A380, 747-8F Demand And Backlogs Are Shrinking
By Jens Flottau, Guy Norris
Source: Aviation Week & Space Technology
Part of Boeing's optimism is built on the raft of upgrades and improvements that will be rolled into the 747 by 2014. The manufacturer has committed to reducing the operating empty weight by 6,500 lb. but is looking for more. “We're on our way to a 10,000-lb. weight reduction,” says 747-8 Chief Project Engineer Bruce Dickinson. “We've taken the lower-hanging fruit for the first 5,000 lb.,” he adds. Some elements such as a lighter thrust reverser will be retrofittable, though Dickinson says other weight-saving structural improvements, such as modified washers and sealants, cannot be easily changed after assembly.
Additional aerodynamic, propulsion and systems improvements are also in the pipeline for introduction in 2014. Chief among these will be the General Electric GEnx-2B performance improvement package, which is designed to bring a 1.6% improvement in fuel burn for introduction into service by the end of 2013 (see page 36). This could rise even more, says Dickinson. Other improvements are in hand for the flight management computer (FMC) to incorporate features such as required navigation performance and a “quiet climb” function. The FMC 3.0 load is scheduled for the end of 2013.
A big-ticket upgrade remains the activation of the 747-8 passenger model's 3,300-gal. tailplane fuel tank. This was disabled before the first aircraft entered service after analysis indicated that, under certain fuel load circumstances, the tail tank could induce flutter. The first parts are now being built for the modified system, which will be introduced with other improvements in early 2014.
Reactivation of the tail fuel tank is a key enabler to improving the aircraft's performance, says Lufthansa 747-8 Chief Pilot Elmar Boje. Although the extra fuel provides additional range, Lufthansa is also keen to use the increased aft weight to assist in trimming the 747-8 to lower cruise drag. The 747-8's fuselage extension “tends to be nose-heavy so we might gain performance,” Boje says. Lufthansa also plans to ask Boeing to study minor software changes to the fuel transfer system that would lengthen the amount of time the fuel is in the aft tank.
All the improvements are due to be flight tested next year. Lufthansa is due to take another five 747-8s in 2013, and 10 more, all with the lighter structure and improved systems and engines, are due for delivery by the end of 2015.