What happened
On September 11, 2023, an Aerospool WT9 Dynamic ultralight aircraft departed from the Walldürn airfield for a flight to Hof-Plauen. Shortly after takeoff from runway 06, the aircraft entered an uncontrolled flight state. Witnesses observed the aircraft transition from a shallow climb into a parabolic flight path before descending steeply. The aircraft subsequently veered to the right and impacted a harvested field near Höpflingen.
The pilot sustained fatal injuries in the crash, and the aircraft was destroyed. The impact caused damage to the surrounding field.
The investigation
The BFU examined the wreckage and the cockpit canopy. Investigators found that the right side of the canopy had broken away from its front hinge, and the left side had detached from its guide bush. The right canopy stop bolt had been torn from the canopy frame. The investigation also reviewed the aircraft's maintenance history, noting that a 100-hour inspection had been completed approximately two months prior to the accident.
Additionally, the investigation considered historical safety data regarding the Aerospool WT9 Dynamic. Previous safety notices from the German Aero Club and airworthiness directives from Austro Control had highlighted risks associated with the canopy latching mechanism, specifically the potential for the canopy to open spontaneously in flight if not properly secured.
Findings
- The aircraft entered an uncontrolled flight regime during the initial climb.
- The cockpit canopy failed, with the right side breaking from its hinge and the stop bolt being torn from the frame.
- The spontaneous opening of the canopy significantly disrupted the aircraft's stability and controllability.