In December 1994, the project had proceeded to ground testing of a non-flying prototype. Subsequently, a pair of flight-capable prototypes were assembled to support the development program. The first prototype was planned to perform an initial flight in January 1995, however this was delayed due to vibration issues during engine runs. On 26 October 1996, the SW-4 was reported as having performing its first flight; an official first flight was conducted on 29 October 1996. By May 2002, the two prototypes had accumulated a total of 640 flight hours. PZL-Swidnik targeted US Federal Aviation Administration (FAA) FAR Part 27 certification for the SW-4. it was believed that the program should be capable of producing production models by 1999.