Building on its 777-300ER, Boeing is evaluating its next moves in the 300 to 415-seat market with its conceptual 777-8X/9X, powered by a smaller GE90-derived engine, composite wing, a possible fuselage stretch and higher economy seating capacity.

This marks what is likely to become the second major incremental evolution of the 777 family, 15% better than today's aircraft.

Boeing's available options that are now coming into focus look to grow the 213ft metallic wingspan of the long-range twin to as much as 71.3m (234ft) with a carbonfibre design, and 30.5m (10ft) wider than the 747-8. Initial estimates being evaluated by Boeing point to a lower maximum takeoff weight of around 342t (753,000lbs) for the 777-9X, which would anchor the family and preserve the payload range capability of today's aircraft.

The move would transform significant portions of the 777's manufacturing footprint with the introduction of composite fabrication to the wing's primary structure. The 777 programme has seen such transformations before, transitioning to a moving U-shaped final assembly line between 2006 and 2010 continually refining and consolidating the manufacturing process.

Without confirming details, Boeing said in response to queries that the 777 family "will benefit from years of additional refinements based on customer input and the application of new 787 technologies before the [Airbus] A350-1000 is scheduled to enter service".

"We are confident that, when the market demands it, we can develop and deliver a superior airplane that provides unparalleled value to our customers. We have been working hard on developing options and we feel very comfortable with where we are in that process," it said.

To power the new jet, Boeing and General Electric look to be investigating a scaled down GE90, part of its GE9X study, by evaluating a 325cm (128in) diameter fan with a lower 99,500lb thrust, a reduction of 15,500lbs from the 343cm (135in) GE90-115B that powers the 777-300ER today. The engine would draw on technology introduced on the GEnx platforms, as well as implement ceramic matrix composites for the turbine section.

With a late-decade service entry, the larger wing and its increased lift to drag ratio, coupled with the a 10% improvement in specific fuel consumption for the GE9X engine, along with material improvements across the aircraft would aim to improve fuel burn by 15% on a per seat basis.

Boeing is currently studying the entry into service timing of its widebody models to follow the 787-9 in late 2013. In response to the A350-900, Boeing is evaluating the pacing of a larger 787-10X stretch and the 777-8X/9X.

As part of the studies, Boeing is examining optimising the fuselage around the new larger wing and looking at both a fuselage stretch and a shrink of the 777-300ER. One conceptualisation of the -9X would be an additional stretch to the 777-300ER, while the -8X would be a shrink of the 365-seat jet, The 777-8X and -9X would allow Boeing to span the products between the proposed 330-seat 787-10X and 467-seat 747-8.

Further, as part of the study Boeing would offer a new 787-style interior, with LED lighting and larger overhead bins to the type, as it has done with its 747-8 and 737 families. In the cockpit, Boeing is looking at flight deck and avionics updates for future air traffic management systems, as well as systems architecture upgrades that would bring parts of the 787's ARINC 629 standard and increased electrical usage to the 777.

Source: Air Transport Intelligence news