Failure Analysis of Bearings of Aero-Engine

Failed bearings of various aero-engines were subjected to investigations. The bearing of cooling turbine of aircraft designated as B-1 was found to fail due primarily to misalignment and overloading. Bulk fatigue and permanent dimensional changes also accelerated the failure. The center main bearing of another aero-engine designated as CMB-1 was found nonfunctional because of 'Brinelling' action. Lack of lubrication caused over heat and deformation of rollers by metal to metal contact, and this resulted in formation of untempered martensite, leading to failure of center main bearings referred as CMB-2 of another helicopter engine. Stationary race and rotating race of thrust bearing of positive displacement reciprocating hydraulic pump bearing denoted as EDP-1 failed by abrasive action of foreign particles and oxidized metallic particles. In contrast, balls of the same bearing failed because of abrasive action of oxidized metal debris and rolling contact fatigue.