 A major priority of the specification was to introduce more direct supervision and observation of student pilots by instructors in order to reduce the rate of late-stage dropouts.On 11 September 1948, this specification was issued, attracting the attention of various aviation companies; the Air Ministry ultimately received in excess of 30 proposals.Percival was amongst those companies that decided to produce a response, their design has been attributed to the Polish-born aeronautical engineer, Henry Millicer (Millicer later moved to Australia, where he designed the award-winning Victa Airtourer light aircraft).