Delays and cost overruns for the Lockheed Martin F-35 have not changed the US Air Force's plans to deactivate about 250 fighters later this year, says its chief of staff, Gen Norton Schwartz.

The USAF, however, has begun destructive tests on Boeing F-15s and Lockheed F-16s to prove the viability for a potential service life extension programme, says Schwartz.

"At 10-15% of the cost [of a new fighter] you could perform a service life extension programme," Schwartz says, "which would get us close to where we need to be in, we think, a more affordable way."

Schwartz rejected buying the latest "fourth-generation-plus" versions of the F-15 and F-16 despite a new two-year slip and nearly 90% projected cost overrun for the F-35. "To be sure, we do not think it prudent to utilise precious procurement dollars for anything but fifth-generation aircraft." But Schwartz added an important caveat, that the USAF still has not determined whether the service life extension programme would be technically or financially viable.

The USAF has terminated Lockheed F-22 production with 186 aircraft in inventory after 2011, leaving only plans to acquire 1,763 F-35s over the next 30 years to modernise its fighter fleet. Meanwhile, the 2010 Quadrennial Defense Review set the tactical aircraft requirement at about 2,000 fighters.

During the F-35's projected lifetime in production, however, the USAF faces a growing fighter inventory gap made even more complicated by Lockheed's cost and schedule problems.

In 2009 the Government Accountability Office (GAO) reported alarming trends. Twelve Air National Guard units today patrol US airspace with F-16s scheduled for retirement by 2020. As of late 2008, only one of the 12 units was scheduled to receive F-35s by 2020 to continue flying the mission.

The increasing gap in the fighter inventory prompted a US lawmaker to predict the air force's dependence on the F-35 will be a "monumental mistake".

"When these F-16s and F-15s are no longer able to fly and the F-35s still has problems because somebody hasn't figured it out, you're going to have air guard units that are not going to have planes," says Representative Frank LoBiondo, who represents a district that includes an F-16 base, during a 24 March hearing.

Source: Flight International