Pilatus B4 crash during training flight near Ulrichen, Switzerland
On July 29, 1987, a Pilatus B4-PC11AF was involved in a crash near Ulrichen, Switzerland during a training flight. The pilot, who was flying solo as part of an alpine gliding camp, released the tow cable at an insufficient altitude of 2100 meters. Despite realizing the error, the pilot continued the flight to avoid returning to Münster due to scheduling constraints. The glider stalled during a turn and collided with a steep slope. The pilot sustained serious injuries, and the aircraft was destroyed.
- Aerotow to ridge: During an alpine gliding camp, the pilot departed Münster in aerotow in a Pilatus B4 for a solo training flight along the Goms valley.
- Premature tow release: After a 180° turn near the Oberwaldergrimsel/Chietal area, the pilot released from tow at about 2100 m MSL, already below local ridge height contrary to prior instruction.
- Desire to avoid landing: Realizing she had released too low, the pilot nevertheless decided to continue the flight to avoid an early landing at Münster that would prevent another launch due to reservations.
- Low, slow ridge flying: In pure thermal conditions and with shallow local slopes, the pilot flew slow figure‑eight patterns close to the hillside, reducing height margin for corrections.
- Poor speed monitoring: The pilot flew mainly by feel and paid little attention to the airspeed indicator while maneuvering near the slope.
- Stall and loss of control: During a turn toward the valley at low height, the glider dropped below minimum flying speed, stopped responding properly to control inputs, and departed controlled flight.
- Crash - serious injury: The glider impacted a steep slope near Flieli, 1.5 km northwest of Ulrichen, seriously injuring the pilot and destroying the aircraft.