Paul Lewis/SEATTLE

Boeing has reaffirmed its commitment to launching the planned 777-200X/300X derivatives and is undertaking a fresh examination of a range of payload/range performance enhancements to the design.

"The programme is still proceeding and there are some opportunities to make improvements to the 777-200X/300X that we are now entertaining. There are lot of things we could still do to this aircraft and we are taking a hard look at these things," says product marketing director, Joe Ozimek.

Boeing is considering a "modest" increase in the aircraft's maximum take-off weight (MTOW), while striving to improve its field performance. To achieve this, the company is looking at aerodynamic lift refinements and the potential for increased engine thrust.

Boeing is taking a further look at lift refinements to cut the aircraft's projected 3,660m (12,000ft) MTOW field length by 300m.

The proposed ultra long haul 777-200X and stretched -300X are now being offered to airlines with MTOWs of 333,700kg and 324,600kg, respectively. Boeing is looking at the possibility of raising this by another 4,500-6,800kg for better payload/range performance, but to achieve this it needs an 1% to 2% increase in available thrust. "This depends on testing of the engines, clearly there is a potential to have more thrust," says Ozimek.

Rolls-Royce is scheduled to conduct its first test run in December of the growth Trent 8104 engine, now being offered for the 777-200X/300X flat rated at 454kN (102,000lb) thrust. Pratt & Whitney has also signed a memorandum with Boeing to offer a similar size growth development of its PW4000 engine series.

The additional MTOW margin would enable Boeing to offer airlines wanting to operate on marginal revenue routes increased passenger and cargo capacity. The 777-200X is being marketed with a range of 16,100km (8,700nm) in a 300-seat configuration.

Following Singapore Airlines' decision to opt for the Airbus A340-500, Boeing has moved the 777-200X's planned entry into service date back to mid-2002.

Source: Flight International