© 2021 Elsevier LtdThe main concern in aircraft structures is flight safety. One of the constraints to consider when designing safe aircraft parts is weight. The design of the landing gear structures is difficult because it must ensure flight safety without adding excessive weight. During takeoff, the main landing gear of a cargo plane did not retract. The landing procedure went off without a hitch. The maintenance crew disassembled and inspected the main landing gear to determine the source of the problem. The main landing gear cylinder support was discovered to be in broken condition. The part was broken at the 90-degree corner region. The location of the fracture is subjected to high stresses in service conditions especially during braking with a heavily loaded aircraft. Detailed destructive and, non-destructive evaluation procedures were applied to reveal the root cause or causes of the failure. The determination of the root cause is crucial to prevent a similar failure in the future. Visual inspection, electrical conductivity test, fractography, microstructural evaluation, chemical analysis, hardness test were applied to the part. After examination, it was determined that the support had failed due to fatigue. The conditions of use, low radius geometry in the crack origin, rough machined surface, and pitting corrosion all played a role in the failure.