Boeing plans to invite a group of up to 12 key airlines by the end of May to help focus its plans for a family of high-speed, ultra-long haul subsonic airliners seating 100-300 passengers which could be in service as early as 2007.

The study airliner family, as yet undesignated, is the first spin-off from Boeing's 'Project 20XX' and was first revealed in January (Flight International, 23-29 January). This name covers a swathe of technology development efforts aimed at providing a broad platform of advanced systems, manufacturing, design processes and aerodynamic breakthroughs on which to launch a new family of aircraft.

The proposed aircraft will fly at between Mach 0.95 and 0.98, at altitudes in excess of 45,000ft (13,725m) with a maximum range potential beyond that of the 777-200LR and -300ER. While overall capacity is, as yet, undetermined, says Boeing Commercial Airplanes vice president business strategy and development Mike Bair, the aircraft "is not going to be 747-sized. We just don't know what size it will end up." Boeing plans to "move relatively quickly", says Bair, adding that it will "probably be nine to 12 months before we get in a position to solidify particulars".

Bair says the main focus is on the 100- to 300-seat range, implying the potential birth of a mid-range capacity family to replace 757s and 767s. With the emphasis on high speed, high altitude and very long range characteristics, Boeing's plan appears to be aimed at developing the ultimate market fragmenter.

"We have the opportunity to start a new family of aircraft," says Bair. The projected aircraft will be "15% to 20% faster" than current aircraft, meaning shorter flight times of more than one hour on US transcontinental routes, around two hours less on typical transatlantic routes, and as much as a three hour saving on some Pacific sectors.

The unconventional configuration, on which Boeing is shortly preparing to begin transonic wind tunnel tests, is also "really quiet", he adds. This suggests a move away from Boeing's standard wing-mounted, pylon hung engine location, to either tail mounted or embedded. Thrust ranges of between 40,000lb and 80,000lb (178 and 356kN) are being considered, and variants of current engines will be used, says Bair.

New technology on offer to the airlines as part of the package is expected to include active flight controls, a high-aspect ratio supercritical wing, integrated nacelles and extensive use of composites in the primary structure.

Bair says that, assuming an outline configuration can be determined by the first quarter of 2002, full-scale development could begin either in 2003 or 2004.

Timing will also depend on "whether it's a normal aircraft, or it can be more". Either way, development time to certification is expected to be considerably shorter than any previous Boeing aircraft, says Bair who adds it will "probably" be less than that of the 777.

Source: Flight International