PZL M28 Skytruck
The PZL M28 Skytruck is a Polish STOL light cargo and passenger plane, produced by PZL Mielec, as a development of licence-built Antonov An-28s. Early licence-built planes were designated PZL An-28. The maritime patrol and reconnaissance variants are named PZL M28B Bryza ("sea breeze"). Development. The Antonov An-28 was the winner of a competition against the Beriev Be-30 for a new light passenger and utility transport for Aeroflot's short haul routes, conceived to replace the highly successful An-2 biplane. The An-28 is derived from the earlier An-14. Commonalities with the An-14 include a high  wing layout, twin fins and rudders, but it differs in having a reworked and longer fuselage, with turboprop engines. The original powerplant was the TVD-850, but production versions are powered by the more powerful TVD-10B, with three-blade propellers. The An-28 made its first flight as the An-14M in September 1969 in USSR. A subsequent preproduction aircraft first flew in April 1975. Production of the An-28 was then transferred to Poland's PZL Mielec in 1978, although it was not until 22 July 1984 that the first Polish-built production aircraft flew. The An-28's Soviet type certificate was  awarded in April 1986. PZL Mielec has become the sole source for production An-28s. The basic variant, not differing from the Soviet one, was designated PZL An-28 and was powered with PZL-10S (licence-built TVD-10B) engines. They were built mostly for the USSR, until it broke up. The plane was next developed by the PZL Mielec into a westernised version powered by 820 kW (1100shp) Pratt & Whitney PT6A-65B turboprops with five-blade Hartzell propellers, plus some western (BendixKing) avionics (a distinguishing feature are exhaust pipes, sticking out on sides of engine nacelles). Designated the PZL M28 Skytruck, the first flight  was on 24 July 1993 and it is in limited production, mostly for export (39 produced by 2006). The type received Polish certification in March 1996, and US FAR Part 23 certificate on 19 March 2004. Apart from the Skytruck, PZL Mielec developed a family of militarized light transport and maritime reconnaissance planes for the Polish Air Force and Polish Navy in the 1990s, with original PZL-10S engines, named PZL M28B in the Air Force and Bryza in the Navy. From 2000, newly produced M28Bs started to be equipped with five-blade propellers as well. PZL Mielec was bought by  Sikorsky in 2007. Purchased primarily to produce helicopter structures, the company also produces 10 M28s per year. Sikorsky's current owner, Lockheed Martin, has marketed it to the governments of Indonesia, Jordan, Poland, Venezuela, Vietnam, the U.S. and commercial operators. Split equally between commercial and military applications, it competes with the Viking Air Twin Otter, the Let 410 and the Dornier 228. Design. The M28 is a twin-engined high-wing strutted monoplane with an all-metal airframe, twin vertical fins and a tricycle fixed landing gear. If an engine fails, a spoiler forward of the aileron opens automatically on  the opposite wing. This limits the wing drop to 12° in five seconds instead of 30°. It is capable of Short takeoff & landing (STOL) and hot and high altitude operations. Aerodynamically deployed leading edge slats when approaching stall speed enable a low stall speed and while the certification landing field is , PZL has demonstrated landing in . Inlet air ducts inertial separators and inverted configuration of the PT6 and the high wing configuration protect the engines and propellers against foreign object damage for unprepared runways operations. Multiple configurations are available: a 19-passenger airliner with 2-1 seating and  an underbelly luggage pod; a cargo aircraft with a hand-cranked hoist option; the most common combi; a VIP transport; a medevac for six litters and seven seats; a search-and-rescue version; a 17-seat paratrooper drop version; an 18-passenger utility cabin and an aerial firefighting version is considered. Two people can switch between passenger and cargo configurations in 7 min. Its inward opening rear doors allow for cargo drops and utility operations as well as the passenger boarding. It can take off in at the MTOW. Maximum payload is , it can carry over or with full fuel  over . Operational history. 176 An-28s and M28s in all variants were built in Poland by 2006. Most numerous users are former Soviet civil aviation and the Polish Air Force and Navy (about 25 as of 2006), smaller numbers are used by the Polish civil aviation and in the United States, Nepal, Colombia, Venezuela, Vietnam and Indonesia. On 4 November 2005, a Vietnamese Airforce M28 crashed in Gia Lam district, Hanoi. All three crewmembers were killed. On 12 February 2009, The weekly periodical "Air Force Times" reported that the Air Force Special Operations Command (AFSOC) would receive 10 PZL M28 Skytrucks  in June 2009. These aircraft carry the U.S. Air Force model design series (MDS) designation of C-145A Skytruck. In 2011 one aircraft crash landed in Afghanistan and was damaged beyond repair. 11 of AFSOC's C-145As were retired in 2015. In 2016, three were sent to Kenya, two to Costa Rica, two to Nepal, and two to Estonia.