PZL M28 Skytruck

Design and 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 the Ukraine. 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, 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.

Description

It is a twin-engined high-wing strutted monoplane of all-metal structure, with twin vertical fins and a robust tricycle fixed landing gear, featuring a steerable nose wheel to provide for operation from short, unprepared runways where hot or high altitude conditions may exist. The M28 is best suited for passenger and/or cargo transportation.

Short takeoff & landing (STOL) capability

Excellent flight handling at low airspeeds

High useful load, mission versatility

Unpaved airstrip operating capability

Easy access through rear cargo door, fitted with a hoist for cargo loading and relocation inside the cabin

High-wing arrangement for protection of engines and propellers against damage when operating from unpaved airstrips

Easy and quick conversion of the cabin interior configuration

Low operating cost

PT6 engines of inverted configuration for efficient protection against foreign object ingression owing to inertial separators installed inside air inlet ducts.

While of conventional design, one notable feature of the An-28 is that it will not stall, due to its automatic slats. An engine failure that would usually induce the wing to drop 30° is combated by an automatic spoiler forward of the aileron that opens on the opposite wing, restricting wing drop to 12° in five seconds.

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 USA, Nepal, Colombia, Venezuela, Vietnam and Indonesia.

On 4 November 2005, a Vietnamese Airforce M28 crashed in Gia Lam district, Hanoi. All three crewmembers died.

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.

On 28 October 2010, an Indonesian Police-operated M28 crashed in the Nabire region of the Indonesian state of Papua, killing five people.

On 3 December 2016, an Indonesian Police-operated M28 crashed into the sea near the island of Pulau Senayang in the Riau Islands province of Indonesia with thirteen people on board, all presumed dead.

Airframe Variants

PZL An-28

Original variant build under Antonov licence, with PZL-10S (licence TV-10B) engines.

PZL M28 Skytruck

Development variant with redesigned fuselage and wings, new Pratt & Whitney Canada engines, new (western) avionics, 5-blade rotors, and some other minor changes.

PZL M28B Bryza

Militarized variants used by Polish Air Force and Polish Navy, similar to Skytruck, but with PZL-10S engines.

PZL M28+ Skytruck Plus

Prototype of new lengthened variant with more internal space, not in production.

C-145A

Variant flown by USAF Special Operations Warfare Center. Similar to Skytruck, but with Pratt and Whitney PT6A-65B Turboprops. The USAF has started retiring the aircraft, with the first aircraft, AF Ser. No. 08-0310, delivered to the 309th Aerospace Maintenance and Regeneration Group at Davis-Monthan AFB, Arizona on 28 May 2015. By June 2015 eleven out of 16 aircraft were stored.

Variants in use by Polish Military

PZL An-28TD

Basic transport variant. Used mainly for transport and paratroop training (2 built).

PZL M28B

Several similar improved transport variants featuring avionics and airframe upgrades: Bryza 1TD (2 built), M28B (3 built), M28B Salon (1 built), M28B TDII, TDIII and TDIV (2 built of each).

PZL M28B Bryza 1R

Maritime patrol and reconnaissance variant (equipped with: 360° Search and Surveillance Radar ASR-400, Link-11 datalink). Used mainly for sea border patrolling, search and rescue operations and protection of the national economical sea zone (7 built).

PZL M28B Bryza 1E

Maritime ecological reconnaissance and patrol variant (2 built).

PZL M28B Bryza 1RM bis

Maritime patrol and reconnaissance variant with submarine detection capability, of 2004 (equipped with: 360° Search and Surveillance Radar ARS-800-2, ejection of single-use hydro-acoustic sonobuoys, Thermal Imaging System (FLIR), magnetic anomaly detector, Link-11 datalink). Used mainly for sea border patrolling, search and rescue operations and protection of the national economical sea zone (1 built as of 2006).

PZL M28 05 Skytruck

Maritime patrol and SAR variant for the Polish Border Guard, of 2006 (equipped with Search and Surveillance Radar ARS-400M and FLIR system) (1 built as of 2006).

Operators

 Guyana

JAGS Aviation Guyana (1)

 Indonesia

Indonesian National Police (4)

 Jordan

Royal Jordanian Air Force (3)

   Nepal

Nepalese Army Air Service (2)

 Poland

Polish Air Force (25)

Polish Navy (16)

Polish Border Guard (1)

 Suriname

Blue Wing Airlines

 United States

United States Air Force

Air Force Special Operations Command

318th Special Operations Squadron (2007-2013)

6th Special Operations Squadron (2012-)

Air Force Reserve Command

711th Special Operations Squadron (2013-)

Sierra Nevada Corporation (2)

Arizona Department of Public Safety (2)

 Venezuela

Venezuelan Army (12)

Venezuelan National Guard (13)

 Vietnam

Vietnam People's Air Force (11)

Specifications (PZL M28)

Data from Jane's All The World's Aircraft 2003–2004

General characteristics

Crew: 2

Capacity: 19 passengers (17 paratroopers)

Payload: 2,300 kg (5,070 lb)

Length: 13.10 m (42 ft 11¾ in)

Wingspan: 22.06 m (72 ft 4½ in)

Height: 4.90 m (16 ft 1 in)

Wing area: 39.72 m² (427.5 ft²)

Empty weight: 4,100 kg (9,309 lb)

Max. takeoff weight: 7,500 kg (16,534 lb)

Powerplant: 2 × Pratt & Whitney Canada PT6A-65B turboprops, 820 kW (1,100 shp) each

Performance

Maximum speed: 355 km/h (191 knots, 220 mph)

Cruise speed: 270 km/h (146 knots, 168 mph) at 3,000 m (9,840 ft) (econ cruise)

Stall speed: 123 km/h (67 knots, 77 mph) (flaps up)

Range: 1,500 km (809 nmi, 932 mi) with max fuel

Endurance: 6 hr 12 min

Service ceiling: 7,620 m (25,000 ft)

Rate of climb: 11 m/s (2,165 ft/min)

Accidents and incidents

On 3 December 2016, a PZL Skytruck belonging to the Indonesian National Police crashed onto the ocean in Dabo, Riau Islands while carrying 13 people. All 13 people on board were killed in the accident. Eyewitnesses stated that the aircraft had suffered an in-flight failure and claimed that the engine of the plane was emitting black smoke.