Failure Analysis of Planetary Gear in a Geared Rotary Actuator Used in Aircraft Flight Control System

This paper reports the results of an investigation into the premature failure of planetary gear in a Geared Rotary Actuator used in aircraft flight control system. The gear failed about 2,000 h of service which was much shorter than the normal service life of 30,000 h. The failure of planetary gear was analyzed by scanning electron microscopy, spectrometer, hardness tester, metallographic microscope through macroscopic and microscopy examination of the fracture, microscopic analysis of the fracture, chemical composition analysis, hardness and microstructure examination. The results show that the chemical composition, hardness and microstructure meet the technical requirements of the material properties, but the plastic deformation of the fracture was obvious. The failure reason was the overload failure.