Incident Description
According to the pilot, the helicopter was operating normally prior to impact, but he could not recall details of the event. A witness reported that the helicopter descended along the canyon wall at an altitude of 40 to 50 feet, slowing its descent as it executed a course reversal toward the landing zone. The nose of the helicopter "dipped," then rose, and the tailboom struck the ground and separated. Following the separation, the helicopter began to "spin out of control."
Witness Accounts
Another observer saw the helicopter "twisting in a horizontal plane, i.e. the tail swinging from side to side" just before impact. A third witness, a helicopter pilot, noted that the wind was light and variable. He heard a rotor blade "slap" and recognized that the helicopter was in a turn. Shortly after, he heard the sound of impact. According to the company's loader, there was no change in engine or rotor sounds prior to the tailboom striking "a small incline of a hill."
Postaccident Examination
A postaccident examination of the helicopter disclosed no evidence of mechanical malfunction.