Accidente del L-13 Blanik en Muottas Muragl tras pérdida de sustentación en condiciones turbulentas

El 2 de agosto de 1974, un Aero Vodochody L-13 Blanik se estrelló en Muottas Muragl, Suiza, durante un vuelo de entrenamiento. El planeador, pilotado por dos pilotos experimentados, entró en pérdida de sustentación después de que no se mantuviera la velocidad mínima de vuelo cerca de la cresta. Se reportaron condiciones turbulentas en el área, lo que pudo haber contribuido al incidente. El accidente resultó en la muerte del piloto en el asiento delantero y heridas graves al piloto en el asiento trasero. La aeronave fue destruida al impactar.

1. Ridge training flight: During a dual training flight after a winch launch from Samedan, the Blanik was flown in ridge lift along the Muottas Muragl slope at low height.
2. Very low ridge height: Witnesses observed the glider flying along the Muottas Muragl slope in very low proximity to the terrain, estimated around 20–30 m above ground.
3. Turbulent wind conditions: The accident area lay near the upper boundary of the Malojawind with known wind shear and strong turbulence, later confirmed by a helicopter pilot who experienced severe turbulence on approach to the site.
4. Speed near minimum: In the weak ridge lift the front-seat pilot tended to fly slowly, around the speed for minimum sink (about 68–80 km/h), close to the aircraft’s stall speed, prompting the instructor to call for more speed several times.
5. Minimum speed exceeded: While flying close to the slope in turbulent air, the glider’s airspeed dropped below the minimum safe flying speed, leading to an aerodynamic stall.
6. Abrupt nose drop: The Blanik suddenly pitched nose-down and entered a steep, near-vertical descent, described by witnesses as a vertical fall or vertical right spin toward the slope.
7. Crash - fatal: At about 14:36 local time the glider impacted the Muottas Muragl slope in a steep nose-down attitude and was destroyed, killing the front-seat pilot and seriously injuring the rear-seat pilot.