What happened
On April 27, 1968, a Ka 8B glider, registration HB-668, was conducting a training flight at the Olten airfield. The pilot, who had recently resumed flight training after an eighteen-month hiatus, had performed two supervised control flights earlier that day before receiving permission to fly the aircraft solo.
After being towed to an altitude of approximately 1,100 meters, the pilot released from the tow rope near Aarburg. During the return flight to Olten, the pilot encountered significant headwinds. While approaching the airfield, the pilot executed a 180-degree turn to set up a landing pattern consisting of two 90-degree turns. However, due to the prevailing southwest wind, the aircraft's ground speed was significantly reduced, causing the final approach to fall short of the runway. In an attempt to land on the edge of a gravel pit located roughly 110 to 120 meters before the start of the runway, the aircraft's wing struck the ground during a left turn, resulting in a crash landing on the slope of the pit. There were no injuries to the pilot, though the aircraft sustained substantial damage.
The investigation
The investigation examined the flight conditions, the pilot's recent training history, and the airfield terrain. It was noted that the airfield at Olten featured a grass runway and was situated near a deep gravel pit. The investigation also reviewed the pilot's experience, noting that while the pilot held a valid license, they had only approximately 40 hours of total flight training and were in the process of re-establishing flight proficiency.
Findings
- The primary cause of the accident was the pilot's failure to properly account for the prevailing wind conditions during the approach.
- The pilot underestimated the impact of the southwest wind on the aircraft's ground speed, leading to an undershoot of the runway.
- The pilot's decision-making regarding the approach pattern did not sufficiently consider the extra altitude required to overcome the headwind component on the final leg.