What happened
On 14 February 2011, an Air Tractor AT 401, registration ZS-NLP, was performing agricultural spraying operations near the Kataza private airstrip in KwaZulu-Natal. After completing a spraying detail on a local farm, the pilot approached the 800-meter grass runway at an indicated airspeed of approximately 70 to 80 mph.
During the landing phase, the aircraft bounced on a section of the runway that was wet. In an attempt to stabilize the aircraft, the pilot applied full throttle; however, the engine failed to respond effectively due to the rapid movement of the throttle lever. Consequently, the aircraft slid down the slope of the runway and underwent a ground-loop. During the maneuver, the tail wheel remained in the locked landing position. The aircraft subsequently sustained substantial damage to its tail section, and the propeller struck the ground when the left wheel locked while the pilot was attempting to taxi forward.
The investigation
SACAA AIID investigators reviewed the flight history, maintenance records, and environmental conditions. The investigation confirmed that the pilot held a valid commercial pilot license and medical certificate, and was properly rated for the aircraft type. Maintenance logs indicated that the Air Tractor AT 401 had been properly maintained, with all mandatory periodic inspections up to date and a valid certificate of airworthiness.
Findings
- The primary cause of the accident was engine failure induced by the pilot's rapid movement of the throttle lever during the landing recovery attempt.
- The pilot lost control of the aircraft following the bounce on the runway.
- A wet runway surface acted as a contributing factor to the initial bounce and subsequent loss of directional control.