In 1986, the USAF established the ADF (Air Defence Fighter) program in the course of which more than 270 F-16A/B Block 15 aircraft were upgraded to Block OCU aircraft and modified for the ANG departments. These planes had improved avionics and could be used with semi-active AIM-7 Sparrow radar-guided air-to-air missiles. The Italian Military Aeronautics Division leased 45 thousand hours of flight-time, between 2003 and 2010, for thirty F-16 Block 15 ADF aircraft upgraded to standard "Falcon Up" aircraft, and four F-16 Block 10 aircraft of converted operation. The work began on 28 June 2003, with the first F-16 landing at the Sicilian base, and on 22 May 2008 the aircraft of the 37th formation cut down 30,000 hours of flight-time.