The article reviews National Transportation Safety Board (NTSB) investigations into multiple Cessna 210 aircraft accidents caused by failed hydraulic actuators in the main landing gear systems. Investigators discovered a pattern of fatigue cracks in 7075-T6 aluminum actuator barrels that initiated at corrosion pits along the retaining ring groove, propagated under cyclic loading, and eventually resulted in circumferential and longitudinal fractures that leaked hydraulic fluid. Although these failures have not yet caused significant injuries, they present serious safety risks by impairing pilots' ability to fully extend and lock the landing gear. The article details the metallurgical examinations that revealed multiple crack initiation sites containing chlorine-rich aluminum oxide pits, some with cadmium remnants from the adjacent steel retainer ring, suggesting potential corrosion mechanisms. The researchers conclude that the combination of thin-walled design, stress concentrations at the retaining ring groove, susceptibility of the high-strength aluminum alloy to corrosion, and possibly inadequate inspection procedures all contributed to these premature failures, prompting ongoing work with the FAA to address the issue.

The hands-on experience provided during an Eisenman Materials Camp for students is a compelling way to excite young people to consider a STEM career. The volunteer-lead curriculum pairs a weeklong failure analysis project with many hands-on heat treating, metal casting, and materials characterization experiments. This article provides background about the Eisenman camp as well as the other student camps organized by the ASM Materials Education Foundation and discusses their benefits and long-term impact.