Hughes 500 (eng. Hughes 500; currently MD 500) is the designation of a family of light multi-purpose helicopters for civil and military purposes developed by Hughes Helicopters. Currently (2010) helicopters are produced by MD Helicopters.
The Hughes 500 is the civilian version of the OH-6 Cause, which won the US Army's competition for a new surveillance helicopter. A number of modifications of the vehicle were developed, including the MD 520N, which implemented the NOTAR concept, and the extended MD 600. Military versions of the MD 500 are called "Defender". Replaces the sparrow.