Guy Norris and Paul Lewis/SEATTLE

BOEING IS targeting September for a decision on development of either the 777-100X "shrink" or higher gross weight -200X derivative as its new ultra-long range passenger aircraft.

A continuing product development study of the two new proposed 777 family members is due to be reviewed in September, after which Boeing wants to move into detailed design work. Full-scale development will take between three and five years, depending on the version launched.

The US manufacturer, is discussing two different ultra-long range 777 configurations, with potential US and Asian operators and is not ruling out the development of both. "They could push us in both directions," says product marketing regional director, Daniel Olason.

Boeing had originally been focusing on the 15,725km (8,500nm)-range 777-100X to counter the ultra-long haul Airbus A340-8000. The 250-seat aircraft would have a 6.4m shorter fuselage and a maximum take-off weight (MTOW) of just under 300t.

The launch by Airbus in late 1995 of the ten-frame shrink A330-200 has prompted Boeing to consider development of the larger 777-200X. The aircraft retains the 777-200's standard 63.7m-long fuselage, but has an increased 313t MTOW and 15,000km maximum range.

The -200X is attracting increasing interest from several carriers as it would offer a 8-9% lower seat per kilometre cost than that of the smaller capacity -100X, claims Boeing. The aircraft would not be available until 2001 however, two years after the -100X's projected entry into service.

Additional time is needed to engineer and certificate the 777-200X to take more powerful 425-435kN (95,000-98,000lb)-thrust engines, initially being developed for the stretched 368-seat 777-300.

The new 777-300 growth engines will not enter service until September 1998, too late for a higher gross weight -200X version in 1999, says Boeing. The -100X instead would be fitted with less powerful 400kN-thrust engines, the first of which is due to enter commercial service early in 1997 on the 777-200IGW.

Source: Flight International