The U.S. Air Force plans to upgrade more than 300 Lockheed Martin F-16s and potentially additional Boeing F-15s to fill the gap caused by delays to the Lockheed Martin F-35 Joint Strike Fighter program.

The service shortly will announce plans to extend the service life and upgrade the avionics on 300-350 late-model Block 40 and 50 F-16s, Lt. Gen. Herbert Carlisle, deputy chief of staff for operations, plans and requirements, told Congress last week.

The structural and avionics upgrades are projected to cost $9.4 million per aircraft, he said. Extending airframe life to 10,000 hr. from 8,000 will add about eight years of service life and extend the capability of the F-16 fleet to 2030.

The service life extension is required because of delays in developing and fielding the F-35. Initial operational capability (IOC) of the Air Force’s F-35A variant was planned for 2018 but has slipped by about two years, Carlisle said.

The new IOC date will be determined once an updated F-35 integrated master schedule is completed. This is expected “fairly shortly,” Carlisle said. Built on a technical baseline review that extended JSF development by two years, the new schedule will detail how the F-35 will be fielded to replace F-16s and other aircraft in the active Air Force, Air National Guard and Reserve.

Although the Air Force has enough Block 40 and 50 F-16s to upgrade as many as 600 aircraft to cover any fighter shortfall should there be further F-35 delays, “we do not believe we will have to go there,” Carlisle said.

The Air Force is already upgrading 176 F-15C/Ds to operate through at least 2025 and fill the gap left by termination of Lockheed Martin F-22 production after 187 aircraft. “We may extend ‘long-term’ status to the entire 250-aircraft inventory based on requirements of the future force structure,” Carlisle testified.

The F-15s are receiving active, electronically scanned array radars, and both Northrop Grumman and Raytheon have responded to a prior Air Force requests for information to install similar high-performance radars in the F-16.