What happened
On August 13, 2008, an Air Tractor AT-401, registration EC-JIF, was performing an agricultural spraying mission at the La Moncloa farm in Valdecaballeros, Badajoz. The aircraft was operating from a 600-meter grass runway. Due to the runway's upward slope, the pilot elected to use runway 30 for the takeoff.
The takeoff was performed using the short-field procedure with a full hopper load. While the takeoff roll and rotation initially proceeded normally, the aircraft experienced an uncommanded left wing roll at an altitude of approximately 1.5 meters. In an attempt to correct the roll, the pilot executed an emergency discharge of the chemical load; however, this action intensified the banking motion. The aircraft subsequently pitched up, triggering a stall warning. The aircraft continued its flight path, striking a perimeter fence and eventually impacting a row of pine trees with the left wing before coming to a stop. The pilot escaped the aircraft without injury.
The investigation
The investigation examined the aircraft's weight, takeoff configuration, and the physical evidence at the scene. The aircraft's takeoff weight was determined to be 7,169 lb, which was within the demonstrated maximum weight limits for the type. Post-accident inspections confirmed that the flight controls, including aileron, elevator, and rudder, were moving freely and that there were no failures in the control linkages. The flaps were found to be symmetrically extended.
Findings
- The aircraft was operating within its certified weight limits.
- The pilot correctly implemented the short-field takeoff configuration, including 10 degrees of flaps.
- The investigation established that the uncommanded left wing roll likely occurred because the pilot attempted to gain altitude by pulling back on the control column, which may have induced a stall on the left wing.
- The emergency discharge of the load, intended to stabilize the aircraft, actually exacerbated the roll and caused the aircraft to pitch up, leading to a more pronounced stall condition.