Developed and installed a predictive and preventative maintenance expert system (PPMES) on depot critical infrastructure that captures live sensor data; logs and transforms analog data into digital form using new wavelet theory; performs diagnostics and predictive tests to project failure potential; schedules maintenance; and organizes data for reliability, availability, and maintainability analysis and the establishment of spares management policies. PPMES minimizes breakdowns and defects, maximizes equipment operations rates, reduce life-cycle costs, extend equipment life, improve troubleshooting, and minimize spare and replacement parts inventory.