What happened
On 11 September 2008, an Air Tractor AT-502B, registration ZS-NZU, was performing agricultural spraying operations in the Caledon district of the Western Cape. After successfully completing five spray loads and refuelling with 200 litres of fuel and 1500 litres of chemicals, the pilot commenced a sixth run.
At approximately 0900Z, a witness near the site heard a loud noise followed by a dull explosion and observed a cloud of dust. Upon reaching the location, the witness discovered the aircraft overturned in a cornfield on the Franskraal farm. The pilot, who was the sole occupant, sustained fatal injuries due to the high impact forces of the crash.
The investigation
SACAA AIID investigators examined the wreckage and found that the aircraft had struck the ground on an uphill section of rocky terrain. The impact caused the aircraft to bounce and eventually come to rest in an inverted position. While the aircraft was destroyed by the impact, there was no evidence of a pre-impact fire or mechanical failure. The engine and flight controls were found to be in the correct configuration for flight.
Investigators recovered significant bird remains and feathers inside the cockpit, along with a piece of the shattered windscreen. A Blue Crane carcass was located approximately 53 metres from the wreckage. Data from the aircraft's AG-NAV 2 navigation system showed that the system stopped transmitting guidance information approximately 370 metres before the final impact, suggesting a disruption during the collision.
Findings
- The primary cause of the accident was the aircraft colliding with the ground during an agricultural spraying mission.
- A significant contributing factor was a collision with a Blue Crane in flight, which likely damaged the windscreen and disrupted the navigation system.
- The accident was not survivable due to the intense vertical and longitudinal loads placed on the cockpit canopy during impact.
- Although the aircraft was equipped with a shoulder harness, the pilot was only wearing the lap strap at the time of the accident.