Welcome to HUMS Development

Health and Usage Monitoring Systems (HUMS) are used for rotor track and balance, exceedance monitoring, engine and drive train diagnostics, and structural UM. HUMS typically consists of a variety of onboard sensors, algorithms, and data acquisition systems. The acquired data may be processed onboard the rotorcraft or on a ground station (or a combination of both) providing the means to measure against defined criteria and generate instructions for the maintenance staff and/or flight crew for intervention. To meet these needs a variety of HUMS have been developed and put into service. Initially, these systems were installed to demonstrate the feasibility of gathering meaningful data to modify required maintenance and/or operational actions. The degree of qualification required for this type of installation is relatively low.

Driven by increasing demands for safety improvement and operational cost reduction, and the availability of new enabling technologies and science, advanced HUMS technologies and applications are emerging. The new technologies and applications present complex certification issues related to HUMS hardware and software certification, for both the airborne and ground based parts of the system. Additionally, potential use of HUMS to support evolving damage tolerance approaches to continued airworthiness pose many complex issues. This type of installation requires a higher degree of qualification, commensurate to the criticality of the most severe effect of the intervention action(s) on the rotorcraft. Additionally, as tools and methodologies for the rotorcraft damage tolerance (DT) have been significantly developed and our understanding of DT philosophy has been substantially improved, the combined DT and HUMS technologies to address safety must also be considered.

FAA Advisory Circular AC-29-2C, Section MG15, addresses airworthiness approval of HUMS. The AC provides guidance for achieving airworthiness approval for installation, credit validation, and instructions for continued airworthiness (ICA) for a full range of HUMS application. Installation includes all the equipment needed for the end-to-end application that is associated with acquiring, storing, processing, and displaying the HUMS application data, including airborne and ground-based equipment. Credit validation includes evidence of effectiveness for the developed algorithms, acceptance limits, trend setting data, tests, etc., and the demonstration methods employed. A plan is needed to ensure continued airworthiness of those parts that could change with time or usage and includes the methods used to ensure continued airworthiness. The AC establishes an acceptable means, but not the only means of certifying a rotorcraft HUMS.

Certification of HUMS addresses the complete system, including quality assurance of data produced from the airborne modules of the HUMS, and the potential subsequent intervening actions resulting from the ground processing of the airborne data. In summary, the main objectives of FAA HUMS R&D are: • Validation of certification procedures contained in AC-29-2C, Section MG-15, • Substantiation of HUMS applications used to support rotorcraft damage tolerance approaches for continued airworthiness issues, • Advancement and demonstration of sensor technologies, • Research and demonstration on the use of HUMS to provide on-board warning to flight crew, and • Flight testing with HUMS-installed helicopters.