In September 1944, nine American airmen survived when their planes were shot down off the coast the tiny Pacific island of Chichijima.

Eight of the young men were captured by the Japanese, tortured and eaten.

The ninth drifted out to sea and was remarkably rescued by the US Navy.

That survivor was a 20-year-old pilot who would go on to become President, George HW Bush .

George HW Bush was the youngest Navy pilot during World War II. He is seen here in the cockpit of the Avenger. (AAP)

The extraordinary story of Mr Bush's rescue was well-known during his presidency, with a Navy seaman able to film the moment the lanky youngster was pulled from his tiny inflatable raft onto the deck of a submarine.

But the terrible fate of the other survivors was kept secret for many years.

Mr Bush was 17 when the United States entered the war after the Pearl Harbour attacks, and signed up to join the military the moment he turned 18.

After proving himself brilliantly in training, he became the youngest aviator in the US Navy, and was assigned to pilot a three-person Avenger dive-bomber in the Torpedo Squadron in the Pacific.

The mission

Mr Bush was part of a mission against the Japanese occupied island of Chichijima, 1000km southwest of Japan.

While flying over, the Avenger was struck by flak, setting his engine ablaze.

(Nine)

But rather than bail out immediately, Mr Bush kept flying out to sea, fancying the remote chances of rescue in the Pacific over the grim odds of being taken prisoner by the Japanese.

When the Avenger could fly not further, Mr Bush and his crewmates decided to bail out.

But while Mr Bush's parachute opened cleanly, one of his crewmate's didn't. The third did not escape the plane before it crashed into the water.

The 20-year-old lieutenant found himself the sole survivor of the crash, floating in the Pacific on an inflatable raft.

President George HW Bush's World War II experience played an influential part in shaping his presidency. (AAP)

"I'm not haunted by anything other than the fact that I feel responsibility for the lives of the two people that were killed," Mr Bush told CNN in 2002.

"I wonder why the chute didn't open for the other guy. Why me? Why am I blessed? Why am I still alive?

"That has plagued me."

The others

The fates of eight other US airmen who landed on Chichijima in raids on the island that month brings Mr Bush's luck into stark perspective.

The other Americans suffered horrible deaths as prisoners-of-war, ranging from beheading to being stabbed to death with bamboo spears and bayonets.

George HW Bush in the cockpit of an Avenger. (AAP)

Their deaths and the treatment of their bodies were documented in subsequent war crimes tribunals, but never published to spare their families additional grief.

It was not until the publication of James Bradley's book Flyboys: A True Story of Courage in 2003 that the awful truth became known.

Several of the airmen were sliced up and served as the main course in a lavish banquet held by senior Japanese officers on Chichijima, including a general and an admiral.

The cannibalism did not come out of hunger. The top brass on Chichijima had plenty of food. The atrocity was a gesture of scorn.

A Japanese medical orderly recounted how a surgeon sliced open one US crewman for a prime cut.

A document from a post-war trial listed some of the atrocities committed by Japanese forces on prisoners-of-war on Chichijima. (US Navy)

"Dr Teraki cut open the chest and took out the liver. I removed a piece of flesh from the flyer's thigh, weighing about six pounds and measuring four inches wide, about a foot long," the orderly said in a war crimes trial.

Another crewman's liver was served in small pieces with soy sauce and vegetables.

The rescue

Mr Bush had a terrifying wait in the hopes of rescue, drifting only a few kilometres off the shore of Chichijima.

A Japanese boat was sent out to capture him, but another plane in his squadron took a dive at it, scaring it off.

President George HW Bush died on Saturday. (AAP)

The other planes circled Mr Bush as a protective escort, albeit one very high up.

But his rescue did not come from above, but from below.

From underneath him an enormous dark leviathan emerged to retrieve him.

"I saw this thing coming out of the water and I said to myself, ‘Jeez, I hope it’s one of ours'," Mr Bush would say later.

It was the USS Finback , a submarine on its tenth war patrol.

Film footage showed Mr Bush climbing up the side of the Finback with the help of the submariners.

The aftermath

Three Japanese officers were later hanged after a US military commission on Guam sentenced them to death for their acts of torture and cannibalism.

Among them was the instigator, Major Sueo Matoba, whose justification for the war crimes was sickeningly banal.

"These incidents occurred when Japan was meeting defeat after defeat," he said.

"The personnel became excited, agitated and seething with uncontrollable rage.

"We were hungry. We tried every eatable animal and plant, like rats, mice, dogs and lizards. I hardly know what happened after that. We really were not cannibals."

Mr Bush's survival story was referenced repeatedly by his presidential campaign, with the footage of his rescue being used in campaign commercials.

But the fate of his colleagues was not known during his presidency.

The 41st President of the United States died on Saturday at the age of 94 .