Experience with Health and Usage Monitoring Systems in Helicopters

Abstract

Advisory Circular 29-2 C, Section MG-15, Airworthiness Approval of Rotorcraft Health and Usage Monitoring System (HUMS), provides guidance for achieving airworthiness approval for installation, credit validation, and instructions for continued airworthiness for a full range of HUMS applications. The state-of-the-art HUMS and recent advancements including usage monitoring, flight regime recognition, fault, and crack detection technologies have begun to allow the use of HUMS for the condition-based maintenance or maintenance credits. “Maintenance credit” means to give approval to a HUMS application that adds to, replaces, or intervenes in industry-accepted maintenance practices or flight operations. Additionally, the future use of HUMS can eventually allow the fatigue life of rotorcraft components to be extended or the life-limited components to be removed before its fatigue life is fully consumed. Therefore, HUMS technologies and their applications can be used to achieve the safety goal, maintain continued airworthiness, and improve operating costs of rotorcraft. This article provides the Federal Aviation Administration (FAA) perspective of how HUMS are being used or may be used in rotorcraft to address safety and continued airworthiness issues. This article also describes a few FAA-critical research efforts to achieve the full implementation of HUMS for usage credits.