Gas compressor startup procedures are complex and demand expertise. With over 50% of the workforce having less than five years of experience, an intensive 5-week training and 12-month mentorship are required. To bridge this gap, an AR-based immersive training tool with a real-time sequential startup checklist was developed. The Facility Operator Co-Pilot, powered by AVEVA PI DAHS and Aramco GenAI LLM, embeds live equipment data, process parameters, and system alerts into operator workflows. It enables faster, error-free startups, guided decision-making, anomaly detection, and improved reliability while mimicking control systems for just-in-time learning and enhanced operational excellence.