What happened
On June 26, 2018, a Grob Astir CS Jeans glider, registration EC-LMB, was participating in a gliding competition at the La Cerdanya aerodrome. After approximately three hours of flight, the pilot encountered strong downdraft conditions while flying through the Andorra valley. Unable to find rising thermals to return to the departure airfield, the pilot decided to head south toward the Andorra-La Seu d’Urgell airport (LESU).
During the transit through the La Valira river valley, the aircraft lost significantly more altitude than anticipated. Upon reaching the vicinity of La Seu d’Urgell, the pilot determined there was insufficient altitude to reach the airport and identified a nearby agricultural field as a suitable landing site. During the final approach to this field, the aircraft entered a stall and struck the ground.
The investigation
The investigation examined the flight trajectory using GPS data and analyzed the aircraft's altimeter performance. It was established that the pilot had incorrectly set the altimeter at the start of the flight, resulting in an error where the altimeter indicated approximately 115 meters less than the actual altitude. This discrepancy, combined with the visual perception of the airport runway, led the pilot to believe they were too low to reach the official aerodrome.
Investigators also analyzed the flight path during the final approach to the field. The pilot performed a series of tight, zigzagging turns to manage the descent. The investigation focused on the aircraft's orientation relative to the wind and the aerodynamic state of the glider during the impact.
Findings
- The pilot performed an improper approach maneuver to the selected landing site.
- The approach sequence resulted in the aircraft transitioning from a headwind during the "downwind" leg to a tailwind during the "final" leg.
- The inadequate execution of the approach maneuver caused the aircraft to impact the ground with excessive speed.
- The aircraft struck the ground with the main landing gear while drifting diagonally, causing structural damage to the fuselage and the separation of the tail unit.
- The pilot was uninjured, though the aircraft sustained significant structural damage, including a broken fuselage and a detached rudder.