What happened
On January 1, 2023, at approximately 12:03 UTC, an amateur-built Corby CJ-1 Starlet, registration OK-AUV 91, crashed at Hodkovice nad Mohelkou airport (LKHD) in the Czech Republic. The pilot, who was using the aircraft to familiarize himself with its handling characteristics, was performing a series of maneuvers and approaches to runway 01.
As the aircraft approached the runway centerline in a slight descent, the pilot increased the left bank angle to align with the runway. During this maneuver, the structural integrity of the left wing failed. The failure occurred approximately three-quarters of the way along the wing, specifically near rib number 4. The loss of the wing caused the aircraft to enter an immediate, uncontrolled roll and descent. The aircraft struck the ground at a steep angle, causing the engine to separate and the fuselage to disintegrably break apart. The pilot sustained fatal injuries during the impact.
The investigation
The ÚZPLN investigation utilized several sources of evidence, including video footage from two airport security cameras, eyewitness testimony from experienced pilots, and official police records. The investigators also examined the aircraft's original construction plans and LAA ČR (Light Aircraft Association of the Czech Republic) documentation.
Technical analysis of the wreckage revealed that the main spar, a continuous I-beam construction made of glued wooden beams, had failed. The fracture pattern at the end of the main spar and rib 4 indicated that the wing tip had been subjected to extreme torsional (twisting) loads. The investigation also confirmed that the pilot was medically fit and properly qualified, though he was relatively inexperienced with this specific aircraft type.
Findings
- The primary cause of the accident was the probable exceedance of the maximum permissible speed (VNE) during the approach. The aircraft was likely traveling faster than the certified 200 km/h limit.
- The high-speed approach, combined with the increased left bank angle, generated aerodynamic loads that exceeded the structural limits of the wing's main spar and rib 4.
- The aircraft was an amateur-built, single-seat wooden construction, which is highly sensitive to aerodynamic overstress.
- While the pilot was qualified and the aircraft had a valid certificate of airworthiness, the aircraft lacked valid legal insurance at the time of the accident.