A helicopter carrying Britain's Prince Charles and his wife Camilla had to make an emergency landing after it began lurching to one side, investigators revealed on Thursday.
The pilot of the Sikorsky S-76C chopper, which was carrying the 65-year-old heir to the throne and five other passengers to Wales on May 23 last year, had to land at Denham aerodrome west of London, a report by the Air Accidents Investigation Branch (AAIB) said.
The helicopter landed safely and the royal couple made the rest of their journey to Wales' Hay-on-Wye literary festival by car, arriving three hours late.
At the time, a royal source described the emergency landing as "quite a hairy incident".
The AAIB said the helicopter's 53-year-old captain had declared a 'Pan' emergency, a less serious warning than a Mayday.
He carried out a "running" landing -- used if an aircraft has a problem -- and the "abnormality" was still apparent as the helicopter taxied on the ground, the report said.
The AAIB said the fault was later traced to the splitting of a metal ball within a system which helps control "yaw", or veering, which caused a leak in hydraulic pressure.
Once at Hay, Charles and Camilla were reported to be relaxed and smiling, with neither alluding to the drama.
The report comes after two fatal helicopter crashes in Britain in recent weeks.
Four US airmen were killed in eastern England on Tuesday when their helicopter ditched onto marshland while flying low on a training exercise.
In Scotland's biggest city Glasgow, a police helicopter crashed into a busy pub on November 29, killing all three crew and seven people on the ground.
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