Defence and aerospace company Boeing will convert retired U.S. Air Force’s F-16 jet fighters into unmanned target drones under terms of a $49.7 million contract announced last week.

Officials of the Air Force Life Cycle Management Centre at Eglin Air Force Base awarded a contract to Boeing to handle the conversion of about 15 Block 25 and Block 30 F-16 fighters into unmanned QF-16 full-scale aerial targets (FSATs).

The Air Force had used converted jet fighters as target drones for decades, beginning in the 1960s when the Air Force converted 24 F-104 Starfighter jets into target drones.

Other U.S. jet fighters, including the F-100, F-102, F-106, and F-4, have become target drones. Air Force experts use converted jet fighters as target drones to test sophisticated missiles and electronic warfare systems.

Although some of these retired jet fighter target drones are destroyed during weapons tests, often the drones rely on onboard sensors to calculate the point of missile detonations to record “kills” without destroying the target aircraft.

The QF-16 target drones are replacing the Air Force’s fleet of QF-4 target drones, converted from McDonnell Douglas F-4 Phantom jet fighters, which were phased out of active service in the 1980s.

Air Force leaders are expected to buy a total of 210 QF-16 through 2022. The first manned QF-16 flight was in May 2012, and the plane’s first unmanned flight was in September 2013. Boeing will complete the work by April 2025.