 Intensive discussions between Avro and the RCAF examined a wide range of alternative sizes and configurations for a supersonic interceptor , culminating in RCAF " Specification AIR 7 @-@ 3 " in April 1953 . AIR 7 @-@ 3 called specifically for crew of two , twin engines , with a range of 300 nautical miles ( 556 km ) for a normal low @-@ speed mission , and 200 nmi ( 370 km ) for a high @-@ speed interception mission . It also specified operation from a 6 @,@ 000 ft ( 1 @,@ 830 m ) runway ; a Mach 1 @.@ 5 cruising speed at an altitude of 70 @,@ 000 ft ( 21 @,@ 000 m ) ; and manoeuvrability for 2 g turns with no loss of speed or altitude at Mach 1 @.@ 5 and 50 @,@ 000 ft . The specification required five minutes from starting the aircraft 's engines to reaching 50 @,@ 000 ft altitude and Mach 1 @.@ 5 . It was also to have turn @-@ around time on the ground of less than 10 minutes . An RCAF team led by Ray Foottit visited U.S. aircraft producers and surveyed British and French manufacturers before concluding that no existing or planned aircraft could fulfill these requirements . 
