Crash d'un LS 3 près de St-Imier dans des conditions turbulentes entraîne un décès
Le 14 juin 1992, un Rolladen-Schneider LS 3 s'est écrasé près de St-Imier, en Suisse, lors d'un vol d'entraînement local. Le planeur, piloté par son propriétaire, aurait perdu le contrôle dans des conditions turbulentes et a été retrouvé détruit dans une zone boisée. Le pilote n'a pas survécu à l'impact. L'enquête n'a pas pu déterminer les raisons spécifiques de la perte de contrôle, mais a noté des conditions de vent difficiles au moment de l'accident.
- Local soaring flight: After an aerotow launch from Courtelary and release near Tramelan, the pilot continued a local soaring flight in turbulent bise conditions in the St-Imier valley area.
- Turbulent bise winds: A bise wind regime over the Jura created locally turbulent and gusty conditions with abrupt changes in wind intensity near the terrain.
- Aft CG limit: The glider’s mass was within limits but the center of gravity was at the aft limit, making the aircraft more sensitive in pitch and potentially in stall and spin behavior.
- Low-altitude turn in sink: While apparently unable to find sufficient lift and flying low in the St-Imier valley, the pilot initiated a right turn, likely to interrupt the flight or reposition, at a height where margins were limited.
- Uncontrolled spiral: A witness saw the glider suddenly roll around its longitudinal axis until the full wingspan was visible and then enter a tight, descending turn, consistent with an inadvertent spiral or spin entry.
- Rudder input applied: Autopsy evidence of a hard left rudder pedal input indicates the pilot attempted to counter the rotation, but had insufficient height to complete a recovery.
- Crash - fatal: Still in a rotating descent, the glider struck treetops, inverted, and impacted the bottom of a wooded ravine, destroying the aircraft and fatally injuring the pilot.