The Shenyang J-6 is the Chinese-built version of the Soviet MiG-19 'Farmer' fighter aircraft, the world's first mass-produced supersonic aircraft. The J-6 was considered "disposable" and was intended to be operated for only 100 flight hours (or approximately 100 sorties) before being overhauled. The Pakistan Air Force was often able to extend this to 130 hours with diligent maintenance. The PLA, the Chinese Army, stocks more than 4,500 old decommissioned J-6 fighter jets, mostly active in the 1970s. These UAVs are deployed for more operational purposes at Longtian Military Air Base, the closest Chinese air base to Taiwan (less than 180 miles from Taipei) At Longtian airbase, converted J-6s are used as decoys to deceive and overwhelm enemy air defenses. Using them over Taiwan could deplete enemy missile defense resources and expose anti-air positions.