Weihe 50 incident near Froges: control loss leads to crash into trees
On April 29, 1962, a Weihe 50 glider, operated by the Aéro-Club de Bâle, experienced a control failure near Froges, France. While thermaling to regain altitude, the glider's rudder control cable broke, causing the pilot to lose control. The glider spiraled and collided with trees, resulting in significant damage. The pilot, the sole occupant, sustained a vertebral fracture but survived. The investigation noted a mechanical failure as the cause of the control loss.
- Cross-country thermaling: During a cross-country distance task from Sisseln toward Grenoble, the pilot was thermaling to regain altitude on the left side of the Isère valley after being driven down by strong sink.
- Low height near slope: The glider was orbiting close to a hillside at about 500 m above the Isère valley, leaving limited margin from terrain while thermaling.
- Rudder cable failure: While spiral climbing above the hamlet of Langelet, the left rudder control cable suddenly failed near the corresponding pedal, likely due to abnormally reduced mechanical strength.
- Loss of yaw control: The rudder failure caused loss of effective yaw control, and the glider continued in a wide right-hand turn that the pilot could not arrest, gradually converging toward the slope and trees.
- Crash - serious injury: Still in a right turn, the glider struck tree tops, broke apart, and crashed on a sloping field, seriously injuring the pilot and heavily damaging the aircraft.