What happened
On July 17, 2001, at approximately 11:30 local time, a Grumman G164B, registration EC-EDD, was performing agricultural spraying operations at Finca Pericón, near Vejer de la Frontera, Spain. The aircraft was conducting its sixth flight of the day over the same area.
During the takeoff roll on a 500-meter unpaved strip, the pilot noted that the aircraft was taking longer than usual to rotate. In an attempt to assist the aircraft in lifting off before the end of the runway, the pilot activated the emergency discharge system to jettison the chemical load. While this action successfully reduced the aircraft's weight and allowed it to leave the ground, the sudden change in weight and center of gravity caused the aircraft to stall. The aircraft subsequently descended into an adjacent rice field. The pilot was uninjured, but the aircraft sustained damage to the spraying equipment and the lower wing trailing edge.
The investigation
The investigation examined the takeoff performance and the impact of the emergency discharge maneuver. Investigators analyzed the aircraft's weight and balance, the environmental conditions, and the pilot's decision-making during the takeoff roll. The inquiry focused on why the aircraft failed to rotate normally despite the load being identical to previous successful flights that day.
Findings
- The pilot likely attempted to rotate the aircraft at a speed below the required threshold, which prevented sufficient lift from being generated.
- The emergency discharge of the chemical load caused an instantaneous reduction in weight, which significantly altered the aircraft's center of gravity and pitch attitude.
- This rapid shift in mass likely caused the aircraft to exceed its maximum angle of attack, leading to an aerodynamic stall.
- While the load quantity remained constant throughout the day, increasing ambient temperatures likely reduced engine performance compared to earlier flights, contributing to the extended takeoff roll.