Abstract: The P-type clamp with gasket for the fixed cable of a certain aircraft has experienced multiple fractures during service. The cause of clamp fracture was studied using methods such as macroscopic observation, chemical composition analysis, scanning electron microscopy analysis, metallographic examination and finite element analysis. The results show that the clamp experienced a bidirectional bending fatigue fracture with multiple sources of cracking. The reason for the fracture was due to the cantilever installation of the clamp, which resulted in excessive stress on the surface of the clamp mounting foot and stress concentration. Under the repeated action of alternating stress, fatigue fracture occurred in the stress concentration area. Changing the installation method of the clamp to a snug fit installation, fatigue fracture of the clamp at the position could be avoided.