Propeller Failures in General Aviation Aircraft

Propellers used in experimental amateur-built aircraft make use of multiple material systems that balance strength, weight, and aesthetic. In 2023 and 2024, the National Transportation Safety Board examined propellers from three general aviation accident investigations in which one or more blades departed from the hub. The blades from each accident were manufactured with different material systems; carbon fiber composite, carbon fiber composite with an aluminum core, and wood. The presentation covers the circumstances of each accident and the laboratory examination of the blades. The microscopic examination techniques and the unique damage signatures from each material system are highlighted, alongside the similarities seen in each accident. Aspects of design, manufacturing, and maintenance practices in each accident are discussed.