Collision du Standard Cirrus avec une ligne électrique lors d'un atterrissage en campagne à Möriken, Suisse

Le 5 juin 1976, un Schempp-Hirth Standard Cirrus a heurté une ligne électrique lors d'une tentative d'atterrissage en campagne à Möriken, Suisse. Le pilote, participant à une compétition régionale, a rencontré une masse d'air descendant inattendue et n'a pas pu retourner à l'aérodrome de Birrfeld. En tentant de se poser dans un champ, le planeur a percuté une ligne électrique de 380 volts et s'est écrasé dans un jardin. L'appareil a subi des dommages importants, mais le pilote est resté indemne. L'enquête a souligné la prise de décision tardive du pilote comme un facteur contributif.

1. Aerotow cross-country: The pilot launched by aerotow from Birrfeld for a regional competition flight and proceeded on cross-country in the Standard Cirrus HB-1269.
2. Encounter strong sink: On the return leg from the Gisliflue toward Birrfeld, the pilot encountered unexpectedly strong sinking air and realized he could no longer reach the home airfield.
3. Lee-side sink unanticipated: The pilot paid insufficient attention to the Bise wind conditions and did not anticipate the significant downdrafts in the lee of the Chestenberg near Möriken and Brunegg.
4. Delayed outlanding decision: Despite inadequate height and the availability of several suitable outlanding fields between Gisliflue and Birrfeld, the pilot repeatedly postponed the decision to commit to an outlanding.
5. Aim for distant field: Believing he could still safely reach a known landing field near Brunegg, the pilot continued toward it instead of selecting a closer field.
6. Low-altitude field change: Arriving over Möriken at about 100 m above ground and realizing he could not reach the intended field, the pilot decided too late to land on a nearer meadow and flew a series of tight left turns toward it.
7. Crash - no injury: During the first 90° left turn the glider’s left inner wing struck a 380 V power line, causing a half rotation and tail-first crash into a garden between houses, heavily damaging the aircraft but leaving the pilot uninjured.