Kilchenstein, G. and Juarez, F., "Item Unique Identification Cost Benefit Study for Legacy Gas Turbine Engine Fleet Maintenance," SAE Technical Paper 2015-01-2486, 2015, doi:10.4271/2015-01-2486.
The USAF T56 engine Program Office has adopted a unique maintenance approach which utilizes the concept of complete system reliability in order to optimize their cost of workscoping aircraft gas turbine engines. While classical Reliability Centered Maintenance (RCM) focuses on the actual reliability and failure modes representative of a particular system, its benefits are limited since it only describes individual system components9. The workscope cost optimization program provides the user with recommended optimal repair workscopes based on the underlying reliability and cost of repair options. This maintenance concept is based upon the methodology documented in SAE Aerospace Recommended Practice (ARP) JA6097, which is a “Best Practices Guide” established to provide direction in objectively determining which other maintenance to perform on a system when that system requires corrective action, with the goal of improving overall system reliability at the lowest possible cost.The success of the program in improving T56 engine time-on-wing (TOW) is directly tied to the quantity and quality of data collected at all levels of maintenance and documented in various computer databases. Currently, information regarding component or engine reason for removal (RFR), among other data, is manually entered into these databases, which leads to occasional errors in time tracking and part information as well as many labor-hours expended at all levels of maintenance when errors are reconciled. Commercially-available reliability software tools are heavily reliant on these data collection systems for engine workscoping and predictions. Item Unique Identification (IUID) can enhance the quality and reduce to the costs of data collection by: 1- minimizing data entry error while simultaneously decreasing labor, 2- easing logistical tracking, 3- automating data processes, 4- utilizing controlled marking techniques, and 5- its ability to quickly customize and edit required data fields when necessary.Data collected during this demonstration indicated that IUID can reduce labor associated with data entry by approximately 86% at the T56 depot, which accounted for a significant amount of the total maintenance process. The result from analysis and this technology can also serve as a preventative measure to reduce manually-entered errors by approximately 25%, which have been observed in approximately a quarter of all engine data and information queries. IUID also proved to ease the addition of currently non-time tracked engine items into a database.The addition of other engine components into the USAF databases is expected to involve a significant amount of labor and complexity, but some non-time tracked components contribute notably to engine reliability and readiness. Therefore, the USAF is expected to benefit form incorporating these items into a maintenance workscope cost optimization program.The IUID demonstration evaluated a variety of IUID marking options that were non-detrimental to material surfaces. The return on investment (ROI) was also estimated to be achieved soon after implementation; therefore, providing significant cost savings to all stakeholders and reducing cost of ownership for the USAF or any user very rapidly.