What happened
On September 26, 2006, a PIPER PA-36-400 BRAVE, registration EC-ENY, was performing agricultural spraying operations over olive groves in the municipality of Castillo de Locubín, Jaén. The aircraft was engaged in its fourth flight of the day, executing a mission to spray a hillside slope oriented toward the southwest.
During the mission, the pilot had previously completed an initial pass with a full hopper, descending from the upper part of the property. For the subsequent pass, the aircraft was carrying approximately one-third of its hopper capacity. The pilot initiated this second pass from a low altitude at the bottom of the slope, believing the reduced weight would provide sufficient climb performance to ascend the terrain. However, the aircraft's climb gradient was shallower than the slope of the hillside.
As the aircraft struggled to maintain altitude, the pilot applied maximum power and attempted to maneuver to avoid the terrain, but no clear escape route was found. Approximately 150 meters before impact, the pilot activated the emergency lever to jettison the remaining load. Despite this effort, the aircraft struck olive trees on the hillside. The pilot survived the impact uninjured, but the aircraft sustained major damage.
The investigation
The CIAIAC examined the flight dynamics and the operational procedures used during the spraying mission. The investigation focused on the interaction between the aircraft's performance, the terrain's steepness, and the pilot's decision-making regarding the flight path. The investigators analyzed the risks inherent in low-altitude agricultural operations, specifically how the combination of rugged topography, continuous weight changes due to chemical discharge, and low-altitude maneuvering significantly reduces safety margins and reaction time.
Findings
- The primary cause of the accident was the impact with the hillside because the terrain's slope exceeded the aircraft's climb capabilities.
- The pilot initiated the climb maneuver from an altitude that was too low to ensure the clearance of obstacles.
- The flight path was planned without a viable escape route or an alternative maneuver to avoid the terrain.
- The pilot's decision to start the pass from the bottom of the slope, rather than descending from the top of the hill, prioritized operational efficiency over safety.
- The investigation noted that while starting from the top of the slope would have been less efficient, it would have significantly increased operational safety by providing a better margin for error.