 By 1946 he had tested 310 different aircraft.Summers numbered among his firsts the first flight of a pure jet civil aircraft (the Nene-Viking, a Vickers Viking airframe fitted with Nene jet engines) on 6 April 1948, the first flight of civil turboprop airliner (the Vickers Viscount) on 16 July 1948 and the initial flight of Britain's first four-jet bomber (Vickers Valiant) on 18 May 1951.By the time he retired, he had achieved 366 general types, second only to the Guinness world record holder Eric "Winkle" Brown who has 487.