What happened
On 20 May 2017, a Robinson R22 helicopter, registration ZS-RIT, was engaged in agricultural spraying operations in the Port Shepstone area of KwaZulu-Natal. The pilot was tasked with treating six sugar cane fields. After successfully completing five fields, the aircraft departed from a temporary loading zone at approximately 1140Z to begin the final section of the mission.
The flight proceeded from east to west at a low altitude of approximately 6 feet above the crops. As the pilot reached the end of the field and attempted to climb to initiate a turning maneuver, the aircraft's main rotor blades struck high-tension electrical cables spanning the area. The impact caused the rotor blades to flex downward with enough force to sever the tail boom into two distinct pieces. Following the structural failure, the pilot lost control of the aircraft, which entered an uncontrollable spin and crashed into a nearby stream approximately 60 meters from the initial point of impact. The pilot sustained fatal injuries, and the aircraft was destroyed.
The investigation
SACAA AIID investigators examined the wreckage, the flight history, and the environmental conditions at the site. The investigation confirmed that the aircraft was airworthy, properly maintained, and within weight and balance limits at the time of departure. The pilot held a valid commercial pilot license with the necessary agricultural ratings and met the operator's experience requirements.
Investigators also reviewed the site of the impact, noting that the electrical pylons were spaced approximately 600 meters apart. While a map of the area indicated the presence of power lines, the investigation focused on the visibility of the cables themselves and the pilot's approach to the field. The weather at the time of the accident was clear with calm winds.
Findings
- The pilot was performing the mission for the first time in these specific fields and lacked familiarity with the local terrain.
- The pilot did not perform adequate aerial surveillance of the area prior to commencing the spraying maneuver.
- The high-tension electrical cables were not equipped with red and white marker spheres, which could have improved visibility.
- The collision with high-tension electrical cables during the climbing maneuver was the primary cause of the structural failure and subsequent crash.