US Secretary of Defense Leon Panetta has lifted a probation order that had threatened the Lockheed Martin F-35B short take-off and vertical landing (STOVL) variant with the possibility of instant termination for more than one year.

By granting the reprieve one year early, Panetta recognized the progress the F-35B made last year in flight tests after resolving five major technical problems that sidelined the variant for nearly all of 2010.

"We certainly are making progress," said Steve O'Bryan, Lockheed vice president of programme integration and business development.

The F-35B completed several major milestones during the year, including first shipboard vertical landing. The F-35B test flight also exceeded the number of planned flights and test points during the year, a strong reversal from its performance in 2010.

At the same time, the F-35B encountered several new technical problems in 2011, although none that disrupted the test schedule as severely as the year before.

Vice Admiral David Venlet, the F-35 programme executive officer, also has complained about the cost of retrofitting design changes on the growing number for early production aircraft.

Gen James Amos, commandant of the Marine Corps, welcomed Panetta's decision to lift the probation order, but acknowledged the F-35B's status remains a daily priority.

"I will continue to closely monitor the jet's progress on a daily basis, as I have over the past 13 months," Amos said.

The one-year probation term may still have a long-term effect on the F-35B production programme. As part of the terms of probation, the Department of Defense slashed the F-35B production rate to six aircraft per year through 2014.

It was not immediately clear if the DOD would restore some or all of the F-35B's production ramp-up during the low-rate initial production phase. The DOD plans to release its next six-year spending plan, including the Fiscal 2013 budget request, to Congress in early February.

Source: Flight International