Converted B747-400's - Achieving the Performance Parameters?
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Converted B747-400's - Achieving the Performance Parameters?
As part of some longer-term project planning I am trying to collate information on the actual, achieved performance levels of the 747-400 conversions to freighters - the -SF and -BCF.
Obviously the first converted airframes are now in scheduled revenue service, and a number of players have put a lot of cash (and faith) behind the concept of turning pax aircraft into freighters. Given the importance of this programme plus the competenece of the main players in the market, I have been surprised to hear recently from a couple of sources (who should know the business) that the early conversions are not living up to expectations in terms of useful, revenue payloads (against the 'pure' 747F) - and that one or two players are even reviewing whether to proceed with future options. Maybe someone is just putting a 'spin' on this situation for their own reasons, but is this really a case of smoke without fire?
Obviously the first converted airframes are now in scheduled revenue service, and a number of players have put a lot of cash (and faith) behind the concept of turning pax aircraft into freighters. Given the importance of this programme plus the competenece of the main players in the market, I have been surprised to hear recently from a couple of sources (who should know the business) that the early conversions are not living up to expectations in terms of useful, revenue payloads (against the 'pure' 747F) - and that one or two players are even reviewing whether to proceed with future options. Maybe someone is just putting a 'spin' on this situation for their own reasons, but is this really a case of smoke without fire?
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AFAIK, the conversions have not been certified to the higher max TOGW of the -400Fs. That alone will keep the range or payload well below that of the pure freighters. Also, unless the floor of the upper deck was cut back, the max height restrictions will be extended to 2-4 more pallet positions.
Anyone have any definitive specs on the conversions?
Anyone have any definitive specs on the conversions?
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Ohhh...I just can't help myself with these sorts of statements.....
The best conversion for a B747-400 freighter, is to convert it into a B747-300 freighter!!!
This has been a consistant line with the -400 with me...maybe you've noticed!
Cheers...FD
The best conversion for a B747-400 freighter, is to convert it into a B747-300 freighter!!!
This has been a consistant line with the -400 with me...maybe you've noticed!
Cheers...FD
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The BCF conversion is going just fine. I have heard big problems are looming with the Bedek/IAI conversion. Assuming the 400 that's being converted had the high gross weight (872,000lbs) then it's not an issue. The increased ZFW is accomplished via the mod. The upper deck is modified aft of the upper deck escape doors and the beams are removed and applicable wiring and controls are re-routed. So there is an increase in the number of full size pallets when compared to the 300.
There are some "soft" spots on the main deck so there is a slight payload issue, however, that's offset by a lower empty weight as there is none of the nose door hardware.
I do know of one 400 operator who had the Bedek conversion done and they are having a very hard time due to some weight issues. They can't market the aicraft and are looking at selling it.
There are some "soft" spots on the main deck so there is a slight payload issue, however, that's offset by a lower empty weight as there is none of the nose door hardware.
I do know of one 400 operator who had the Bedek conversion done and they are having a very hard time due to some weight issues. They can't market the aicraft and are looking at selling it.
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You don't have to be an aeronautical engineer to comprehend that a converted pax -400 will not carry the same load as the pure freighter. If it could then Boeing could shut down its -400F production line.
The converted airframe is heavier and more restrictive; quite obvious just by looking at the upper stretched deck, by looking at all the window plugs and by looking at all the deactivated pax doors. The typical payload "penalty" is from 8 to 15kgs [1000s], depending on specific modification certifications. Although, an exhorbitant fee can be paid to Boeing for "paper" recertification of higher payload cabability.
The converted airframe is heavier and more restrictive; quite obvious just by looking at the upper stretched deck, by looking at all the window plugs and by looking at all the deactivated pax doors. The typical payload "penalty" is from 8 to 15kgs [1000s], depending on specific modification certifications. Although, an exhorbitant fee can be paid to Boeing for "paper" recertification of higher payload cabability.
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You don't have to be an aeronautical engineer to comprehend that a converted pax -400 will not carry the same load as the pure freighter. If it could then Boeing could shut down its -400F production line.
The converted airframe is heavier and more restrictive; quite obvious just by looking at the upper stretched deck, by looking at all the window plugs and by looking at all the deactivated pax doors. The typical payload "penalty" is from 8 to 15kgs [1000s], depending on specific modification certifications. Although, an exhorbitant fee can be paid to Boeing for "paper" recertification of higher payload cabability.
I'd suggest you might want to do a little research first. Using Boeing's figures the 744F has a max structural payload of 112.6 Tons, while the BCF is 113.5 Tons. The 744F has a MTOW of 875,000 LBS while the BCF has a MTOW of 870,000LBS. You might want to look at http://www.boeing.com/commercial/747...00sf_prod.html to check your thoughts.
The converted airframe is heavier and more restrictive; quite obvious just by looking at the upper stretched deck, by looking at all the window plugs and by looking at all the deactivated pax doors. The typical payload "penalty" is from 8 to 15kgs [1000s], depending on specific modification certifications. Although, an exhorbitant fee can be paid to Boeing for "paper" recertification of higher payload cabability.
I'd suggest you might want to do a little research first. Using Boeing's figures the 744F has a max structural payload of 112.6 Tons, while the BCF is 113.5 Tons. The 744F has a MTOW of 875,000 LBS while the BCF has a MTOW of 870,000LBS. You might want to look at http://www.boeing.com/commercial/747...00sf_prod.html to check your thoughts.
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What we need are real world empty weights for the two versions, since variations in assumptions about configurations can produce very different payloads in the simplified, if not simplistic, one page executive summaries and sales brochures.
It makes no sense for a converted airframe, with a lower MTOW, to have a higher payload. None. Besides the previously mentioned remnants of passenger windows and exit doors, common sense tells us that Boeing would not add unnecessary weight when building freighters from scratch.
The nose door is the only weight penalty that pure freighter carries, and I am sure Boeing would be happy to build a 747F without it if a customer wanted it that way.
If there is a problem with the conversions it is probably optimistic/misunderstood empty weight estimates. Or to put it another way, too many MBAs and too little industry experience.
It makes no sense for a converted airframe, with a lower MTOW, to have a higher payload. None. Besides the previously mentioned remnants of passenger windows and exit doors, common sense tells us that Boeing would not add unnecessary weight when building freighters from scratch.
The nose door is the only weight penalty that pure freighter carries, and I am sure Boeing would be happy to build a 747F without it if a customer wanted it that way.
If there is a problem with the conversions it is probably optimistic/misunderstood empty weight estimates. Or to put it another way, too many MBAs and too little industry experience.
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I'd suggest you might want to do a little research first. Using Boeing's figures the 744F has a max structural payload of 112.6 Tons, while the BCF is 113.5 Tons. The 744F has a MTOW of 875,000 LBS while the BCF has a MTOW of 870,000LBS.
Maximum Payload:
248,300 lbs (112,630 kg)
Optional 273,300 lbs (123,970 kg) available with maximum takeoff-weight limitation
248,300 lbs (112,630 kg)
Optional 273,300 lbs (123,970 kg) available with maximum takeoff-weight limitation
So, the SF gives up AT LEAST 10 tonnes of payload (8%), plus the volume (16 cu. M) and range (7.8%) hits and reduced flexibility with the lack of nose door.
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Intruder....what you say is correct, but you left out part of the story. When you do the increased ZFW you have a corresponding reduction of the MTOW. So for short segmentst, say BLR-SIN where fuel isn't an issue, you do get increased performance. However, for normal segments, HKG-ANC, NRT-ANC the BCF will give you a slight payload increase.
There is another problem with any conversion. That's the floor. On the 744F there's no soft spots, it's all the same floor loading. On the BCF there are some "soft" spots that don't have the dame floor limits as the rest of the main deck.
There is another problem with any conversion. That's the floor. On the 744F there's no soft spots, it's all the same floor loading. On the BCF there are some "soft" spots that don't have the dame floor limits as the rest of the main deck.
I am current on the 744F.
From the ops manual:-
Maximum Taxi Weight 397,800*
Maximum Takeoff Weight 396,893
Maximum Landing Weight 302,092
Maximum Zero Fuel Weight 288,031**
* For zero fuel weight equal to 276,691 kilograms and above, maximum taxi
weight equals maximum takeoff weight at brake release plus 1360 kilograms, up to the maximum taxi weight.
** Applicable when the maximum takeoff weight at brake release is 367,863
kilograms or less. For takeoff weights at brake release above 367,863 kilograms and up to 394,625 kilograms, reduce maximum zero fuel weight linearly to 276,691 kilograms. For airplanes with a maximum takeoff weight at brake release above 394, 625 kilograms and certified up to 396,893 kilograms, maximum zero fuel weight remains at 276,691 kilograms.
No empty weight is quoted (as this is different for each aircraft) but the max payload is around 128T. Doing the maths from above, at a max ZFW of 288T there is around 79T of fuel available which gives a range of 6+ hours. The max reserve fuel to stay below MLW is ca. 14T.
This allows a 2 stop return from the Far East or one stop from (say) BKK to Europe depending on the season.
It is some years since I flew the pax. model but as I remember the MLW was considerably less and the MZFW the lower figure as above. Since the increase was, I believe, made by increasing the strength of the wing box and lower wing panels, I assume that the -BCF/-SF's MLW and ZFW is not increased by the freight conversion forever limiting it's payload to the stated maximum quoted above.
I don't know if any -Fs were certified at lower than the optional higher MTOW, it would seem unlikely anyone would have been foolish enough to limit it's potential by so doing. More likely that Boeing quotes the standard weight at the lower figure with an option to certify higher thus being able to charge $$$ for the paperwork exercise.
From the ops manual:-
Maximum Taxi Weight 397,800*
Maximum Takeoff Weight 396,893
Maximum Landing Weight 302,092
Maximum Zero Fuel Weight 288,031**
* For zero fuel weight equal to 276,691 kilograms and above, maximum taxi
weight equals maximum takeoff weight at brake release plus 1360 kilograms, up to the maximum taxi weight.
** Applicable when the maximum takeoff weight at brake release is 367,863
kilograms or less. For takeoff weights at brake release above 367,863 kilograms and up to 394,625 kilograms, reduce maximum zero fuel weight linearly to 276,691 kilograms. For airplanes with a maximum takeoff weight at brake release above 394, 625 kilograms and certified up to 396,893 kilograms, maximum zero fuel weight remains at 276,691 kilograms.
No empty weight is quoted (as this is different for each aircraft) but the max payload is around 128T. Doing the maths from above, at a max ZFW of 288T there is around 79T of fuel available which gives a range of 6+ hours. The max reserve fuel to stay below MLW is ca. 14T.
This allows a 2 stop return from the Far East or one stop from (say) BKK to Europe depending on the season.
It is some years since I flew the pax. model but as I remember the MLW was considerably less and the MZFW the lower figure as above. Since the increase was, I believe, made by increasing the strength of the wing box and lower wing panels, I assume that the -BCF/-SF's MLW and ZFW is not increased by the freight conversion forever limiting it's payload to the stated maximum quoted above.
I don't know if any -Fs were certified at lower than the optional higher MTOW, it would seem unlikely anyone would have been foolish enough to limit it's potential by so doing. More likely that Boeing quotes the standard weight at the lower figure with an option to certify higher thus being able to charge $$$ for the paperwork exercise.
Last edited by Flightwatch; 27th Apr 2007 at 11:05. Reason: layout
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Well I'm current and qualified on the 744 as well
Weights Kilograms Freighter
Maximum Taxi Weight 395,986
Maximum Takeoff Weight 394,625
Maximum Landing Weight 302,092
Maximum Zero Fuel Weight 288,031
Nominal Empty weight 161,000
Weights Kilograms Passenger
Maximum Taxi Weight 397,800
Maximum Takeoff Weight 396,893
Maximum Landing Weight 285,763
Maximum Zero Fuel Weight 244,939
The BCF aircraft have had their max landing weight increased as well as their Max Zero Fuel Weight increased. There is no option for them to get increased payload via a MTOW reduction as there is on the 744F. The nominal empty weight of the 744BCF is 159,000.
Weights Kilograms Freighter
Maximum Taxi Weight 395,986
Maximum Takeoff Weight 394,625
Maximum Landing Weight 302,092
Maximum Zero Fuel Weight 288,031
Nominal Empty weight 161,000
Weights Kilograms Passenger
Maximum Taxi Weight 397,800
Maximum Takeoff Weight 396,893
Maximum Landing Weight 285,763
Maximum Zero Fuel Weight 244,939
The BCF aircraft have had their max landing weight increased as well as their Max Zero Fuel Weight increased. There is no option for them to get increased payload via a MTOW reduction as there is on the 744F. The nominal empty weight of the 744BCF is 159,000.
Interesting, particularly the comparison between the -SF and -BCF. How can a conversion achieving the same results produce aircraft with OEWs of 4.1T difference?
The difference between the -BCF and -400F on the routes I fly would be minimal as effectively the payload would be the same on a one stop Far East - Europe flight, often our flight plans are "reverse engineered" to give the max payload vs. the fuel required on any particular day with a reclearance thrown in. The result is usually around the nominal 117.6T a -BCF can carry albeit with 2.2T less fuel or payload.
However I can see that the operators of the heavier -SF might be upset, I don't pretend to know much about the economics and profit ratio of freight carrying but I guess that missing 4.1T could have a pretty dramatic effect on the success of a particular operation.
Also if interest is the difference between PS's -F and the ones I fly, a 2.2T difference in either payload or fuel/MTOW as referred to above is not inconsiderable during a year's operation. Is it to do with regulatory authorities or how much you pay Boeing?
It is easy to dismiss the nose cargo door but it can put the icing on the cake in terms of the money paid to carry out-sized cargo. Had a piece the other day around 3m x 15m, weighed next to nothing but centre loaded it filled a large portion of the main deck.
The difference between the -BCF and -400F on the routes I fly would be minimal as effectively the payload would be the same on a one stop Far East - Europe flight, often our flight plans are "reverse engineered" to give the max payload vs. the fuel required on any particular day with a reclearance thrown in. The result is usually around the nominal 117.6T a -BCF can carry albeit with 2.2T less fuel or payload.
However I can see that the operators of the heavier -SF might be upset, I don't pretend to know much about the economics and profit ratio of freight carrying but I guess that missing 4.1T could have a pretty dramatic effect on the success of a particular operation.
Also if interest is the difference between PS's -F and the ones I fly, a 2.2T difference in either payload or fuel/MTOW as referred to above is not inconsiderable during a year's operation. Is it to do with regulatory authorities or how much you pay Boeing?
It is easy to dismiss the nose cargo door but it can put the icing on the cake in terms of the money paid to carry out-sized cargo. Had a piece the other day around 3m x 15m, weighed next to nothing but centre loaded it filled a large portion of the main deck.
Last edited by Flightwatch; 28th Apr 2007 at 04:22. Reason: Geographical
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Converted B747-400's - Achieving the Performance Parameters?
Sincere thanks for the informative replies so far. I am familair with the various manufacturers web-sites which, occasionally, can be as suggested by 742 ".....simplistic, one page executive summaries" and do not always cover the variations, upgrades or downgrades to MTOW, MZFW etc. - and the there does appear to be a number of varying OEW's for the same model (depending which document you read!).
May I ask if anyone has any provisional weights for the 747-8F (MLW, MZFW, planned OEW etc.) as the Boeing site/Technical Information is rather sparse at this time? I understand that the MTOW is 439,985 kgs. with an approximate payload (structural or revenue) of circa 140,000.
Again, thanks for any useful updates.
May I ask if anyone has any provisional weights for the 747-8F (MLW, MZFW, planned OEW etc.) as the Boeing site/Technical Information is rather sparse at this time? I understand that the MTOW is 439,985 kgs. with an approximate payload (structural or revenue) of circa 140,000.
Again, thanks for any useful updates.
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How can a conversion achieving the same results produce aircraft with OEWs of 4.1T difference?
