Seal failure mode and effects analysis for retractable actuator of landing gear

The piston seal elements of hydraulic actuating cylinder are easy to be abrasion and vulnerable on the occasion of abominable conditions, especially in the area of aeronautical application. This paper is focus on a safety accident causes by fault of nose landing gear actuating cylinder, analyzing the possible effects on actuating cylinder's function and performance after secondary seal ring failure and giving the corresponding conclusions that this failure won't lead the down-lock failure, but it is a hidden trouble in cylinder and its structure design must be improved.