Weight concerns and changes to construction methods threaten production efficiency

Growing partnership demands and aircraft weight issues appear to be slowly chipping away at Lockheed Martin's ambitions for a super-efficient final assembly line for the F-35 Joint Strike Fighter.

The UK's desire for a local final assembly and checkout (FACO) centre may cost the programme an extra £77 million ($127 million) alone, says a UK Ministry of Defence-sponsored report.

In another revelation, the Rand report says that Lockheed Martin now plans to "abandon" the quick-mate joints that were a hallmark of the aircraft's highly touted lean assembly technique.

Lockheed Martin's original plan called for mating each major section of the aircraft using machined planes with pre-drilled holes that are simply fastened together. Combined with a laser tracker, the quick-mate joints were expected to reduce a 10-day assembly process to a few factory shifts.

"The net effect of [abandoning the process] will probably be an increase in work content - and schedule and costs - to the final assembly stage," notes the Rand Europe report, titled Assembling and Supporting the Joint Strike Fighter in the UK: Issues and Costs.

But Lockheed Martin disagrees with the word "abandon", describing the company's action "more as scaling back".

JSF's quick-mate joints have been replaced by an "integrated joint", a move that trims the aircraft weight by 320-360kg (700-800lb), says Lockheed Martin. The original joints were dropped soon after a critical design review earlier this year showed the aircraft exceeded its weight target by 30%. Kent concedes the trade-off is a longer assembly period, but the cost increase is projected to be a "fraction of a percentage point".

The Rand report estimates that opening a separate FACO-only facility will raise the UK's final assembly bill by nearly £47 million and the US government's cost - factoring in reduced efficiencies - by another £30 million.

The US Navy reduced its order by one-third earlier this year, slightly increasing per unit aircraft costs across the programme. "The UK can expect to face increased costs from this decision," says the report.

Rand analysis suggests the UK would be wise to pair the FACO facility with a JSF maintenance and support centre. BAE Systems, Marshall Aerospace and the Defence Aviation Repair Agency are listed as the most likely candidates for basing the FACO facility.

If approved, a UK-based assembly line must be in place by 2009 with construction beginning two years earlier.

That means the UK government has only three years to secure the needed technology transfer agreements. "The process is complex, and the complexity makes the timing unpredictable," says the report.

Source: Flight International