What happened
On March 7, 2004, a Twin Astir I glider, registration EC-EPU, departed from Monflorite Aerodrome in Huesca for a private recreational flight. The flight proceeded toward the Monte Aragón Castle area, utilizing wave lift conditions near the Guara mountains. After approximately one hour of flight, the pilot decided to return to the aerodrome, initiating a descent toward runway 3/1.
At the time of the landing, meteorological conditions featured good visibility but included strong winds. While winds above 1,000 meters were from the north, winds below 1,000 meters were blowing from the North-Northwest at approximately 21.7 knots. As the aircraft approached the runway, the pilot attempted to compensate for the crosswind component by using the rudder to crab into the wind. During the initial meters of the landing roll, the left wingtip made contact with the ground. This contact caused the aircraft to skid to the left, eventually coming to a halt on the runway facing the opposite direction of the initial landing heading. The aircraft sustained significant damage, including a misaligned landing gear, a broken cockpit, and longitudinal cracks in the fuselage. Both the pilot and the passenger were uninjured.
The investigation
The investigation focused on the pilot's maneuvers during the crosswind approach and the aerodynamic impact of the wing strike. The investigation established that the wind conditions were consistent with a strong North-Northwest component during the landing phase. The analysis examined the pilot's specific technique, which involved using the rudder to crab the aircraft toward the wind without significant aileron input, intending to use the rudder again to realign with the runway centerline upon touchdown.
Findings
- The primary cause of the incident was uncoordinated control inputs during the landing phase under crosswind conditions.
- The pilot's technique involved attempting to crab the aircraft using the rudder while lacking sufficient aileron input to manage the wind component.
- The contact of the left wingtip with the ground acted as a pivot point, which decisively contributed to the aircraft'skidding to the left during the landing roll.