MD Helicopters MD 500

The MD 500 is a family of light utility helicopters, civil and military, developed from the Hughes 500, itself the civil version of the US Army's OH-6A Cayuse. The OH-6 prototype made its maiden flight in February 1963 after Hughes won the Army's Light Observation Helicopter competition, and the type was introduced in 1967. It was built first by Hughes Helicopters, then by McDonnell Douglas Helicopter Systems after McDonnell Douglas bought Hughes in January 1984, and by MD Helicopters after Boeing sold the line in early 1999. The 500D of 1976 added a more powerful engine, a T-tail and a five-blade rotor, the 500E followed in 1982, and the 530F is a hot-and-high version. The MD 520N replaced the tail rotor with the NOTAR system. Popular with civil, utility and police operators, it has also served with air forces such as El Salvador's.