01/31/2010. Remarks by Johan Visschedijk: "Bell Helicopter Company announced on June 22, 1973 that it had received a contract from the US Army to begin development of an Advanced Attack Helicopter (AAH). The US Army's RFPs (Requests for Proposals), issued in November 1972, resulted in submissions from Bell, Boeing Vertol, Hughes, Lockheed and Sikorsky. Those from Bell and Hughes were selected for development, and each company was to build two flight test prototypes, a ground test vehicle and a static test airframe.

Bell's proposal had the company designation Model 409 and US Army designation YAH-63. It was a twin-turbine helicopter, seating a crew of two in tandem, with the pilot in front. Features of the design included a low profile, large ventral fin and (replacing the aft-fuselage elevator of the Huey family) a horizontal surface at the tip of the upper fin, and the fuselage was of conventional semi-monocoque construction. Power plant consisted of two 1,500 shp General Electric T700-GE-700 advanced technology turboshaft engines.

The YAH-63 ground test vehicle was rolled out on January 31, 1975 and began ground running at Bell's Experimental Flight Test facility at Arlington, Texas, on 19 April 1975. The first flying prototype (22246) made its first flight at Arlington, Texas, on October 1, 1975, and was followed by the second (22247) on December 21, 1975. Both aircraft were delivered to the US Army during May 1976 for a four months fly-off competition against the Hughes YAH-64. The latter was announced winner on December 10, 1976.

Depending on the source the US Army serials for the two YAH-63s were issued in FY 1973 (73-22246 and 73-22247) or in 1974 (74-22246 and 74-22247). Most likely the latter is correct as the second prototype is preserved at the US Army Aviation Museum at Fort Rucker, Alabama, and is listed on the museum web site as 74-22247."