What happened
On June 18, 2020, a Diamond Aircraft DV 20 Katana, registered HB-SCL, was conducting training maneuvers at Grenchen Regional Airport. The flight, operated by Fliegerschule Birrfender AG, began with a flight from Birrfeld to Grenchen. Following several successful landings in dual instruction, the instructor decided to allow the student pilot to perform solo landings.
After a successful first solo attempt, the student pilot attempted a second landing on runway 24. During this second approach, the aircraft drifted left of the centerline and exited the runway perimeter, resulting in the destruction of a runway light and its mounting. The aircraft came to a stop a few meters from the runway. The student pilot was uninjured, though the incident was classified as a serious occurrence. No damage was found to the aircraft itself, aside from a minor scratch on the right main landing gear wheel pant.
The investigation
Investigators examined the environmental conditions and the pilot's actions during the landing phase. At the time of the initial dual landings, winds were light from the south. However, during the solo landing period, the wind shifted to the northwest and increased in strength, with gusts reaching approximately 27.7 km/h.
Physical evidence, specifically brake marks on runway 24, indicated that the left wheel brake was applied during touchdown. The student pilot acknowledged that this action was unintentional. The investigation found no evidence of mechanical or technical failures that could have contributed to the excursion.
Findings
- The primary cause of the excursion was the unintentional application of the left wheel brake by the student pilot while attempting to correct for a crosswind.
- A significant shift in wind direction and an increase in gust intensity occurred between the first and second solo landings, requiring different rudder corrections.
- The student pilot successfully managed the first solo landing despite the changing wind, but failed to maintain control during the second attempt due to the inadvertent braking.