History of Flight
On 19 May 2017 at approximately 1430Z, the pilot, accompanied by three passengers, departed from Nampo Park near Bothaville, Free State, on a private flight to De Hoop private farm near Frankfort. The flight was conducted under visual meteorological conditions during daylight hours. According to an eyewitness on Ongegund farm, the helicopter was approaching from the west when a sudden change in engine tone was heard, followed by a rapid descent in a nose-down attitude. The pilot appeared to execute an autorotation, as the nose pitched up shortly before the helicopter struck the ground. The main rotor severed the tail boom on impact.
Injuries and Damage
The helicopter was destroyed by the impact. Two occupants were fatally injured: the pilot and one 14-year-old male passenger. Two other occupants, an adult male passenger and another 14-year-old male passenger, sustained serious injuries and were transported to a hospital. The adult male was hospitalized for 14 days and the 14-year-old for approximately 62 days.
Investigation Findings
Post-wreckage examination revealed that the helicopter had impacted the ground at a high rate of descent, collapsing both skids, nosing over, and coming to rest on its left side. The engine and flight controls showed no malfunctions. The survivor in the left front seat reported hearing a loud bang, after which the pilot mentioned a problem. The clutch light illuminated but no warning sounds were heard. The pilot pushed the cyclic forward during descent, then pulled back and applied full collective before impact. The investigation concluded that the helicopter impacted the ground at a high rate of descent following undetermined engine stoppage.
Probable Cause
The helicopter experienced engine stoppage; the pilot executed autorotation; however, the helicopter was observed pitching nose up and impacted the ground at high velocity. The main rotor severed the tail boom on impact. A contributory factor was undetermined engine failure.