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Availability of large repairable systems, like aircraft, are critical for commercial operators to generate revenue, and for military organizations to achieve their mission readiness objectives. Of the relatively few studies that deal with improving availability, most have focused on increasing reliability, and not on the biggest driver of low availability - Unscheduled Maintenance Events (UMEs). The cost of maintenance has long been a target of cost-cutting measures, and one common strategy focuses on extracting as much service life as possible out of various non-critical system components by letting those components “run to failure” (as defined in SAE JA1012). However, one of the biggest drawbacks of the “run to failure” approach is that it comes at the cost of lower asset availability because the failure of one of those components will nearly always lead to a UME, typically just when the operator wants to use, or is currently using, that asset.

This paper presents the methodology for performance optimization of different active power converters (active front-ends, isolated DC/DC converters and three-phase isolated converters) for aircraft applications. ...In modern aircraft power systems, active power converters are promising replacements for transformer rectifier units concerning efficiency and weight. ...To assess the benefits of active power converters, converter design and optimization should be carefully done under the operation requirements of aircraft applications: electromagnetic interference (EMI) standards, power quality standards, etc.

The Vapor Phase Catalytic Ammonia Removal (VPCAR) Technology has undergone long duration testing at MSFC. The results of this testing revealed several areas in which the VPCAR Technology could be improved and those improvements are summarized here.

The testing method is the active thermography. The active thermography has major advantages compared with other non-destructive testing methods. ...In this variant of testing with active thermography, the positioning time for the measurement system is eliminated and by spatial shifting the contrast of failure measurement, a much shorter testing time will be achieved.

Ideally, air quality can be maintained by striking a proper balance between the generation and removal of contaminants. Both very dynamic processes, the balance between generation and removal can be difficult to maintain and control because the state of the cabin atmosphere is in constant evolution responding to different perturbations. ...Typically, maintaining a clean cabin environment on board crewed spacecraft and space habitats is a central function of the environmental control and life support (ECLS) system. While active air quality control equipment is deployed on board every vehicle to remove carbon dioxide, water vapor, and trace chemical components from the cabin atmosphere, perturbations associated with logistics, vehicle construction and maintenance, and ECLS system configuration influence the resulting cabin atmospheric quality.

The maintainability and reliability data collected will provide information from product removal through depot overhaul/repair analysis and resultant verification of removal cause. The disassembly and analysis for removal cause will assist in determining if enhanced maintainability training, corrective action, or modification for the products is required. ...The disassembly and analysis for removal cause will assist in determining if enhanced maintainability training, corrective action, or modification for the products is required.