The aircraft landing gear is a complex multi-degree of freedom dynamic system, and may encounter vibration or dynamic response problems induced by braking action. The vibratory modes can be induced by brake and tire-ground frictional characteristics, antiskid operation, brake design features, landing gear design features, and tire characteristics. The impact of this vibration can range from catastrophic failure of critical system components or entire landing gears, to fatigue of small components, to passenger annoyance. It is therefore important that the vibration is assessed during the design concept phase, and verified during the development and testing phases of the system hardware.
This SAE Aerospace Information Report (AIR) has been prepared by a panel of the A-5A Subcommittee to present an overview of the landing gear problems associated with aircraft braking system dynamics, and the approaches to the identification, diagnosis, and solution of these problems. All pertinent system modes of vibration are described. In addition, facilities and techniques available for test and evaluation are presented and discussed, and useful references are cited. The terminology used is intended to be consistent with AIR1489, “Aerospace Landing Gear Systems Terminology”, but some terminology herein is not yet included in AIR1489. The panel members include representatives from major brake, landing gear, aircraft, and brake control system manufacturers. In addition, drafts of the document were circulated for input beyond the SAE to other experts in the field.