Novel internal sensors for helicopter main rotor gearboxes

Abstract

Since the 1980s, the use of onboard sensors for helicopter health and usage monitoring systems (HUMS) has been increasingly popular for benefits of enhanced safety. However, despite these successes, recent accidents, such as that to G-REDL, have raised questions about the efficacy and limitations of HUMS systems. This paper presents an overview of an EASA-funded project looking into the use of internal sensors in helicopter main rotor gearboxes for the improved detection of incipient damage. It details the process of: reviewing the failure modes; selecting a sensing technology; lab-scale testing of the sensor and wireless transmission; and implementation and successful full-scale testing of a prototype system.