Aerial Fertilizer Application Accident Involves Loss of Control After Fence Strike (ZK-CAY)

Operational Context and Takeoff Sequence Flying operations began at 07:30 a.m. following a delay due to unfavorable weather. The aircraft completed twenty-seven fertilizer loads before the pilot and loader driver paused for a 30-minute break, during which the plane was refueled to capacity. Upon resuming operations, the pilot directed the loader driver to load the hopper with the same quantity as before and initiated takeoff from a sloping airstrip. ## Accident Sequence A witness observed that the aircraft took longer to become airborne than during previous takeoffs. The loader driver then saw the plane executing a left turn at an altitude of 30 to 40 feet just beyond the end of the strip, exhibiting a “porpoising” motion. The bank angle increased beyond vertical, and the aircraft crashed in an inverted attitude on the far side of a nearby gully. The impact and intense fire destroyed the aircraft, killing the sole occupant. The accident was not survivable. ## Investigation Findings The official investigation determined that a freshening of the breeze during the break increased the tailwind component on the takeoff run. Combined with a full hopper load and full fuel, the aircraft lacked sufficient distance to become fully airborne. The aircraft flew through a fence at the end of the airstrip in a nose-high attitude, and the impact with a concrete post damaged the left stabilator, wrenching it out of alignment with the fuselage and restricting its free movement. The fertilizer load was not jettisoned. While there was no evidence that the maximum authorized unit weight (MAUW) was exceeded, the aircraft was clearly overloaded for the ambient conditions. The center of gravity remained within permitted limits. Weather conditions were favorable for aerial topdressing, with high cloud, a light breeze, and good visibility. The engine was producing full power until the final impact. ## Probable Cause The investigator concluded that the probable cause was the pilot’s inability to maintain control after damage to the flight control system occurred when the aircraft failed to become airborne and struck a fence at the end of the airstrip.