Ka 4 Rhönlerche incident near Niedermuhlern during training flight
On May 12, 1963, an Alexander Schleicher Ka 4 Rhönlerche II was involved in an incident near Niedermuhlern, Switzerland. The glider, operated by a student pilot, was on a training flight from Bern/Längenberg airfield. The pilot encountered difficulties returning to the airfield due to altitude loss in strong winds. The aircraft descended into a wooded area, where it became entangled in trees. The pilot was uninjured, but the glider sustained significant damage to its wings.
- Training thermaling flight: Student pilot on a solo training flight departed Bern/Längenberg by aerotow for a planned 30–35 minute soaring flight in local thermals and hang lift.
- Drifted behind ridge: While using hang lift, the student allowed the glider to be carried about 5 km behind the Längenberg ridge line, contrary to the instruction to remain in the airfield zone.
- Low experience student: The pilot was a relatively inexperienced glider student with limited solo time and made optimistic tactical decisions about remaining in lift and returning.
- Headwind on return: On attempting to return toward Längenberg, the glider encountered headwind and general sink, causing rapid loss of altitude and making it increasingly doubtful that the airfield could be reached.
- Delayed outlanding decision: The pilot persisted in trying to get back toward the ridge and airfield, misjudging height and only deciding on an outlanding after descending to about 200 m above ground near Niedermuhlern.
- Low turn near obstacles: Approaching houses, a power line, and a small wooded depression, the pilot initiated a low-altitude avoiding turn at roughly 15–20 m above ground, during which the glider, likely already near the stall, sank further and the left wing struck tree tops.
- Outlanding - damage: The glider descended into a small wooded area and came to rest hanging in the trees with both wings heavily damaged, while the pilot remained uninjured.