History of Flight
On 26 December 2016, a Robinson R44 II helicopter (registration ZS-HXX) departed Stellenbosch Airfield (FASH) at 09:40Z on a private flight to Worcester Airfield (FAWC). The pilot reported that the start and lift-off were uneventful. A few minutes after take-off, while passing 2000 feet above ground level (AGL) over Stellenbosch town, the governor warning light illuminated. The pilot checked all circuit breakers and attempted to switch the governor on and off, but the warning light remained on. The pilot then decided to return to Stellenbosch Airfield.
On arrival, the pilot descended on the eastern side of the airfield and joined the right downwind for runway 19. The pilot managed to keep the rotor RPM in the green range using the throttle. During the turn for final approach for runway 19, the low rotor RPM warning sounded. As the helicopter was low, the pilot opted to execute an emergency landing on De Zalze Golf Estate, located 0.5 nautical miles northeast of Stellenbosch Airfield.
During the landing, the helicopter touched down hard and rolled onto its right-hand side. The main rotor blades struck the ground as the helicopter came to rest. The pilot and passenger disembarked without injury.
Investigation Revealed
The pilot held a valid Private Pilot Helicopter licence (valid from 31 July 2009 to 30 July 2019) and a valid medical certificate (expiry 30 June 2017). The pilot had 585.9 total flying hours, with 253.2 hours on type, and was 53 years old.
The helicopter was manufactured by the Robinson Helicopter Company and had accumulated 231 airframe hours at the time of the accident. The last annual inspection was carried out on 21 October 2016 at 226.7 hours; the helicopter had flown 4.3 hours since then. The Lycoming IO-540-AE1AS engine (serial number L-33739-48E) had 231 hours since new. The main rotor blade (serial number 5935) hours since new were unknown.
The helicopter sustained damage to the skids, main rotor blades, and tail rotor. The pilot and passenger diverted due to the governor failure, and the low rotor RPM warning occurred during the final approach turn. The pilot subsequently performed a forced landing.
Conclusion
The probable cause of the accident was an unsuccessful forced landing following a low rotor RPM. A contributory factor was governor failure.
Safety Recommendations
None were issued.