Ka 4 Rhönlerche II stall after winch launch failure at Swiss military airfield
On March 21, 1964, an Alexander Schleicher Ka 4 Rhönlerche II experienced a winch launch failure at a military airfield in Switzerland. The glider, piloted by a flight instructor and a student, suffered a cable break during the ascent. Despite the availability of a long runway ahead, the instructor attempted a turn back to the start point. The glider stalled and spun from approximately 15-20 meters, impacting the runway. Both occupants were uninjured, but the aircraft sustained damage to its left wing and nose.
- Winch launch climb: During a dual-instruction winch launch from a military airfield, the Rhönlerche began its initial climb with the student in front and the instructor in the rear seat.
- Cable break in climb: After the glider had covered about 200–300 m and reached roughly 50–60 m height, the winch cable’s weak link failed and the cable broke.
- Adequate landing area ahead: Despite approximately 800 m of hard-surface runway and a further 1000 m of flat grass available straight ahead, the crew did not plan for a straight-ahead landing after the cable break.
- Student recovers, proposes turn: The student correctly lowered the nose to stabilize the glider after the cable break and then proposed a turn back toward the launch point, which the instructor accepted.
- Instructor steepens low turn: When the student initiated a left turn that seemed too shallow, the instructor took over and increased the bank angle without increasing airspeed at low altitude.
- Stall and wing drop: After about 100–120° of heading change, the glider became too slow and stalled, dropping over the left wing from an estimated 15–20 m height.
- Crash - no injury: The glider struck the hard runway first with the left wingtip and then the nose, sustaining damage to the left wing and forward fuselage, while both occupants remained uninjured.