By James Drew

The Lockheed Martin F-35 Joint Strike Fighter programme’s concurrency cost has ticked up by $40 million since last year’s estimate by the Pentagon to $1.69 billion, according to a report recently sent to US lawmakers.

That is how much the US Department of Defense expects it will cost to retrofit hundreds of early production F-35s with fixes to problems discovered during development and testing.

According to the March report, obtained by Flightglobal, the 2% increase over last April’s estimate accounts for new flaws discovered in the developmental aircraft, plus increases in the expected cost of fixing other problems that were already known to developers. Of the sum, $1.19 billion is for known issues and $500 million is for forecast issues.

“Overall, the F-35 concurrency cost estimate remains stable,” the document states, while noting that the figure is lower than estimates in September 2012 ($2.57 billion) and May 2013 ($1.75 billion).

The report looked at American F-35s only, and the total amount accounts for a 50-50 concurrency cost sharing clause with prime contractor Lockheed Martin in low-rate initial production contracts five to eight.

F-35 joint program office spokesman Joe DellaVedova says the programme has a team dedicated to “deep diving” into concurrency costs, which has improved the way those costs are monitored and managed.

DellaVedova told Flightglobal the F-35 team has been working to reduce the time between finding a problem, engineering a solution and cutting the fix into the production line. “If we can speed up that time frame, it saves a large amount of money,” he says.

The programme has also tried to limit the impact of last year’s F135 engine failure that temporarily grounded the fleet. F-35 engine manufacturer Pratt & Whitney has agreed to shoulder the bulk of the cost associated with that fix, including modification to engines already in the field plus the cost of incorporating the design changes into the production line. Meanwhile, the JPO will pay for design activities.

“Concurrency is a temporal issue that will pass, and much of the discovery has already happened,” DellaVedova said.

The report looked at American F-35s only, and the total amount accounts for a concurrency cost-sharing clause with prime contractor Lockheed Martin in production contracts five to eight.

Lockheed has already delivered 140 aircraft with about 40% of the flight testing still to be done, and programme officials expect to discover more issues as testing continues.

“This is not the same programme it was five years ago,” F-35 executive officer Lt Gen Christopher Bogdan said at a Norwegian-American defense conference in Washington last month. “We only have two years of development left and we are seeing the amount of discovery in the test programme come down significantly.

“We're also seeing the cost of that concurrency or overlap come down dramatically over the last few years, and we feel by about 2017, 2018 we will be out of this rut in which we are building airplanes that now have to be retrofitted because of a new discovery.”

The F-35 programme is burdened with one of the largest overlaps in production and testing ever seen in a military acquisition because of the decision to scale up production several years ahead of full flight testing.

The Government Accountability Office’s Michael Sullivan said at congressional hearing last month that unanticipated engine and bulkhead failures are the most recent examples of the F-35’s “ongoing struggle with concurrency and the cost and schedule risks it brings”.

The congressional watchdog noted in an April report that the DOD intends to purchase 340 F-35 aircraft by the end of 2017 when the 14-year-old development phase is scheduled to be complete.