What happened
On 20 June 2018, an Air Tractor AT-301, registration ZS-KPC, departed Boland Agricultural High School near Paarl, Western Cape, to perform a scheduled agricultural spraying mission. The flight was being conducted as a Part 137 operation.
While returning to the airfield following the completion of the spraying task, the pilot noticed fluctuations in the fuel flow indicator. This instability was immediately followed by a progressive loss of power. At an altitude of approximately 650 feet above ground level, the engine ceased functioning entirely. The pilot notified ground personnel of the emergency and prepared for a forced landing.
Approximately 2 nautical miles from the intended destination, the pilot executed an emergency landing in an open field. During the touchdown, the main landing gear sank into the soft earth, causing the aircraft to nose over. The impact resulted in the propeller striking the ground. Despite the impact, the pilot sustained no injuries.
The investigation
Investigators examined the aircraft and the circumstances surrounding the power loss. The aircraft, powered by a Walter M601 D turbine engine, had recently undergone a mandatory periodic inspection. Following the incident, the aircraft was transported to a maintenance organization in Bethlehem, Free State, for a detailed technical assessment.
Technical inspections included a borescope examination of the engine internals and various troubleshooting procedures focused on the fuel and engine bleed systems. An engine test run was also conducted at the maintenance facility to replicate the failure.
Findings
- The primary cause of the accident was an unsuccessful forced landing following an engine failure.
- The specific reason for the engine shutdown could not be determined, as the engine operated normally during post-accident testing and no internal faults were found via borescope.
- The landing gear's interaction with the soft terrain caused the subsequent nose-over and propeller damage.
- Damage to the aircraft was localized to the propeller, the nose cowling, the support structure, and the undercarriage.
- Weather conditions at the time of the incident were clear with visual meteorological conditions (VMC) and did not contribute to the event.