Powered by two Alvis Leonides 531 radial engines, the Twin Pioneer was a high-wing cabin monoplane with a triple fin and rudder assembly and fixed tailwheel undercarriage. The prototype Twin Pioneer, registered G-ANTP, first flew at Prestwick Airport on 25 June 1955. Flight trials proved that the aircraft had a very short landing run and the aircraft was displayed at the September 1955 Society of British Aircraft Constructors Show at Farnborough.
In 1958, the 33rd aircraft was used as a prototype for the Series 2 with Pratt & Whitney Wasp R-1340 radial engines which had been ordered by Philippine Air Lines. A Series 3 aircraft was also developed to use the improved Alvis Leonides 531 radial engine.Three pre-production aircraft were built for trials, and sales and demonstrations.
In 1958, the 33rd aircraft was used as a prototype for the Series 2 with Pratt & Whitney Wasp R-1340 radial engines which had been ordered by Philippine Air Lines. A Series 3 aircraft was also developed to use the improved Alvis Leonides 531 radial engine.Three pre-production aircraft were built for trials, and sales and demonstrations.