What happened
During a flight at Skövde airport, a GROB G 103 C "TWIN III" sailplane was performing a landing approach under favorable weather conditions, characterized by clear skies and light winds. The sequence of events began during the initial final approach when the pilot extended the aircraft's airbrakes excessively. This setting was maintained throughout the descent, causing the aircraft to lose altitude more rapidly than intended. To compensate for the high sink rate and maintain sufficient airspeed, the pilot lowered the aircraft's nose.
As the aircraft approached the runway, the pilot realized there was insufficient altitude to clear a group of small trees located on the approach path. This realization induced significant stress. In an attempt to correct the situation, the pilot inadvertently moved the airbrake lever in the wrong direction, which further increased the sink rate. Consequently, the right wing of the sailplane struck the trees during short final. The impact led to a hard landing on the nose wheel, followed by a sideways slide on the runway. The aircraft sustained substantial damage, though the pilot escaped without injury.
The investigation
The Swedish Accident Investigation Authority examined the pilot's actions and the mechanical operation of the airbrakes. The investigation established that the pilot could not provide a clear reason for the initial excessive extension and maintenance of the airbrake setting. Furthermore, the pilot noted that the physical handling of the airbrake lever did not align with the instructions received during his flight training.
Findings
- The primary cause of the accident was the incorrect use of the airbrakes during the approach phase.
- The pilot's stress, caused by the lack of altitude margin over obstacles, likely led to the error of operating the airbrake lever in the wrong direction.
- The improper airbrake setting caused an excessive descent rate, which necessitated a nose-down attitude to maintain airspeed, further reducing the margin for error.
- The collision with the trees induced a disturbance in yaw, which was the most likely factor leading to the hard nose-wheel landing and subsequent lateral slide.