What happened
On the morning of 8 September 2023, a Robinson R44 Raven II helicopter, registered ZS-RKK, conducted a short private flight between Rietfontein Farm and Prins Farm in the North West province. The flight, operated under Part 91 regulations, was intended to be a brief 10-minute trip. Upon reaching the destination, the pilot landed the aircraft in a field of tall grass to inspect a group of antelope.
Shortly after the engine was shut down, the hot exhaust system ignited the surrounding dry vegetation. The pilot attempted to suppress the flames using an onboard portable fire extinguisher, but the fire quickly became uncontrollable. To avoid a potential explosion, the pilot retreated to a safe distance. Although the pilot and a local farmer eventually managed to douse the field fire, the Robinson R4/4 Raven II was destroyed by the flames.
The investigation
An investigation by the SACAA AIID established that the pilot's medical certificate had expired, rendering his license invalid at the time of the incident. While the aircraft was airworthy and possessed a valid Certificate of Airworthiness, investigators discovered that the helicopter was not equipped with the exhaust muffler and tailpipe shielding kit required by Service Bulletin SB-46.
Furthermore, the investigation noted that the pilot's right-front and cabin doors had been removed for the duration of the flight. The investigation also highlighted that the pilot had disregarded specific safety instructions found in the Pilot's Operating Handbook (POH), which explicitly warn against landing in tall, dry grass due to the high temperature of the exhaust system.
Findings
- The primary cause of the accident was the pilot landing the helicopter in tall, dry grass, which ignited upon contact with the hot exhaust.
- The pilot failed to adhere to safety notices and tips in the POH regarding landing environments.
- The aircraft lacked the mandatory muffler and tailpipe shield kit specified in Service Bulletin SB-46.
- The pilot was operating with an invalid medical certificate.