The Learjet 60 was announced in October 1990 as the replacement for the mid-size Model 55C, from which it is derived, and a proof of concept airframe flew for the first time on 18 October 1990 powered by one Garrett TFE331-3A and one PW305 engine. The first twin-PW305-powered Learjet 60 made its first flight from Mid-Continent Airport, Wichita, on 13 June 1991, and certification and early deliveries are tar-getted for the end of 1992. The Model 60 is the largest of the Learjet family and incorporates new fuel-efficient engines, a fuselage 0.07m wider and stretched by 1.43m, a 'glass cockpit', 'steer by wire' nosewheel, and an optional higher MTOW of 10478kg. Thrust reversers and single-point refuelling are also standard equipment, and the aircraft features a full galley, together with an aft toilet. By mid-1991, Learjet claimed to have sold the first full year's production to customers in seven countries.