What happened
On September 21, 2019, a Schempp-Hirth Discus 2CT glider, registration OY-KBX, was performing a solo flight at Gørløse (EKGL) under visual flight rules. During the flight, the pilot was being towed to a height of approximately 400 feet. After releasing from the tow plane on the upwind leg, the pilot perceived that the glider was flying too close to the tow aircraft. In response, the pilot deployed the airbrakes, experiencing a sensation that the aircraft's 'curtains were being pulled down.'
While turning onto the base leg, the pilot did not retract the airbrakes. As the aircraft transitioned to the final approach, the pilot realized the glider lacked sufficient glide ratio to reach the runway. The aircraft subsequently struck a tall bush, entered a ground loop, and crashed approximately 240 meters before the threshold of runway 2 and caused substantial damage to the aircraft, including separation of the tail boom and horizontal stabilizer.
The investigation
The investigation by AIB Denmark examined the aircraft's technical condition, weather, and the pilot's medical history. The investigation established that the weather conditions were clear with good visibility and that the aircraft was mechanically sound.
A critical focus was placed on the pilot's medical status. Prior to the accident, the pilot had undergone medical examinations that identified Mild Cognitive Impairment (MCI) and the onset of Alzheimer's disease. Although the pilot had informed their aero-medical examiner (AME) of these findings and provided copies of the medical reports, the AME had not suspended the pilot's medical certificate pending further investigation or a formal fitness assessment. The investigation noted that while the pilot had not previously experienced loss of situational awareness, the medical findings were known to the AME.
Findings
- The pilot's decision to deploy the airbrakes was likely triggered by stress during the flight, compounded by the physiological effects of Mild Cognitive Impairment (MCI) and early-stage Alzheimer's disease.
- The pilot failed to retract the airbrakes during the base leg, leading to an insufficient glide path for a safe landing.
- The aero-medical examiner's decision to allow the pilot to continue flying while the medical status remained unresolved was considered a high-risk action.
- At the time of the accident, there were no specific Danish regulatory guidelines regarding the management of neurological conditions like MCI for LAPL holders, though international guidelines (such as those from the UK CAA) suggested that such conditions represent a significant flight safety risk.