In 1982 the U.S. Army started the Light Helicopter Experimental (LHX) program to replace UH-1, AH-1, OH-6, and OH-58 helicopters. This requirement was changed to a reconnaissance helicopter by 1988.
Request for proposals for the new helicopter type were released in June 1988. In October 1988, the Boeing-Sikorsky and Bell-McDonnell Douglas teams received contracts for their designs. The program's name was changed to Light Helicopter (LH) in 1990. In April 1991, the Boeing-Sikorsky team was selected as the contest winner and received a contract to build four prototypes.Also that month the helicopter was designated RAH-66 Comanche by the Army.In 1993, the first prototype began assembly. The following year the number of prototypes was cut to two.
On 23 February 2004, the U.S. Army announced their decision to cancel the Comanche helicopter program in view of the need to provide funds to renovate the existing helicopter fleet of aging attack, utility, and reconnaissance aircraft.The Army also planned to use Comanche program funds to speed up unmanned aerial vehicles (UAVs) development.UAVs have proven their worth providing reconnaissance in support of military operations in Afghanistan and Iraq. About US$6.9 billion had already been invested in the Comanche program at the time of its termination.An additional US$450–680 million was required in contract termination fees to main program partners Sikorsky and Boeing Integrated Defense Systems.