The purpose of this report is to outline types of in-service heat damage that have been observed in high strength steel landing gear components, with an emphasis on a particular type that is referred to as “Ladder Cracking” which can develop in landing gear shock struts. The report discusses how ladder cracking can be detected visually and evaluated by non-destructive inspection methods, and how it can be repaired at overhaul with the prior approval of the Original Equipment Manufacturer. This report also describes the use of a bearing material that has resolved this problem without introducing other problems. Examples of other types of service induced heat damage are also discussed.
This document is being revised to expand the discussion about service induced heat damage on high strength steel landing gear components beyond the shock strut inner cylinder sliding surfaces. This revision includes examples of heat damage on outer cylinders, inner cylinder pivot bores, and truck pivot pins. Also included is more information about inspection methods and repair procedures to address heat damage at overhaul.