A Boeing 777 is designed to fly for several hours on a single engine thanks to its ETOPS (Extended-range Twin-engine Operational Performance Standards) certification. Most modern 777 models, such as the 777-300ER, are certified for ETOPS-330, which means the aircraft is legally and technically capable of flying for 330 minutes (5.5 hours) on only one engine. This allows the plane to fly over vast oceans or remote polar regions where the nearest "diversion airport" is thousands of miles away. In the event of an engine failure, the remaining engine (such as the massive GE90) is powerful enough to maintain altitude and continue flight to a safe landing. Pilots are rigorously trained for this specific scenario. The 5.5-hour window is more than enough to reach a landing site from almost any point on a standard commercial flight path, making the 777 one of the safest and most reliable twin-engine aircraft ever built for long-haul travel.