This SAE Aerospace Information Report (AIR) is applicable to rotorcraft structural health monitoring (SHM) applications, both commercial and military, where end users are seeking guidance on the definition, development, integration, qualification, and certification of SHM technologies to achieve enhanced safety and reduced maintenance burden based on the lessons learned from existing Health and Usage Monitoring Systems (HUMS). While guidance on SHM business case analysis would be useful to the community, such guidance is beyond the scope of this AIR. For the purpose of this document, SHM is defined as “the process of acquiring and analyzing data from on-board sensors to evaluate the health of a structure.” The suite of on-board sensors could include any presently installed aircraft sensors as well as new sensors to be defined in the future. Interrogation of the sensors could be done onboard during flight or using ground support equipment. Finally, for the purpose of this document, it is assumed that the primary user of SHM in the near term will be the maintenance and operations crew, and this document will not include guidance on the many issues associated with displaying SHM data or recommendations to the flight crew in real-time.
•Establish lessons learned from the development, integration, qualification, certification, and deployment of rotorcraft HUMS functionality as they relates to SHM •Define key elements of rotorcraft SHM system functionality, including key similarities and differences compared to fixed wing SHM as defined in SAE ARP 6461, entitled “Guidelines for Implementation of Structural Health Monitoring on Fixed Wing Aircraft” •Provide guidance on the implementation of SHM in rotorcraft applications aligned with different application scenarios (e.g., temporary mitigation of fleet structural integrity issue, Condition Based Intervention (CBI) of proactive maintenance than published schedule, deferment or SHM triggering of traditional visual or NDI inspections or condition-based maintenance for fault-tolerant structures and maintenance practices) •Provide guidance on controlled introduction to service and validation of SHM efficacy through combined validation testing and fleet experience •Provide guidance on known regulatory requirements and approaches for obtaining SHM-based maintenance credits •Provide guidance on how SHM can be incorporated within or as modifications to current maintenance and airworthiness documents •Provide input for consideration by airworthiness authorities and regulatory agencies for refinement of guidance related to HUMS-based maintenance credits and Condition-Based Maintenance (CBM)