Westland IV The Westland IV and Westland Wessex were high wing , three - engined light transport aircraft built by Westland Aircraft . The Westland IV first flew on 21 February 1929 at which time it was powered by the 95 hp Cirrus engine . This prototype was registered as G - EBXK and was certified for a crew of two and four passengers . The second machine had Hermes engines and a metal rear fuselage . The third machine , G - ABAJ , was modified to take the 105 hp Armstrong Siddeley Genet Major engines as well as some other changes and became the prototype Westland Wessex . The two Westland IVs were subsequently converted to Wessexes giving 10 aircraft in total . The Wessex was noted for its reliability and ability to make short landing runs . This made it attractive to Sir Alan Cobham in 1935 when he was looking for a small airliner to use for a service between Guernsey and the UK mainland . Previously , flyingboats had been used to provide a service between Portsmouth and St Peter Port on the island . There was no public airfield at the time on Guernsey , only the private airfield at L ' Eree run by the Guernsey Aero Club , of which Sir Alan was a member . The Wessex was certified as the only commercial aircraft to use L ' Eree . Cobham Air Routes Ltd used the following Wessex aircraft : G - EBXK - Westland serial number 1771 , granted its certificate of airworthiness on 21 March 1929 . Originally the prototype Westland IV and retained as a demonstrator , later converted to a Wessex and sold to Cobham Air Routes Ltd in 1935 and withdrawn from use in 1936 . G - ABAJ - Westland serial number 1897 , c . of a . 27 May 1930 . Built as a Westland IV and registered as G - AAJI , originally intended for service in Kenya with Wilson ' s Airways but the order was never taken up . Instead , G - AAJI was rebuilt as a Wessex and sold to Sabena with Belgian registration OO - AGC , before being in turn sold to Cobham in 1935 . This aircraft was used by Trafalgar Advertising in 1936 . G - ADEW - Westland serial number 1899 , c . of a . 6 August 1930 , sold to Sabena and registered as OO - AGF , then bought by Cobham in 1935 . Unfortunately , this aircraft was lost in the Channel on 3 July 1935 , 3 to 4 miles south off The Needles . The only passenger on board , a Mr C F Grainger , was picked up by the SS Stanmore and taken to Fowey . The pilot , W H Ogden , was presumed drowned within the aircraft and was never found . The blame was largely placed on Ogden , but was probably also due to the age of the Wessex airframes and their engines . This accident was the last straw for Sir Alan , who was struggling operationally , and he sold his airline to Olley Air Service . G - ADFZ - Westland serial number 1900 , c . of a . 30 August 1930 , sold to Sabena and registered as OO - AGF , and bought by Cobham in 1935 . G - ADFZ went on to work for Trafalgar Advertising with G - ABAJ , and it was decided to take G - ADFZ to Blackpool for the air display in September 1935 . On 7 September 1935 it was involved in a collision over Blackpool with an Avro 504N ( G - ACOD ) , the Wessex crashing in Cedar Square with the crew safe but all three occupants of the Avro being killed . Repaired , G - ADFZ was finally withdrawn from service 1 December 1946 .