CAC Woomera The CAC Woomera , also known as the CAC CA - 4 and CAC CA - 11 , was an Australian bomber aircraft , which was designed and manufactured by the Commonwealth Aircraft Corporation during World War II . The order for the Woomera was cancelled before it became operational with the Royal Australian Air Force ( RAAF ) . Design and development . In early 1939 , the Australian Government ordered large numbers of Bristol Beaufort bombers , to be built in railway workshops , and in doing so , by - passed the local aircraft company , Commonwealth Aircraft Corporation . CAC , under Sir Lawrence Wackett , began work on its own design , hoping to out - perform the Beaufort by building a machine that could serve as both a torpedo bomber and dive bomber . To keep down weight , Wackett dispensed with traditional self sealing fuel tanks and opted to make the wing cavities liquid - tight , and thus serve as fuel storage . The Australian Government was initially uninterested in the CAC design . However , in mid - 1940 , cut off from the supply of British - made components for the Beaufort program ( thanks to a British embargo on the export of aviation products , due to the need to maximise British production during the Battle of Britain ) , the Australian Government ordered a prototype of the CAC design , even before the Royal Australian Air Force had expressed a view about the machine . This prototype CA - 4 took to the air on 19 September 1941 . The CA - 4 was a low wing , twin - engined , multi - role bomber with a crew of three . It was armed with four nose - mounted . 303 calibre machine guns and two remote - controlled twin machine - gun barbette s mounted at the rear of the engine nacelles . It could carry either bombs , bombs or two torpedoes . It was originally powered by two Pratt & Whitney Twin Wasp R - 1830 - S3C3 - G radials . Unfortunately , the novel fuel tanks never proved reliable , and in January 1943 the CA - 4 prototype was completely destroyed in a mid - air explosion , probably due to a fuel leak . With a re - designed tail and rudder , and an improved nose armament of two 20 mm cannon and two . 303 calibre machine guns , the CA - 4 became the CA - 11 Woomera . Production . Faced with the crisis caused by the Japanese entry into the war in December 1941 , the RAAF accepted the design even before testing was complete , and ordered 105 examples of the CAC bomber on 8 March 1942 . However , after the loss of the first CA4 prototype , the redesigned CA - 11 did not fly until June 1944 . By the time production was due to commence , the dive - bombing concept had fallen into disrepute , the RAAF was filling the light bomber / reconnaissance / strike role with British - designed Bristol Beaufighter s ( which were being made in Australia by the Department of Aircraft Production ) ; US - made B - 24 Liberator heavy bomber s had also become available . Consequently , the original Woomera order was reduced from 105 to 20 . After the first CA11 flew , the whole program was cancelled and the production capacity set aside for Woomeras at CAC was switched to P - 51 Mustang fighters . Loss of CA - 4 . On 15 January 1943 , the prototype CA - 4 , " A23 - 1001 " , crashed on a test flight to assess powerplant performance and evaluate aerodynamic effects of a new fixed leading edge slat . During the return to the CAC airfield at Fisherman ' s Bend , the pilot , Squadron Leader Jim Harper , had detected a fuel leak in the port Pratt & Whitney R - 1830 engine . As the problem worsened he attempted to shut down the engine , feathering the propeller ; however , the actuation of the feathering switch caused an explosion and uncontrollable fire . The three man crew subsequently attempted evacuation at , yet only Harper succeeded in parachuting free , while the CAC test pilot Jim Carter and power plant group engineer Lionel Dudgeon were both killed . The airframe subsequently impacted south - west of Kilmore , Victoria . The wreckage was recovered and used for components .