Some terrible disasters of aircrafts were caused by inadequate lubrication or interruption of lubricant delivery of the gas turbine engine mainshaft bearings. This paper introduces the design of the test equipment, performs the experiments of failure performance for 51306 coated bearings to respond to oil interruption under the actual situation. The main failure performance of test coated bearings has been demonstrated to be the cage damage of the test coated bearing. The failure mechanism model of the damaged cage of test coated bearings under oil interruption condition is established for the failure analysis of damage cages. The failure mechanism of the damaged cages is revealed. The main reason for the damages of test coated bearing cages under lubricant interruption condition is that the perpendicular component force acted on the cage increases continually to go with the increase of the friction force between the balls and the cage due to inadequate lubrication until the cage is broken.