I was looking at this 747 Freighter brochure from the 2005 Paris Air Show and it struck my attention that with the higher MZFW option, the 747-400ERF has slightly lower structural payload than the 747-400F, 272,600 lb versus 273,300 lb.
Why is this the case?
Other then that, the specifications of the 747-400F and the 747-400ERF with the higher MZFW option appear to be identical. The range for both is listed as 2,815 nm, the MZFW for both is listed as 635,000 lb and the MTOW for both is listed as 811,000 lb.
Does this mean the advantage of the 747-400ERF over the 747-400F is pretty much only if the higher MZFW option is not selected? Makes you wonder why it is offered on the 747-400ERF to begin with.
Any feedback would be greatly appreciated.