What happened
On October 11, 2008, a private Cirrus SR-22 G3-GTS, registration EC-KOJ, departed Huesca Airport for San Sebastián Airport with the pilot and two passengers. The flight proceeded normally until the aircraft crossed the Peñas de Aia mountain range. As the aircraft descended toward the approach path, it encountered increasing atmospheric turbulence.
While flying at approximately 3,000 feet, the aircraft experienced sudden, violent movements. The pilot reported that the right wing lost lift, causing a sharp right turn, followed by a secondary roll to the left that the pilot described as a spin. Fearing a total loss of control at a low altitude, the pilot activated the aircraft's emergency parachute system. The aircraft descended into a wooded area, coming to rest vertically, supported by telephone lines and vegetation. The aircraft sustained important damage to the cockpit, the right wing, and the fuselage, but all three occupants remained uninjured.
The investigation
The investigation examined the meteorological conditions, the pilot's flight planning, and the aircraft's emergency systems. Investigators noted that while the pilot had reviewed METAR and TAFOR reports, the focus was primarily on visibility rather than wind conditions. The pilot did not consult wind maps prior to the flight.
Meteorological data confirmed a strong south-southeast airflow over the region. Specifically, the area near the VOR, located on the western slope of the mountains, is prone to significant turbulence due to leeward effects (lee waves) when winds blow from the south-southeast. The investigation also reviewed the operational limits of the aircraft's parachute, which is designed to stabilize the aircraft in a horizontal position if deployed above 2,000 feet AGL and below 130 knots.
Findings
- The aircraft encountered severe atmospheric turbulence caused by the leeward effect of the Peñas de Aia mountains during the approach to runway 22.
- The pilot's flight planning focused on visibility and did not sufficiently account for the high-velocity winds and resulting turbulence expected in the area.
- The pilot lacked experience operating in such adverse meteorological conditions at this specific location.
- The aircraft's final resting position—vertical rather than horizontal—suggested the parachute was deployed at an altitude below the 2,000-foot threshold required for optimal stabilization.