 Flight testing of the Jimpu powered aircraft resulted in a crash, killing the flight test observer, (the first fatality during flight testing of Mitsubishi aircraft), blamed on the engines producing excessive drag, resulting in the switch to licence-built British engines.Eleven aircraft were built at Nagoya before production ceased, all of which flew domestic services for NKYKK (later to become Greater Japan Airways).During the Spanish Civil War, ten AS.6 Envoys were obtained by the Spanish Republicans, with the Nationalist side using two, including one that defected from the Republicans, as transport, reconnaissance aircraft or light bombers.