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

[Flightwatch]

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.