 After becoming an officer at an official exam at Uppland Air Force Wing (F 16), Nilsson learned to fly the Saab 37 Viggen at Hälsinge Air Force Wing (F 15) in Söderhamn, before transferring in 1979 to Blekinge Air Force Wing (F 17) near Ronneby.There he served as a Tactical Reconnaissance Pilot and flew Saab 37 Viggen as a lieutenant.Nilsson was stationed in Blekinge when the Soviet submarine "U 137" ran aground on 27 October 1981 southeast of Karlskrona.