On January 31, 1998, approximately 1400 Pacific standard time, N50499, a amateur-built Sherman Executive helicopter, collided with terrain after in-flight separation of its tail boom and tail rotor while maneuvering, near Stayton, Oregon. The two occupants, a commercial helicopter pilot and the owner (a private pilot) were fatally injured. The helicopter had departed Salem, Oregon, on a training flight for the private pilot. Visual meteorological conditions prevailed at the time of the accident. The wreckage was consumed by fire. There was no ELT onboard the aircraft. Witnesses described the helicopter making about 4 passes over the field at about 500 feet above the surface. On the last pass, there was a hard yaw to the right; the helicopter then straightened out, pitched into a flare, then the tail came up and the main rotor struck the tail-boom. The tail-boom, tail rotor, and bubble canopy separated from the helicopter. The main wreckage was located about 300 feet from those components. The owner-builder had brought the helicopter to Salem to acquire helicopter flight training. The commercial pilot had extensive experience in helicopters, but he did not have a flight instructor certificate. Toxicological testing on both pilots on board the helicopter was negative. Autopsies of the two occupants were performed at Portland, Oregon by Drs. Nikolas J. Hartshorne and Steve Shapiro. The NTSB did not take possession of the aircraft.