The first Northrop Grumman-built centre fuselage for the F-35B short take-off and vertical landing (STOVL) version is due to arrive at Lockheed Martin's Fort Worth final assembly line on 15 January. The unit, weighing 1,770kg (3,900lb) and dubbed BF-1, is the first "optimised" centre fuselage to be delivered after the redesign that cut the F-35's weight by 1,360kg. Northrop Grumman, which has begun assembling the first fuselage section for CF-1, the first F-35C carrier version (CV) for the US Navy, has 10 airframes "in flow" for the system design and development phase at its Palmdale, California site.

SDD will eventually encompass 14 production-representative flight-test aircraft - five conventional take-off and landing (CTOL), four STOVL and four CV - that are planned to fly by mid-2009. Six more airframes are also being manufactured for static and fatigue tests. Under the latest low-rate initial production plans, Northrop Grumman plans to deliver a further six units to Lockheed Martin in 2007 where 11 aircraft are planned for final assembly through the year. This includes the first weight-optimised CTOL airframe, AF-1, due for delivery to the Texas production line around September 2007.

"We're moving towards an integrated assembly line which will eventually reach a rate of one centre fuselage a day," says Northrop Grumman F-35 deputy programme manager Randy Secor. Full rate could be reached over the 2012 to 2014 period depending on how funding matches up to current production plans, he adds. These call for fuselage section output to rise to 14 a month by 2014 and up to 22 a month by 2016. Although both milestones for BF-1 and CF-1 were originally planned for November, Secor says the programme remains ahead of schedule. The delay to BF-1 was caused by "36 changes in wire harnessing" which were introduced late on in the design after lessons learned from development of AA-1, the first flying F-35.

Source: Flight International