The Duke of Cambridge has qualified as an operational search and rescue captain, Clarence House said on Thursday.
William - known as Flight Lieutenant Wales in the military - has previously only co-piloted RAF Sea King helicopters but will now be able to command operations.
Prince William, whose rank remains Flight Lieutenant as it is a qualification rather than a rank promotion, completed two days of ground and air-based tests to achieve the qualification, following two years of flying experience.
The mock rescue scenarios saw him take part in an airborne search for a yacht, a search for two missing kayakers, a search for people in water and extinguishing a simulated fire on a large survey vessel.Officer Commanding 22 Squadron, Wing Commander Mark Dunlop, said: "Flt Lt Wales demonstrated the required standards needed for the award of Operation Captaincy.
"Due to the nature of search and rescue operations, the required standards are always set at a very high level.
"Operational Captaincy carries the overarching responsibility for the safety of the aircraft, its crew and any casualties."
Prince William, second in line to the throne, joined C Flight, 22 Squadron at RAF Valley in Anglesey in September 2010.
The Prince was only recently celebrating his grandmother, the Queen's, 60th anniversary as the head of state.
He appeared alongside his wife, the Duchess of Cambridge, and his brother Prince Harry at the 1,000 ship Thames pageant, as well as the Jubilee concert and the celebratory services at St Paul's Cathedral.
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