Incident de Ka 4 Rhönlerche II lors d'un entraînement à l'aérodrome d'Amlikon avec atterrissage dur

Le 19 août 1964, un vol d'entraînement impliquant un Alexander Schleicher Ka 4 Rhönlerche II s'est terminé par un atterrissage dur à l'aérodrome d'Amlikon, en Suisse. Le planeur a brusquement viré à droite lors de l'approche finale après avoir récupéré d'un glissement à gauche. Le pilote, un élève, a tenté de corriger la trajectoire mais a perdu le contrôle, entraînant un impact violent avec le sol. L'appareil a subi des dommages importants, tandis que le pilote a subi des blessures légères. L'incident s'est produit dans des conditions météorologiques turbulentes lors d'un cours de formation pré-vol.

1. Aerotow landing approach: During an aerotow training flight, the student pilot was on final approach to runway 28, executing a planned left glissade (slip) for landing.
2. Loss of coordination: After recovering from the left glissade at about 30 m AGL and slightly left of the centerline, the student failed to properly coordinate aileron and rudder inputs.
3. Low experience, turbulence: The pilot was a relatively low-time student and the approach sector was known to be turbulent in the prevailing west–southwest wind, potentially complicating control near the ground.
4. Right yaw and sideslip: The glider’s nose yawed sharply to the right while maintaining bank, departing the runway heading at roughly a right angle in a strong sideslip and crossing over the Thur in downwind.
5. Attempted right turn back: Per the investigator’s assessment, the student likely attempted to turn the unintended right yaw into a deliberate right turn to bring the glider back toward the airfield, but did not regain effective control.
6. Unarrested descending turn: The glider continued in a descending right turn with 20–30° nose-down attitude and bank, with no visible flare or reduction of bank before ground contact.
7. Crash - minor injury: Still in a right turn and nose-low attitude, the glider impacted the ground hard near the beginning of the runway, breaking the right wing and deforming the fuselage, and the pilot sustained minor facial injuries.