The 747-8 freighter contract dispute has made delivery this week of the new jumbo to Cargolux "highly unlikely" as the parties continue to negotiate, said industry sources.
Cargolux is said to have cancelled a planned 23 September event with the 747-8F in Luxembourg. Cargolux was unreachable for comment.
Boeing declined to comment on delivery timing for this week, and stated: "We continue to work with Cargolux to find a time to deliver its airplanes."
Cargolux informed Boeing on 16 September that it had "rejected" the first two 747-8 freighters for delivery over a "contractual issue", halting the planned 19 and 21 September 747-8F deliveries.
Ongoing negotiations between Boeing, General Electric, Cargolux and 35% stakeholder Qatar Airways centre on the freighter's performance targets, but at issue appears to also be Qatar Airways standing order for its GEnx-powered 787s, according to Flightglobal sources at the ISTAT conference in Barcelona.
Along with the 13 747-8Fs Cargolux has on order, Qatar Airways holds orders for 30 787s and two 747-8s for VIP Government use, CEO Akbar Al Baker confirmed at June's Paris air show.
Boeing acknowledged the gap in the 747's performance, calling the first airplanes "somewhat short of initial specifications for fuel burn".
However, Boeing and GE are still finalising the configuration of the 747-8's GEnx-2B performance improvement package (PIP) expected in 2013, while the 787s are set to receive dual PIP1 and PIP2 improvements for the GEnx-1Bs later in 2011 and 2012, respectively.
Industry sources indicate there have been no major changes to customer expectations of the aircraft's performance over the past year.
Along with the 747-8 PIP, "coupled with a number of aerodynamic improvements we have identified for implementation, we are confident that the airplanes we are selling today will meet our customer specifications", said Boeing.
Any performance improvement package developed by GE would be available for retrofit, though such a backward implementation would not come for five to seven years when the engine undergoes its first overhaul.
Boeing also "completely redesigned" the 747-8's wing, which made it heavier. The airframer stressed the added weight "more than makes up for that in increased aerodynamic efficiency and lower fuel burn". However, Boeing added that while conducting the flight loads survey during flight test it discovered further areas of weight saving, but also increased the aircraft's maximum taxi weight, maximum takeoff weight, maximum landing weight and maximum zero fuel weight.
"Our flight loads survey testing presented us opportunities to further enhance the airplane's performance through further weight savings as well as to improve our payload range capability," said Boeing.