What happened
On 13 December 2017, a Robinson 44 II helicopter, registration ZS-ZZF, departed from Thabo Lesodi Farm in the Limpopo Province for a short flight to a neighboring farm approximately 32 km away. The pilot, the sole occupant of the aircraft, initially flew north before banking left to pass over a farmhouse to greet friends, a routine part of the flight pattern.
During this low-level maneuver, witnesses at the farmhouse observed the engine making an unusual noise, followed by the aircraft pitching nose-down and yawing to the left. The engine subsequently ceased running, leaving only the sound of the rotors. The helicopter descended rapidly, striking trees approximately 65m from the house. The impact caused the aircraft to bounce and nose over, ultimately resulting in the total destruction of the helicopter. The pilot sustained serious injuries and required medical evacuation by air.
The investigation
An investigation by the SACAA AIID established that the engine failure was the result of fuel starvation caused by water contamination. Although the pilot had noted and drained a small amount of water during the pre-flight inspection, post-accident analysis of the main and auxiliary fuel tanks, as well as the gascolator, revealed a substantial amount of water remained. It is believed that water may have been introduced via the fuel bowser used for refueling on the farm.
Investigators also examined the flight conditions and the pilot's actions. The aircraft was flying at a low altitude, approximately 200ft, at the time of the engine stoppage. The investigation noted that the pilot's attempt to execute a forced landing was likely compromised by the low altitude and the need to avoid the farmhouse, which left insufficient time to manage rotor RPM and airspeed effectively. Furthermore, a slight tailwind may have further hindered the pilot's ability to maintain necessary rotor RPM during the emergency.
Findings
- The primary cause of the engine stoppage was fuel contamination from water.
- The pilot was unable to successfully execute a forced landing due to the low altitude and the immediate need to avoid obstacles.
- The engine was not running at the time of impact, as evidenced by the minimal damage to the alternator's rotating section.
- The pilot's flight records and fuel logs were not up to date in the flight folio, which was a deviation from regulatory requirements.