In 1986, Ukrainian aircraft concern Antonov (then part of the Soviet Union) introduced to market the Antonov An-28, a light-class, twin-engined turboprop transport aircraft. One-hundred ninety-one were ultimately built in four major versions and both civilian and military operators took notice - from Armenia and Angola to the Venezuela and Vietnam. Among the list of operators became Poland and the country eventually took on local, licensed production of the series which led to a locally-refined model as the M.28 "Skytruck" by PZL Mielec.
The original Antonov An-28 was recorded a first-flight on July 22nd, 1984 and early production models still carried 2 x PZL-10S turboprop engines (the TVD-10B series under license) driving three-bladed propeller units as well as the An-28 designation.
At the core of the An.28's success was its high-wing arrangement which added natural lifting properties and improved on short-field operations. A rugged understructure and reinforced undercarriage also gave good rough-field operation. Beyond this, the An.28 was given a relatively compact footprint as transports go and held a deep fuselage with raised empennage to facilitate cargo movement into, out of, and around the aircraft. It was these qualities that have allowed the aircraft to continually find favor with civilian and military groups including special forces outfits around the world.
In addition to the stated, the aircraft also sported excellent handling and a rear cargo door allows for unfettered access to the hold within the fuselage. The interior could also be converted to suit various roles including passenger hauling. An anti-stall feature was also built-in.
After the fall of the Soviet Empire in 1991, PZL was free to maximum the An-28 for Western customers and took to installing a Western avionics fit, Western instrumentation and Pratt & Whitney Canada turboprop engines. The aircraft now flew with 2 x PT6A-65B engines of 1,100 horsepower and these drove five-bladed Hartzell propeller units. It is in this guise that the An-28 became the PZL M.28 "Skytruck" and achieved a first-flight on July 24th, 1993. Certification followed in March of 1996.
The M.28 seats a crew of two and can fit an additional nineteen passengers with a properly-equipped cabin. Its payload capability is 5,070lb. Overall length of the aircraft is 42.11 feet with a wingspan of 72.4 feet and a height of 16 feet. Empty weight is 9,310lb against an MTOW of 16,535lb. Power is from 2 x Pratt & Whitney Canada PT6A-65B turboprop engines rated at 1,100 horsepower each. Performance specs include a maximum speed of 220 miles per hour, a cruise speed of 170 mph, a range out to 930 miles and a service ceiling up to 25,000 feet. Rate-of-climb is 2,165 feet-per-minute.
The modern Polish Air Force and Navy services use a militarized form of the M.28 as the M.28B "Bryza" ("Sea Breeze"). These fly with 2 x PZL-10S series engines. Other Polish variants include the An.28TD basic transport, the M.28B improved model, the M.28B Bryza 1R maritime patroller, the M.28B Bryza 1E maritime ecological reconnaissance patroller, the M.28B Bryza 1RM bis maritime patroller (with submarine hunting functionality) and the M.28 05 Skytruck for the maritime patrol and Search and Rescue (SAR) roles.
The United States Air Force (Special Operations Warfare Center) is perhaps the most notable foreign Skytruck operator and fields their fleet (of sixteen aircraft) with 2 x Pratt & Whitney PT6A-65B turboprop engines. The type, designated locally as the "C-145A", is used in special mission roles but the line is being phased out as of this writing (some eleven are in storage as of 2017). C-145As has operated in the Afghanistan Theater of War.
The M.28+ "Skytruck Plus" is a proposed, extended fuselage model which has not been adopted.