 On 3 July 1948, the Vampire became the first jet aircraft to equip peacetime units of the Royal Auxiliary Air Force, gradually replacing the de Havilland Mosquito in this capacity.On 23 June 1948, the first production "Vampire Fighter-Bomber Mk 5" (otherwise commonly designated as the "FB.5"), which had been modified from a Vampire F.3, carried out its maiden flight.The FB.5 retained the Goblin III engine of the F.3, but featured armour protection around engine systems, wings clipped back by 1 ft (30 cm), and longer-stroke main landing gear to handle greater takeoff weights and provide clearance for stores/weapons load.