Struktureller Ausfall der EoN Olympia 460 während Windenstart auf dem Flugplatz Sleighford

Am 13. Juli 1996 erlitt eine EoN Olympia 460 während eines Windenstarts auf dem Flugplatz Sleighford in Staffordshire einen tödlichen strukturellen Ausfall. Das Segelflugzeug, gesteuert von einem Piloten mit etwa 50 Flugstunden, erlitt kurz nach dem Start einen katastrophalen Flügelbruch. Zeugen beobachteten ungewöhnliche Nickschwingungen und Flügelverformungen, bevor der rechte Flügel versagte. Das Flugzeug wurde zerstört, und der Pilot überlebte nicht. Nachfolgende Untersuchungen ergaben erhebliche Korrosion im Flügelholm, die zum Versagen führte.

1. Winch launch climb: The glider began a winch launch from Sleighford Airfield, quickly becoming airborne and adopting the climb attitude in what witnesses considered a faster, less steep than normal launch.
2. Degraded wing spar: Long-term corrosion and bond failure in the right wing spar root alloy strap assemblies had significantly reduced the structural strength of the spar.
3. Over-strong weak link: The winch cable weak link assembly, using two identical 500 kg links in parallel, was found to fail at about 987 kg, allowing excessive launch loads to be transmitted to the airframe.
4. Excessive launch loading: During the winch climb at around 600–700 feet, the combination of a fast launch and over-strong weak link likely imposed loads that exceeded the degraded right wing spar’s strength.
5. Pitch oscillations and flex: While still on the cable in a nose-high attitude, the glider developed relatively rapid pitch oscillations and witnesses observed abnormal wing flexing.
6. Right wing structural failure: As the airbrakes briefly deployed and then deployed again, the right wing main spar failed, the wing pivoted upwards and rearwards with debris released, and the cable separated from the glider.
7. Crash - fatal: With the right wing failed at low altitude, the glider broke up and impacted the ground before the pilot could escape by parachute, fatally injuring the pilot and destroying the aircraft.