In June 1955, a semi-navalised prototype, "XF828", was completed for the purpose of conducting carrier flight deck suitability trials. For this purpose, XF828 featured several changes, including the alteration of the profile of the wing leading edges and the strengthening of the wings, as well as underwing fixture points for catapult launches, and a tailhook for arrested landings; however, the Sea Vixen lacked a wing folding mechanism, or racks for armaments. On 20 June 1955, this aircraft made its first flight from de Havilland's facility at Christchurch Airfield in Dorset. The following year, XF828 performed its first arrested deck landing on the Royal Navy's aircraft carrier .