Incident du Ka 4 Rhönlerche II lors d'un atterrissage d'entraînement à l'aérodrome d'Amlikon
Le 7 avril 1972, un élève-pilote aux commandes d'un Alexander Schleicher Ka 4 Rhönlerche II a rencontré des difficultés lors d'un vol d'entraînement à l'aérodrome d'Amlikon en Suisse. Lors de l'approche d'atterrissage, le pilote a effectué un dérapage latéral à droite mais a eu du mal à coordonner les commandes en redressant. L'appareil a dévié de sa trajectoire et a atterri sur un chemin voisin, où une extrémité d'aile a heurté un buisson. Le planeur a subi des dommages importants, mais le pilote est resté indemne. L'enquête a attribué l'incident à une utilisation incorrecte du gouvernail pendant la manœuvre d'atterrissage.
- Winch launch training: During a training flight at Amlikon, the student pilot completed a winch launch and began circuit flying for his 14th solo.
- Low pilot experience: The student pilot had a total of 7 hours 47 minutes on type and was known to have occasional difficulty coordinating controls when recovering from a sideslip.
- Landing approach setup: From about 200 m AGL the pilot flew a normal landing pattern, fully extended the airbrakes, and initiated a right sideslip on final.
- Rudder misused in recovery: While recovering from the right sideslip just above the ground, the pilot applied full right rudder instead of coordinating the controls correctly.
- Glider yaws off course: As the aircraft was brought out of the sideslip, it yawed and turned to the right, ending up flying about 45 degrees across the intended landing direction over the river Thur at roughly 80 km/h.
- Decision to land on path: Seeing the glider misaligned and over the river, the pilot elected to land on the track along the right riverbank embankment.
- Outlanding - damage: During the rollout on the embankment track the left wing struck a bush, causing the glider to slew left and sustain serious damage while the pilot remained uninjured.