Crash du Moswey III à Lägern-Hochwacht après des manœuvres à basse altitude

Le 29 mars 1959, un planeur Moswey Segelflugzeug-Werke Moswey III s'est écrasé à Lägern-Hochwacht, Suisse. Le pilote a effectué plusieurs manœuvres à basse altitude, entraînant une collision avec les cimes des arbres. Le planeur a été gravement endommagé, et le pilote a subi des blessures graves, entraînant une invalidité permanente. L'enquête a confirmé la perte de contrôle due au contact avec des obstacles au sol lors de vols à basse altitude non autorisés.

1. Aerotow to thermaling: The pilot aerotowed from Flugplatz Dällikon at 16:26 and released near the Lägern ridge, remaining in the area while flying with repeated high-speed dives and pull-ups.
2. Low-level maneuver habit: The pilot was known for somewhat doubtful discipline and had reportedly dived the Lägern-Hochwacht lookout to about 15 m on a previous day, indicating a pattern of risky low flying near this site.
3. Thermal weakening: Around 17:00 the thermals over the Lägern weakened, causing other gliders to leave the area and leaving the pilot alone while he continued maneuvering at low altitude.
4. Unauthorized low pass: Without external necessity the pilot began repeatedly diving steeply from 50–80 m above the Hochwacht signal and passing over the lookout at very low height and high speed while calling and waving to spectators.
5. Repeated low dives: He executed this low-level dive, low pass, and brusque pull-up maneuver twice, then initiated a third dive even lower, flying between the trig point and the barn’s lightning rod.
6. Tree-top strike: On the third low pass the glider, still at high speed and only slightly below the level of the signal, simultaneously struck the upper branches of the dense young forest with its wing and tail leading edges, causing an immediate loss of controllability.
7. Crash - serious injury: After striking the treetops the glider descended down the steep slope, breaking branches and small trunks until both wings and most of the tail were torn off and the fuselage came to rest steeply against a tree about 150 m below the lookout, leaving the pilot seriously injured and the aircraft destroyed.