The aircraft selected by CAC was the North American Aviation (NAA) NA-16, upon the recommendation of Lawrence Wackett. The selection was heavily fuelled by the relatively low level of difficulty involved in the manufacture of both the airframe and its Pratt & Whitney R-1340 Wasp radial engine. The application for the NA-16 was often viewed as being suitable for the trainer aircraft role, but that it could also play some role as a fighter-bomber as well, although there were doubts voiced by senior figures over its combat suitability. The selection was not without controversy as some voices within the Australian government were keen for aircraft manufacturing and development to be kept within the Commonwealth of Nations. In 1938, an inspection by Sir Edward Ellington of the then in-development Wirraway in 1938 led to him to express his opinion that the type should only serve temporarily in combat roles, and that the choice should be delayed to await the testing of a suitable British aircraft for the mission.