The US Air Force's top official confirms that entry-into-service date for the Lockheed Martin F-35A variant will be delayed again due to the programme's second major restructuring in less than a year.

The changes first announced on 6 January that extend the system development and demonstration phase to early 2015 "implies" a new delay for the initial operational capability (IOC) milestone, secretary of the Air Force Michael Donley told reporters on 12 January.

Donley did not specify the extent of the new delay for the F-35A conventional takeoff (CTOL) variant. The A-model has drawn a USAF commitment to buy 1,763 aircraft despite average unit costs rising from $50 million to $92 million since 2001.

The F-35 joint programme office declined to elaborate on the meaning of Donley's implication, but noted that "all three services will reassess their planned IOCs" because of the restructuring.

The revised schedule adds $4.6 billion to the development phase - now estimated to cost nearly $51 billion over 15 years -- to add more testing and to correct cost estimates that were too low.

The new delay for the F-35A's IOC milestone means the USAF will have to commit more resources to sustain Lockheed F-16s.

"It's not longer if" we will extend the service life of F-16s, Donley said. "It is more of a 'how much, and when and what kind' [question] rather than if."

Details of the new service life extension programme for F-16s will likely be revealed with the USAF submits the Fiscal 2012 budget request to Congress in early February.

Source: Flight International