Incidente de Ka 4 Rhönlerche II durante remolque aéreo en el aeródromo de Birrfeld, Suiza
El 9 de agosto de 1968, un Ka 4 Rhönlerche II experimentó un incidente en el aeródromo de Birrfeld en Suiza. Poco después del despegue, el avión remolcador sufrió una falla de motor debido al agotamiento del combustible, lo que requirió un aterrizaje en campo seguro. El planeador, pilotado por un estudiante, intentó regresar al aeródromo pero se estrelló durante una maniobra a baja altura. El piloto estudiante resultó ileso, pero el planeador sufrió daños. La investigación confirmó que la falla del motor se debió al agotamiento del combustible.
- Aerotow initial climb: During an aerotow departure from Birrfeld, the glider was climbing behind the tow plane at about 50 m above ground in a slight left turn.
- Towplane engine failure: The tow plane’s engine suddenly stopped due to fuel exhaustion, forcing an immediate termination of the tow at low altitude.
- Low student experience: The glider was flown solo by a relatively inexperienced student with only eight prior solo flights and limited total gliding time.
- Turn back toward field: After release, the student turned about 200° left intending to return to the airfield, then decided instead to land parallel to the nearby road when it became clear the road could not be safely overflown.
- Tightened low-altitude turn: With insufficient height remaining for a normal turn, the student pulled back on the stick while applying right rudder to tighten the final turn toward the intended landing direction.
- Stall and spin entry: The glider was over‑controlled into a low-speed, uncoordinated condition, entered a stall with spin tendency, and dropped out of the turn from about 5 m above ground.
- Crash - no injury: The glider impacted the field and was substantially damaged, but the student pilot was uninjured.