What happened
The aircraft was engaged in agricultural operations, specifically spraying melons, when the incident occurred. During a standard swath run, the pilot initiated a pull-up maneuver to transition between spray passes. However, the aircraft failed to respond as expected because the flight controls became jammed.
In an effort to free the control surfaces and regain authority over the aircraft, the pilot attempted to manipulate the controls manually. During this struggle, the right main landing gear struck the ground. The pilot later reported that the jamming was caused by a string used as a gust lock that had wedged itself into the stick control mechanism. Despite the pilot's attempts to release the gust lock line, the airplane collided with the ground before the obstruction could be cleared.
The investigation
Post-accident examination and pilot statements indicated that the primary mechanical failure was not due to system malfunction but rather human error in pre-flight preparation. The string serving as a gust lock had not been properly secured prior to departure. This oversight allowed the string to become dislodged during flight, where it wedged into the control stick, effectively locking the controls and preventing the pilot from maneuvering the aircraft.
Findings
The investigation determined that the accident was caused by the improper securing of the gust lock before takeoff. The failure to ensure all ground handling devices were removed or properly stowed led to the in-flight jamming of the flight controls. This loss of control prevented the pilot from completing the pull-up maneuver, resulting in a collision with the terrain.
Safety message
Pilots must verify that all gust locks and control immobilization devices are completely removed or secured away from the control mechanism prior to engine start. Agricultural pilots should implement strict pre-flight checklists that specifically address ground handling equipment to prevent similar in-flight control restrictions.