The main market for the aircraft is corporate transport and regional airliner operators. The PC-12 is the best-selling pressurized single-engine turbine-powered aircraft in the world and has been for several consecutive years, with 1,700 deliveries as of October 2019. In October 1989, Pilatus announced the development of the PC-12 at the annual convention of the National Business Aviation Association (NBAA). Prior to the 1989 announcement, the PC-12 project had been worked on for some time under high levels of secrecy; by the time of the announcement, assembly of the first prototype had already commenced. Pilatus believed that the PC-12 would fit a new market not served by existing aircraft and that the type would be the first single-engine aircraft capable of a large volume at high speed across long distances. The two prototypes were completed on 1 May 1991, with the first flight taking place on 31 May 1991. Swiss certification of the type had been originally planned for mid-1991; however, a redesign of the wings (increase of wingspan and addition of winglets to ensure performance guarantees were met) delayed progress. On 30 March 1994, the Swiss Federal Office of Civil Aviation issued the type certificate for the PC-12; Federal Aviation Administration approval in the U.S. followed on 15 July 1994. Australian Users. Royal Flying Doctor Service - operates 31 PC-12s for EMS/medical transport duties. Western Australia Police - operates two PC-12s for staff transport, search and rescue and disaster relief. Northern Territory Police For more details of the development, design and variants, click here.