The PZL SW-4 Puszczyk (en: tawny owl) is a Polish light single-engine multipurpose helicopter manufactured by PZL-Świdnik. Following a protracted development, the SW-4 entered service in 2002, the primary operator of the type has been the Polish Armed Forces. The SW-4 was further developed by PZL-Świdnik and corporate parent AgustaWestland into an optionally piloted vehicle, the SW-4 Solo. From 2016 onwards, the type has been marketed to civil operators as the AW009, while the SW-4 designation is used for the military market. Development Origins The design of the SW-4 helicopter originates from the 1960s, during which period it was decided against proceeding to production with the SW-4 due to demand for military helicopters from various nations within the Warsaw Pact. Around 1981, development work at PZL-Swidnik was started on a new four/five place light utility helicopter. The original design for the SW-4 called for it to be powered by a 300 kW (400 shp) PZL Rzeszow GTD350 turboshaft engine, as featured upon the prototype mockup. According to PZL-Swidnik, the early SW-4 could reach the rated top speed of about 240 km/h (130 kn) and a max range with auxiliary fuel tank about 900 km (485 nmi). Following the collapse of the Soviet Union and the subsequent European restructuring, predominantly those countries that had formerly been members of the Warsaw Pact, the emerging political climate had allowed PZL-Swidnik to redesign the SW-4 to make use of a new foreign-built powerplant, the Allison (now Rolls-Royce) Model 250 turboshaft engine, which was 13% more powerful while consuming 30% less fuel than the originally-intended GTD350 powerplant. Other changes were made to the design, which ultimately bore little resemblance to its earlier form. In 1995, the SW-4 project was formally re-launched and, in addition to the switch of power plant, the rotorcraft's design was substantially modified. Design alternations include the adoption of epoxy resin-based composite materials for the fuselage structure, further streamlining of the fuselage, and a revised tail and tail boom made primarily of aluminium. In December 1994, the project had proceeded to ground testing of a non-flying prototype. Subsequently, a pair of flight-capable prototypes were assembled to support the development program. The first prototype was planned to perform an initial flight in January 1995, however this was delayed due to vibration issues during engine runs. On 26 October 1996, the SW-4 was reported as having performing its first flight; an official first flight