Converted B747-400's - Achieving the Performance Parameters?

[Flightwatch]

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.