 777 on shutdown had almost 40 tons in the tanks (management pilot). If that aircraft on its next sector had been on its way to Cardiff then there may have been a landing weight problem. There wasn't, I took it to Boston!
Back to the plot, whatever the reason (yet again assuming for a moment it actually happened) for the "extra" fuel loaded prior to departure the options would have been to dump when airborne or defuel. Defuelling takes ages and ages (aircraft tanks do not like negative pressure being applied to them) and, assuming that the fuel company can provide an empty bowser in the first place, the resultant fuel has to be returned to the refinery (Fawley in this case) for re-refining... All very expensive.
Let's have the facts (if it even happened).