What happened
On December 12, 2004, at approximately 16:15 UTC, two light aircraft collided in mid-air near a cement plant in the municipality of Mataporquera, Cantabria. The first aircraft, a Scheibe SF-25E (registration EC-ESI), had departed from the Herrera de Pisuerga airfield in Palencia, intending to fly to Santander. The second aircraft, a Tecnam P92SE (registration EC-DL5), had departed from Cillamayor for a local flight.
Witnesses observed the two aircraft flying in parallel and in very close proximity for a period ranging from 20 seconds to one minute. The flight was steady and level, with no unusual maneuvers noted prior to the impact. The collision occurred at an altitude estimated between 150 and 300 meters. Following the impact, the EC-DL5 lost its left wing and tail assembly, causing it to fall almost vertically. The EC-ESI suffered structural damage to its wing and cockpit canopy, resulting in a descending circular flight path before striking the ground. Both aircraft were completely destroyed, and the four occupants—two pilots and two passengers—were killed upon impact with the terrain.
The investigation
The CIAIAC investigation examined the wreckage of both aircraft and interviewed five eyewitnesses. The inspection of the debris confirmed that the impact occurred when the aircraft were flying parallel, with the EC-ESI on the left and the EC-DL5 on the right. The investigation found that the left wing edge of the EC-DL5 struck the fuselage of the EC-ESI near the registration marks, subsequently striking the right wing of the EC-ESI and causing a significant loss of surface area.
Investigators found no evidence of mechanical failure in either aircraft prior to the collision. Meteorological conditions were reported as excellent, with high visibility and light winds. Radio communications between the two pilots were noted shortly after takeoff, but no further contact was recorded before the accident.