At the heart of Boeing's 777X concept are three options for a new massive carbonfibre reinforced plastic (CFRP) wing.
The potential baseline wing has a 71.1m (233ft 5in) span and raked wingtip, and while the other two are 65m and 68.6m wings with blended winglets.
The 71.1m-long, 787-inspired CFRP wing would be the largest in Boeing's history and would grow the 777-300ER and 777-200LR's wing area by approximately 10%, allowing slower and quieter approaches.
Development of a carbonfibre wing requires a significantly different supply chain than the one Boeing has in place for today's 777s. Aluminium wing skins and spars are manufactured at the company's Auburn, Washington fabrication division and sent by truck to the Everett final assembly line for build-up.
Scott Fancher, former 787 chief and newly appointed 777 vice-president and general manager, is tasked with aligning "the 777 production system with the next generation 777".
After the painful supply chain woes of the 787, Commercial Airplanes chief executive Jim Albaugh has suggested that Boeing should "never outsource" wing design and manufacturing to protect its intellectual property.
Such an investment by Boeing would require significant autoclave and facility investment to match the 100 777s per year that the airframer will build in 2013. The wing's span would likely make it too large to be flown to final assembly by the modified 747-400 Dreamlifter large cargo freighter designed for the 787 programme.
The 71.1m wing would also push the 777 from ICAO Code E airport classification to Code F standards, the same category occupied by the 747-8 and A380. Under study is a revival of the original 777-200 wing-fold concept, which would have tilted upward a 6.9m (22ft 6in) portion of the wing that included the outer two leading edge slats and outboard aileron to accommodate McDonnell Douglas DC-10-sized gates.
Boeing's current concept scales back the weight and complexity of the design by folding only the raked wingtip, which is understood to be a 3.4m (11ft) portion of the wing, and does not house any wing control surfaces.
In short, Boeing would maintain Code E standards on the ramp and taxiway, up to 65m (213ft 4in), in line with today's 777-300ER, and shift to a Code F classification upon entering the runway.