Boeing is expecting a formal announcement "very soon" from the International Civil Aviation Organisation (ICAO) regarding the wake separation requirements for both freighter and passenger models of the 747-8, said 747 vice president of engineering, Todd Zarfos.

Zarfos said all the data for the vortex evaluations have been submitted to ICAO and the results were "in line with what we expected" for the aircraft's 68.5m (224ft 7in) wingspan.

During its flight trials, Boeing compared the wake of a 747-400 to that of the -8F, seeking to carry over the 7.4km (4nm) separation requirement that currently applies to the 747-400.

With its now-awarded US Federal Aviation Administration and European Aviation Safety Agency certifications, Boeing expects to deliver the first 747-8F to launch customer Cargolux in early September.

Source: Air Transport Intelligence news