First World War flying ace John Herbert Hedley might well have been the luckiest man alive.

Captain Hedley was the observer in a Bristol F.2B biplane fighter piloted by fellow air ace Lieutenant Reginald “Jimmy” Makepeace when they were caught in a dogfight Jan. 4, 1918.

To escape machine-gun fire Makepeace put the aircraft into a steep nosedive. Hedley experienced what is known as “negative Gs,” the feeling roller coaster riders get as the car starts its steep descent and they are lifted up in their seats.

But roller coaster riders are strapped in. Hedley wasn’t. And members of the Royal Flying Corps were not then issued parachutes.

So, Hedley fell.

One school of thought is that he caught the aircraft’s slipstream. Slipstreams are air currents created by an aircraft (or a goose) that give a free lift follower riding in the sweet spot between the downwash and upwash. A slipstream would enable Hedley to fall at the same speed as the aircraft as it plunged about 100 metres. When the craft levelled out, Hedley landed on the tail of the plane and crawled back into the cockpit.

Another theory is that Hedley fell out of the aircraft, but like air ace Raymond Collishaw, a fighter pilot ejected from his aircraft doing a similar manoeuvre six months earlier, managed to grab onto part of the plane as it fell, then crawl back into the cockpit.

“Whether he actually came out then tumbled down a few hundred feet and fell back in again, he would be very, very lucky,” said John Stelling of the Land, Sea and Air Museum in Newcastle upon Tyne in Britain in a BBC interview.

Accounts of the incident vary.

“I’m living on borrowed time and how well I know it. It certainly took a lot of whisky and soda to get over that one.”

An entry in the 1929 book Luck Your Silent Partner, quoted a log entry by Lieutenant R.C. Purvis, of 10 Squadron, recorded on Jan. 6, 1918: “Mach. No. 7255, Height 15,000 feet. Captain J.H. Hedley accidentally thrown into the air, afterwards alighted on tail of same machine and rescued.”

After the biplane returned to the ground, Hedley, 31, went up on two more flights as a gunner on artillery patrol, says an account in The Luckiest Man Alive, The Life of World War I Aviator Captain John H. Hedley by Lothrop Stoddard. Hedley said it took two weeks before the shock kicked in.

“He began to realize that if his plane had been two feet out of line, had side slipped or possibly had continued its dive for any greater distance, he would have been a goner…He told a reporter, ‘I’m living on borrowed time and how well I know it. It certainly took a lot of whisky and soda to get over that one.’”

A newspaper story after the war describes Hedley’s speech to a Rotary Club luncheon in the United States.

“Captain Hedley described an experience which he had as an observer. Observers were not strapped in the airplanes and when the pilot caused the machine to dive suddenly, Hedley was thrown forward in the air. He had, however, retained his grasp on the machine gun and when the ‘plane straightened out he was flung back upon the fuselage. He then managed to crawl back into the cockpit.”

On March 27, 1918, Hedley’s luck held again when he and his pilot Captain Robert were shot down, captured and sent to a prisoner of war camp. Makepeace was not so lucky. He died in a crash on May 28, 1918.

Chicago Tribune War correspondent Floyd Gibbons labelled Hedley the “luckiest man alive.” Hedley capitalized on the moniker, emigrating to the United States where he was popular on the lecture circuit in the 1920s and ’30s. He became an accountant and died in Los Angeles in 1977.