Cargolux's refusal to accept delivery of the first Boeing 747-8F, ostensibly due to a performance shortfall, is linked to an ongoing dispute between Qatar Airways, a 35% shareholder of the cargo carrier, and Boeing over compensation for delays to Qatar's 787s.
Speaking on condition of anonymity at the ISTAT conference in Barcelona, one source familiar with the situation indicated that Cargolux and Boeing had previously agreed a framework for compensation.
But after Qatar acquired its stake in Cargolux on 9 September, a new dynamic entered the picture - compensation for delays to the 787.
According to multiple sources at ISTAT, Qatar's chief executive Akbar Al-Baker views the compensation for Cargolux as setting a benchmark for the sum due for the delays to Qatar's 787s.
Qatar Airways was unable to comment on the situation.
The performance shortfalls of the 747-8F have been known to customers for at least a year as production proceeded.
However, according to sources, another customer remains locked in negotiations with the airframer over deliveries for its 747-8Fs.
The customer does not want the early freighters it is contracted for, instead preferring to skip to a later group that have line-fit production improvements rather than reworking the aircraft it receives.
These negotiations continue and may come to fruition as early as this week, said a source familiar with the situation.
Boeing said that although the -8F is over its original specification weight, this is due to the extensive redesign of the aircraft that has taken place. It said: "After we set our original specification, we completely redesigned the wing, which is significantly heavier, but more than makes up for that in increased aerodynamic efficiency and lower fuel burn.
"As with all our airplanes, Boeing will continue to seek further improvements in weight throughout the life of the programme."
It said that while the initial freighter deliveries "will be somewhat short of initial specifications for fuel burn", it and engine supplier GE are working on further performance improvements.
"Even at entry into service, the 747-8 will be a great airplane for our customers, and give them unparalleled efficiency and low cost."