The Lycoming O-540 is a six-cylinder, air-cooled, four-stroke aircraft engine commonly used in general aviation. It has a displacement of 540 cubic inches and typically produces between 250 to 300 horsepower, making it suitable for a variety of light aircraft. This engine is known for its reliability and efficiency, often found in popular aircraft models like the Piper PA-32 and Cessna 182. The O-540 features a horizontally opposed design, which helps maintain a low center of gravity and reduces vibration during flight.