Lubricant Condition Assessment System (LUCAS), an Enabler for Condition Based Maintenance Best Practice

This paper discusses a lubrication monitoring system developed under an Army program called the Lubricant Condition and Assessment System (LUCAS). LUCAS is a smart embedded monitoring device to provide aerospace gearboxes and engines with an on-line sensing solution for both the characterization of lubricant condition/contaminants as well as the detection of ferrous/non-ferrous wear metals generated by the mechanical systems as they experience wear out damage. The oil condition measurement interrogates the oil broadband impedance to detect and classify lubrication quality factors (related to oil chemistry change) such as incorrect oil addition, moderate to high water content, oil oxidation degradation, and additive depletion among other issues. A separate sensing system, using an inductive coil design, classifies both ferrous and non-ferrous debris down to nearly 40 micron size. This size particle is considered more than adequate to detect incipient abnormal wear in the gear, bearings, and other components. These measurements and diagnostic assessments are available onboard on a continuous, real-time basis and the data can be directly integrated into the aircraft's digital source collector (DSC) to determine overall lubricant's health and indicate when components in the lubricants path are becoming compromised. Such information will be very useful when implementing condition based maintenance (CBM/CBM+) practices. This paper will discuss the Army's current methodology of lubricant monitoring, design features of the LUCAS, testing results to date, and finally the path forward for LUCAS devices in Army aviation.