 The Astra/Sparrow fire control system had been terminated by the government in September 1958 with all aircraft to employ the Hughes/Falcon combination.At the time of cancellation of the entire program, the first Arrow Mk 2, RL-206, was ready for taxi trials; Avro expected it to break the world speed record, but it never flew.Top speed would have been limited by atmospheric frictional heating, according to project engineer James Floyd, "[t]he aluminum alloy structure which we favoured was good for speeds greater than a Mach number of 2."