Air Chief Marshal Sir Christopher Moran was taken ill during a charity triathlon
The second most senior officer in the RAF has died after collapsing while taking part in a charity triathlon, the Ministry of Defence has said.
Air Chief Marshal Sir Christopher Moran was competing in the event at RAF Brize Norton in Oxfordshire on Wednesday.
The 54-year-old father-of-three had served as Commander-in-Chief of Air Command for the past 14 months.
Chief of Air Staff Sir Stephen Dalton said he was "a highly respected and courageous leader".
Sir Christopher, from Newton Ferrers, Devon, was president of RAF Triathlon and was competing in a sprint version of the event on Wednesday with about 80 other competitors.
It consisted of a 400m swim, 22km bike ride and a 5km run, and it was during the running stage that he collapsed.
He was taken by air ambulance to the John Radcliffe Hospital in Oxford where he was pronounced dead.
Paying tribute to him, Sir Stephen said: "It is with great sadness and shock that I announce the untimely death of Air Chief Marshal Sir Christopher Moran.
"A highly respected and courageous leader, this tragic loss comes as a huge blow to the Royal Air Force and, indeed, defence at large.
"Most importantly, our prayers and thoughts are with his family, to whom I offer my most sincere condolences on behalf of the Royal Air Force, serving and retired."
Sir Christopher had a distinguished career, starting out as a Harrier jump jet pilot before rising through the RAF ranks.
He served in the Falklands War, and later led RAF and Royal Navy fast jet operations in both Iraq and Afghanistan.
He also served as Equerry to the Duke of Edinburgh in the early 1990s.
In his spare time, Sir Christopher enjoyed skiing, sailing and reading military history. He was also admiral of the RAF Sailing Association.
He leaves wife Elizabeth and their two daughters, who are both at university, and a son, who is at school.