The OH-6A "Cayuse" is a small tactical helicopter was designed to be used as a military scout during the Vietnam War to meet the needs of the U.S. Army for an observation helicopter very easy to use light (LOH program). Initially sent to Vietnam in early 1968, the Hughes OH-6A was used for command and control, observation, target acquisition and reconnaissance. The Cayuse was organic to the division, brigade, battalion and unit size. The drop of water for four passengers in a "flying egg" (six-passenger with rear seats folded down) was a small, lightweight, robust, easy to operate a helicopter, with very low resistance.
The OH-6A Cayuse was quite effective when combined with the attack helicopter AH-1G Cobra as part of what were known as "Pink Teams". The OH-6A "Loach" (for "LOH") are low-flying targets, "trolling for fire", then marking the target with colored smoke to lead in a Cobra, or "Snake", to attack. The Cayuse could absorb a large quantity of small arms fire and still bring home the crew safely. The OH-6A could be armed with M27 armament subsystem, the port (left) barrel mounting M134 six 7.62 "Minigun" or a 40 mm grenade launcher on the XM8 armament subsystem. In addition, a 7.62 mm caliber pistol M60D machine could be mounted on the rear door opening starboard (right). The OH-6A replaced the Korean era OH-13 Sioux OH-23 light observation helicopters and Raven. The Hughes (model 500M) international military version was sold in ten countries and built under license in Italy and Japan. The Cayuse had a single articulated four-bladed main rotor and a metal two-bladed tail rotor. The OH-6A was driven by a single Allison T63-A turboshaft engine-5A 285 shp, and had a cruising speed of 144 mph (125 knots).
Two special operations versions of the OH-6A are the Hughes (model 500C) AH-6 "Little Bird" armed variant, and the MH-6 version for the transportation / utilities. These advanced versions feature a quieter five-bladed main rotor, minimum cavitation tail rotor and tail distinctive T-shaped