In 1983, the FAA-sponsored National Rotorcraft Program sought to identify improvements to the United States interurban transport networks and determined that conventional helicopters did not have the potential to satisfy requirements because of a lack of capacity, high operational costs and high noise levels. Tilt-rotor aircraft, it was felt, offered better potential to improve interurban air transport service. In 1985, FAA administrator D.D.Engen proposed a joint civil tilt-rotor study with NASA and DoD that would capitalize on development of the military Bell-Boeing V-22 and document the potential of the commercial tilt-rotor transport market. This study, conducted by Boeing Commercial Airplane Company teamed with Bell-Textron and Boeing-Vertol, led to several designs: CTR-22A/B/C and D, CTR-800, CTR-1900 and CTR-7500. The CTR-22A and B were direct civil derivatives of the V-22. With minimum change (all military equipment, including cargo ramp, removed), the CTR-22B provided seating for 31 passengers and included typical amenities. With an uprated transmission for higher horsepower (6805shp Allison T406 engines), the CTR-22B would achieve the 1100km design range. The CTR-22A did not meet this civil design range requirement.
A.J.Pelletier "Bell Aircraft since 1935", 1992
Technical data for Bell CTR-22B
Wing span: 13.96m, rotor diameter: 11.58m, overall span: 25.75m, overall length: 17.46m, height with rotors in upward position: 6.58m, take-off weight: 20440kg, cruising speed: 445km/h, range: 1110km