A decision to redesign the main rotor head resulted in considerable delays to the flight testing program; during this time, other changes were made to the rotorcraft, included the horizontal stabilizer being extended and improvements of the hydraulic systems. In 2002, the first production model SW-4, which was equipped with the Rolls-Royce engine, was approaching receipt of certification from the Polish civil aviation authority. Certification for use in other markets is to be made upon customer request, targeting a $700,000 price at the time. On 1 October 2002, serial production of the SW-4 formally began. On 27 September 2007, type certification from the European Aviation Safety Agency (EASA) was received. Following on from the certification of the Rolls-Royce model, PZL Swidnik pursued a separate re-certification for a modified SW-4 fitted with a Pratt & Whitney Canada PW200 powerplant as an alternative option.