Scobell was assisted by two experienced aircrew with whom he had flown many combat missions: William P. Walton, from Talco, Texas, was his radioman and bomb aimer and John F. Gelnaw was the gunner.

This was the ninth intensive air strike on Japanese positions around the South China Sea since January 2, when Vice-Admiral John McCain's Task Force 38 sailed through the Straits of Luzon as part of Operation Gratitude, designed to support General MacArthur's Lingayen Gulf landings and cut off vital shipping routes from Tokyo to Southeast Asia. It is only possible to speculate as to the level of cumulative fatigue felt by the pilots and their crew after two weeks of intensive combat.

Hunt and Scobell flew in a formation of eight TBMs, part of the third wave in a number of strikes on Hong Kong on January 16 that had commenced at 0845 hours. Hainan and Canton were ancillary targets for the mission but Hong Kong bore the brunt of this massive assault, with 138 aircraft attacking in the morning and 158 attacking between 3pm and 4.45pm.

As Hunt and Scobell approached from the south, each aircraft armed with a 2,000-pound bomb intended for Japanese shipping anchored in Victoria Harbour or Kowloon Docks, the stormy skies cleared and their targets were exposed under a cloudless winter sky. Flying in close formation at 13,000 feet they began their bombing descent above Mount Parker at a speed of more than 200 knots. Hunt led the second section of the first division with Scobell just below and behind him, as usual.

What happened next was seen and recorded by several eye witnesses, including George Gerrard, an inmate of Stanley prison camp, who wrote about the incident in his diary.

"We saw 8 planes in one formation and 5 in another just behind. They appeared like silver bullets in the sky when suddenly we saw the left hand plane in the first formation swing over to the right and strike his companion. A terrific sheet of flame shot out and the first plane came lurching down, but the pilot bailed out and then the second plane made a big effort to get under control but to no avail, the fellow jumped but was caught in his incline and eventually crashed in the region of Mount Parker, also a wing came slowly to the ground."

The two friends had collided in mid-air while trying to evade heavy anti-aircraft fire. A respite between raids had allowed the highly skilled Japanese anti-aircraft crews to prepare for the assault with a new tactic: creating thick barrages of flak at fixed altitudes. Hunt's TBM was on fire and out of control and with his legs badly burned, he pulled the starboard canopy slide and bailed out while his aircraft plummeted into the mountain below, creating a huge plume of smoke that can clearly be seen in photographs taken by warplanes on the subsequent bombing run. His two crewmen were killed instantly and Gahran's 20th birthday was never celebrated. Scobell fought to control his plane before bailing out himself but his parachute became entangled in the aircraft and he and his two crew met their death slightly further down the same slope.

The US Navy report into the battle described the event: "It is thought that the mid-air collision that occurred at this time may have been caused by the concussion of an exploding shell of large calibre as several pilots reported being thrown around by the fire."

The intensity and accuracy of the Japanese anti-aircraft fire over Hong Kong that day was the worst that any of the experienced pilots had ever encountered. As the same official report noted: "The topography of the Hong Kong area permitted a concentration of fire so intense that it is surprising any planes got through."

In all, 154 tons of munitions were dropped on Hong Kong that day, although the Americans admitted that the successes were not commensurate with the loss of 17 aircraft (many of which came down in the harbour), 14 pilots and 15 aircrew. The village of Hung Hom, being close to Kowloon docks, was devastated, with hundreds of civilian casualties. A large oil tanker was the only ship sunk but others were damaged, Taikoo docks were virtually levelled, Kai Tak airfield was made unusable, buildings were destroyed at the Royal Navy Yard and Stonecutters Island, and the Texaco oil depot was set ablaze.

The Japanese high command was convinced this massive air assault, sometimes referred to as the Second Battle of Hong Kong, was the prelude to a major Allied land invasion of China.

(and as reported by the in May, 2013), a local amateur war historian stumbled upon the shattered wreck of Hunt's aircraft, concealed under dense vegetation, in the upper reaches of Tai Tam Country Park. By investing hours in assiduous research and by using a friend's collection of records and diaries from the internment camp at Stanley, Craig Mitchell was eventually able to identify the aircraft. He has meticulously sourced declassified US Navy war records, letters to crew members' families, aerial photographs, logs and obituaries to piece together the story of that day. He also located the crash site of Scobell's aircraft and its 2,000-pound bomb further down the mountain, although most of the wreckage has been cleared over the years. The bomb from Hunt's aircraft has, as far as is known, never been found.

"I have the original squadron reports, carrier report and task force report that all corroborate the two TBM Avenger planes colliding in that location on that day," says Mitchell, as he points out the triangular armoured plate leaning against a tree root that would have been part of the pilot's seat, behind Hunt's head. Hong Kong-born Mitchell says he has left everything as he found it.

His research has also revealed what happened to Hunt after he bailed out of the burning aircraft.

"Finally, I found a record for Lieutenant R.L. Hunt, who was admitted to Ofuna POW camp in February 1945, wrapped in bandages with third-degree burns and a fractured left arm," says Mitchell, sitting with other members of the team he has put together to study and retrieve the wreck in a boulder-strewn clearing, close to the crash site. From here you can gaze up at the sky above Mount Parker where the two aircraft collided.

Ofuna was a notorious prisoner of war camp near Tokyo that was reserved for the torture of airmen and submariners who might be of intelligence value to the Japanese military.

"After a while I found a picture of Hunt, the guy I had been researching for months - you almost feel you know this character who bailed out over Tai Tam 70 years ago," says Mitchell, holding the photograph of the handsome young man in naval uniform.

Accounts found by Mitchell, and recorded clandestinely by Allied prisoners, indicated that Hunt died after receiving an injection from the duty camp doctor on February 25, 1945. The heroic pilot with film star looks would have died in agony many thousands of miles from Kansas City.

Mitchell, a sports facility and events manager, plans to excavate and recover Hunt's TBM Avenger, Number 124, from Tai Tam Country Park and has recruited local specialists to help. He is seeking funding for Project Avenger, in order to carry out a professional archaeological survey of the site, recover and restore the artefacts and bring the plane down from the mountain for display in the Hong Kong Maritime Museum, so the story of that day can be better understood.

"It's an original piece of Hong Kong history - there are no other warplanes with all the recognisable parts just a sneeze from Stanley and Repulse Bay," says Mitchell.

Despite the overwhelming evidence so far accrued, a small piece of the historical jigsaw remains missing.

"If we can just find BuNo [the aircraft serial number] 46438, it will confirm everything and we could make an approach to the families with the information. Maybe they would like to visit the site," says Mitchell.

There is another aspect troubling Mitchell, although he is reluctant to talk about it.

"I saw a picture from Keokuk National Cemetery, in Iowa [in the United States], with the five aircrew listed on a single headstone. I think it is significant they did not distinguish between the two [crash] sites. It made me suspicious," he admits.

Mitchell explains that, in the years after the war in Asia, the remains of US military aircrew were recovered by a team known as JPAC (Joint POW/MIA Accounting Command). In the lower crash site, which Mitchell believes to be that of Scobell's aircraft, he found a pile of parachute harnesses, indicating that the bodies had been removed, either by the Japanese or, more likely, by JPAC, for repatriation back to the US for proper burial. However, the upper crash site is very remote and hard to find. He also points out that, from 1948, as the Communists gained the upper hand in the Chinese civil war, there were genuine fears about the future of Hong Kong, so the pressure was on to get the job done and get out of the territory.

So is it possible that the remains of Barrow and Gahran have been on Mount Parker for 70 years?

"We have informed the US Consulate about the crash site and their records clearly indicate that all bodies were recovered and this is a closed case but I suspect once [JPAC] were 100 per cent certain the guys were dead, they would have moved on. It was a high impact crash, it's a long way up this hill and, if you didn't know exactly where you were going, it could take you a year to find it.

"Why a joint grave for five airmen if there were separate sets of remains?" asks Mitchell.

Stooping under branches and looking at the array of twisted metal debris and contorted engine parts, it's profoundly troubling to consider the possibility that human remains might still be up in the country park. Gahran's burial at Keokuk cemetery was reported in the on January 13, 1950, almost five years after he died, and it's assumed services for the other four airmen whose names are on the headstone were conducted on the same day, although Mitchell prefers to focus on the tangible.

"The most important thing is that, if we do nothing, it might all be gone soon and the story of those brave US Airmen could be forgotten. Let's keep the memory alive," he says.

"Let's be clear, this is an archaeological project," says Dr Mick Atha, adjunct professor at Chinese University and the archaeologist attached to the project. "If we did find human remains, the first thing would be to bring them to the attention of the local police. If they were content that this was a second-world-war crash site, not a potential crime scene, then we would need to contact the US Consulate and seek their advice before proceeding."

Atha has compiled a detailed project plan for approval by the Antiquities and Monuments Office that identifies a survey area measuring 50 metres by 30 metres. A team from Polytechnic University will conduct a photogrammetric site record before Atha moves in to record every item and sweep through with metal detectors, searching for smaller objects, such as dog tags.

"Sometimes the smallest objects tell the biggest stories and the small BuNo plates will be crucial for this project. Dog tags would be amazing to find, if they are still there," says the archaeologist. "The ballpark figure to fund the project is HK$1 million, but the cost of the helicopters needed to transfer the heavy stuff down the mountain is still being finalised.

"It's not big money compared with the HK$3.1 billion being spent in To Kwa Wan [to protect a well and other ancient relics], but we still need to find it.

"I always tell my students, archaeology is not just digging up old stuff - what we are really interested in is people and giving them a voice," says Atha.

"If we don't recover these items soon they will rust and degrade out of existence," says Paul Harrison, a curator and conservator, who has been seconded to Project Avenger by the Maritime Museum. "This really is the last chance to see.

"What I would like to do is have a replica TBN Avenger built and displayed with arrows pointing to the real artefacts like the machine guns, landing struts, armour plating and instrumentation recovered professionally from the mountain and preserved," he says.

"It's weird," says Mitchell, as he examines a crumpled section of fuselage on which the navy blue paint can still just be made out. "For all of those six airmen, I probably know more about them than anyone else in the world - even their own families.

"It doesn't seem right just to leave it all here, rotting - it's sort of disrespectful really."

The hope is that someone will step forward to help fund Project Avenger and protect this part of Hong Kong's modern history and the memory of those six brave young Americans.

By the same author: A respected foe in WWI Hong Kong