Assembly of the first A350 XWB's 32-metre-long carbon fibre wings has begun at Airbus' recently-opened North Factory in Broughton, UK. Pre-assembly of ribs, upper and lower covers and fixed leading and trailing edges already has taken place. These components will be moved into the main assembly jigs for full wing box integration. Most of the A350 XWB wing is made of lightweight carbon composites, including the upper and lower wing covers, stringers, front and rear spars. The advanced structural design and superior wing aerodynamics are significant contributors to the aircraft's 25 per cent fuel-saving performance.