The SW-4 is powered by a single 335 kW (450 shp) (283 kW/380 shp max continuous rated) Rolls-Royce Model 250C20R/2 turboshaft engine, which drives the rotorcraft's three-blade main rotor and two-blade tail rotor. An alternative engine is provided in the form of the 460 kW (615 shp) Pratt & Whitney Canada PW200/9 turboshaft engine. The main rotor is fully articulated and the rotor blades on both the main and tail rotors are composed of composite materials. The SW-4 uses hydraulic flight controls, the rotorcraft has been promoted as possessing excellent flight controls, and can be flown in both day and night visual flight rules conditions.