The war demonstrated the importance of naval airborne early warning (AEW). Vital to British success was the protection of the two Royal Navy aircraft carriers, HMS "Hermes" and HMS "Invincible". In 1982, the Royal Navy had effectively zero over-the-horizon radar capability, so to protect the British naval taskforce several destroyers and frigates were sent on radar picket duty to form the first line of defense against Argentine air attacks. As a result, the British lost the Type 42 destroyer HMS "Sheffield" to fire following an Argentine Exocet missile strike. Following the conflict, the Royal Navy modified some Westland Sea King helicopters for the AEW role. Other navies (including France, Spain and Italy) have since included AEW aircraft or helicopters on their carriers.