TYPE: Twin-turboprop transport.

PROGRAMME: Westernised development of the Antonov An-28, with Polish power plant and avionics replaced by P&WC PT6A-65B turboprops, Hartzell five-blade propellers and Bendix/King nav/com, weather radar and other equipment. Prototype conversion (SP-PDF) begun early 1991; first flight July 1993; Polish temporary type certificate to FAR Pt 23 Amendment 34 granted March 1994; permanent certificate March 1996, permitting MTOW increase to 7,000 kg (15,432 lb) for versions 01 and 02; subsequently certified to FAR Pt 23 Amendment 42 for increased gross weight version 05 (7,500 kg; 16,534 lb), a prototype of which was completed in 1996.

CURRENT VERSIONS: M2B 05 Skytruck: As described.
M28B Bryza: Amended designation of current production military An-28s; described separately.
M28 03/04 Skytruck Plus: Provisional designation for stretched version; described separately.

CUSTOMERS: First customer delivery (HK-4066X to Latina de Aviación of Colombia) made in January 1996; firm orders totalled 12 at that time, including six for Venezuelan National Guard (deliveries to which began in December 1996); equip Air Detachment 5 at Caracas (four), AD 3 at Maracaibo (one) and AD 9 at Puerto Agoucho (one). One delivered to Aerogryf in Poland in mid-1996; and one to USA (subsequently to Honduras) in 1997; one to Venezuelan civil operator in 2000, but lost in July 2001. Venezuelan National Guard order subsequently (1997) increased to 12, second-batch deliveries beginning mid-1999 and completed (with single M28 02 Executive) in 2000. Twelve M28 05 ordered by Venezuelan Army; first deliveries April 2000; completed in 2001. One delivered to Royal Nepal Army on 18 September 2002 for 11th Brigade at Kathmandu.

DESIGN FEATURES: Inherited An-28's ability to operate from short, austere airfields; added Western engines and avionics to improve export sales prospects. Braced wings; will not stall because of action of automatic slats. Short stub-wing extends from lower fuselage to carry main landing gear and support wing bracing struts, curving forward and downward at front to serve as mudguards; underside of rear fuselage upswept, incorporating clamshell doors for passenger/cargo loading; twin fins and rudders, mounted on inverted-aerofoil, no-dihedral fixed incidence tailplane.
Wing section CAHI (TsAGI) R-II-14; thickness/chord ratio 14 per cent; constant chord, non-swept, no-dihedral centre-section, with 4° incidence; tapered outer panels with 2° dihedral, negative incidence and 2° sweepback at quarter-chord.

FLYING CONTROLS: Manual. Single-slotted mass and aerodynamically balanced ailerons (port aileron has trim tab), designed to droop with large, hydraulically actuated, two-segment double-slotted flaps; electrically actuated trim tabs in elevator have manual back-up; twin rudders each with electrically actuated trim tab; automatic leading-edge slats over full span of wing outer panels; slab-type spoiler forward of each aileron and each outer flap segment at 75 per cent chord; fixed slat under full span of tailplane leading-edge. If an engine fails, patented upper surface spoiler forward of aileron on opposite wing is opened automatically, resulting in wing bearing dead engine dropping only 12° in 5 seconds instead of 30° without spoiler; patented fixed tailplane slat improves handling during high angle of attack climb-out; under icing conditions, if normal anti-icing system fails, ice collects on slat rather than tailplane, to retain controllability.

STRUCTURE: Mostly metal; duralumin ailerons with fabric covering; duralumin slats with CFRP skins; CFRP spoilers and trim tabs. Air intakes lined with epoxy laminate. Two-spar wing with integral fuel tanks between spars.

LANDING GEAR: Non-retractable tricycle type, with single wheel and PZL oleo-pneumatic shock-absorber on each unit. Main units, mounted on small stub-wings, have wide tread balloon tyres, size 720x320, pressure 5.50 bar (80 lb/sq in). Steerable (±50°) and self-centring nosewheel, with size 6.5-10 Goodyear tyre, pressure 6.00 bar (87 lb/sq in) or 595x185-280 Stomil (Poland) tyre, pressure 3.50 bar (51 lb/sq in). Multidisc, anti-lock hydraulic brakes on main units, and inertial anti-skid units. Reinforced landing gear and brakes optional. Minimum ground turning radius 16.00 m (52 ft in). Ski gear under development.

POWER PLANT: Two 820 kW (1,100 shp) Pratt & Whitney Canada PT6A-65B turboprops, each driving a Hartzell HC-B5MP-3D10876ASK five-blade, fully feathering propeller with reverse pitch. Two main fuel tanks in outer wings, each 660 litres (174 US gallons; 145 Imp gallons); two auxiliaries in wing centre-section, each 290 litres (76.6 US gallons; 63.8 Imp gallons); two auxiliary tanks in outer wings, each 189 litres (49.9 US gallons; 41.6 Imp gallons); total wing fuel thus 2,278 litres (602 US gallons; 501 Imp gallons). Auxiliary tanks gravity-filled; main tanks by pressure or gravity. Additional fuel can be carried in tank in main cabin. Oil capacity 16 litres (4.2 US gallons; 3.5 Imp gallons) per engine.

ACCOMMODATION: Pilot and co-pilot on flight deck, which has bulged side windows and electric anti-icing for windscreens, and is separated from main cabin by bulkhead with connecting door. Dual controls standard. Jettisonable emergency door on each side. Standard cabin layout of passengers version has seats for 19 people, with seven single seats on port side and six double seats on starboard side of aisle, at 72 cm (28 in) pitch. All seats easly foldable or removable for carriage of cargo. Aisle width 35.4 cm (13.9 in). Five passenger windows each side of cabin. Seats fold back against walls when aircraft is operated as a freighter or in mixed passenger/cargo role, seat attachments providing cargo tiedown points. Hoist of 500 kg (1,102 lb) capacity able to deposit cargo in forward part of cabin. Alternative interior configurations for 17 parachutists; or six stretchers, eight seated casualties and two medical attendants.
Entire cabin beated, ventilated, soundproofed and, optionally, air conditioned. Inward/upward-opening, hydraulically operated doors for passenger and cargo loading. Emergency exit on each side, plus a third aft of flight deck. Optional ventral pannier, increasing baggage/cargo capacity by 300 kg (661 lb).

SYSTEMS: No pressurisation or pneumatic systems. Hydraulic system powered by two engine-driven pumps, pressure 147 bar (2,132 lb/sq in), for flap, spoiler and (where fitted) cargo ramp actuation, mainwheel brakes and nosewheel steering, with emergency back-up system for spoiler extension and mainwheel braking. Optional air conditioning system, electrically powered with ground power supply back-up, reduces ambient temperatures of up to 40°C (104°F) by 10 to 12°C (18 to 22°F).
Primary electrical system in three-phase AC, with two 28 V DC 12 kW engine-driven starter/generators; two 200/115 V, 400 Hz, 1,500 VA inverters as secondary supply for windscreen heating. Two 26 Ah Ni/Cd batteries.
Electric anti-icing of flight deck windscreens, propellers, spinners and pitot heads, sufficient for short exposure to icing conditions. Oxygen system standard for crew, optional for passengers. No APU.

AVIONICS: Standard Gold Crown suite by Bendix/King.
Comms: Two KTR 908 VHF radios; two KMA 24 H70 audio selector intercoms; MST 67A transponder and encoding altimeter. Optional KHF 950 HF radio.
Radar: Optional RDR-2000 digital weather radar.
Flight: Navigation system based on two KNR 634 VOR/LOC/GS/MKR receivers for VOR/DME navigation, with two EFS 50 EHSI; two KDF 806 ADF; LCR 92S12 laser gyro; two EFS 50 EADI. Optional KLN 900 GPS and FDR, KFC 325 AFCS and KCP 220 computer.