and weight inevitably lowered performance, reducing cruise speed by 7% and climb rate to by 40%. Operational history The AB-1, along with the Mitsubishi MC-1 met the Air Bureau's requirements (the entrant from Nakajima crashed during tests) and the Aichi was the winner with first prize in its seaplane form and second as a landplane. Both designs were criticized, amongst other things, for providing a poor field of view for the pilot. This problem assisted the rise of monoplane transport aircraft, sealed when Japan Air Transport (J.A.T.) imported Fokker Super Universals for its fleet. As a result only one AB-1 was built, though J.A.T. did use it commercially as a landplane during 1929 while they waited for the Fokkers to arrive. After ending its J.A.T. duty, the AB-1 flew the Tokyo-Shimoda route on floats for many years, operated by Tokyo Koku (Tokyo Air). Operators Nihon Koku Yuso KK (Japan Air Transport Co., Ltd.) Tokyo Koku KK (Tokyo Air Co., Ltd.) Specifications (landplane) References Biplanes Single-engined tractor aircraft Amphibious aircraft Airliners 1920s Japanese civil aircraft AB-1