Fifty-four years before Malaysia Airlines Flight 370 went missing another airliner vanished over the ocean. It just evaporated. To this day, just what happened to it is unknown, but speculation is rife – speculation fueled by the eyewitness report of those aboard a tanker who witnessed the craft’s destruction.

March 15, 1962 a Flying Tiger Line L1049H Super Constellation, bound from Agana Naval Air Station in Guam to Clark Air Force Base in the Philippines simply ceased to exist. N 6921C, Flying Tiger Flight 739/14, disappeared at 13º13’ North Latitude, 140º00’ East Longitude – over an all but bottomless patch of the Pacific, an abyss called the Mariana Trench. This deepest of all depressions in the Earth’s crust is an astonishing 6.78 miles deep – this compared to the relatively shallow 300-feet or so along MH370’s original projected flight path.

In all probability it’s the virtually bottomless depths of the Pacific that entomb the remains of “21 Charlie,” the call sign of the Flying Tiger Connie.

21 Charlie, operating as a charter flight for the Military Air Transport Service, was ferrying American Army personnel from Travis Air Force Base, California to Saigon, to a country we once called South Vietnam. There were 107 people on board that airplane. One of them was my stepfather. He was the co-pilot.

Bob Gazzaway was a pugnacious, plucky sort of guy who’d survived all that life could dish out – and that included being a Naval aviator during World War 11. In command of the Connie (the nickname of the Super Constellation), was Captain Gregory P. Thomas, one of Flying Tigers’ most experienced pilots.

21 Charlie’s path across the Pacific was placid. An Aircraft Accident Report obtained by this reporter from the U.S. Civil Aeronautics Board (the predecessor of the National Transportation Safety Board) says the weather that night was good – broken cumulus clouds, no turbulence, and moonlit visibility of 15 miles – the kind of night airmen relish.

At 22 minutes after midnight, 21 Charlie radioed its position. It was the last the outside world would hear from the crew. About an hour later the crew of the S/S T L Lenzen, a Standard Oil tanker, spotted an explosion in the sky. According to the CAB report, the crew spotted “a vapor trail, or some phenomenon resembling a vapor trail overhead…As this vapor trail passed behind a cloud, there occurred an explosion which was described by the witnesses as intensely luminous, with a white nucleus surrounded by a reddish-orange periphery with radial lines of identically colored lights.”

What happened? The CAB couldn’t determine a probable cause.

In the absence of hard physical evidence, rumors ran rampant, just as they have with Malaysia Flight 370. At the time people speculated about engine problems, sabotage, even the accidental shoot down of the Connie by an American missile, an inadvertent act that scuttlebutt said was covered up by an embarrassed Pentagon at the beginning of what would mutate into the most unpopular war in American history.

Lending at least anecdotal credence to the shootdown and sabotage theories is a statement by Captain Duilio Bona. The late award-winning investigative reporter David Morrissey and I obtained a copy of his declaration after filing a Freedom of Information request with the United States government. In his declaration, Captain Bona said some fascinating things. Among the more intriguing: the witnesses aboard the Lenzen were “convinced [that the craft they saw explode was “a U.S. Airplane…on [military] exercise flights.”

One of Bona’s crewmembers, a lookout named Scarfi said, “he saw a jet vapor track,” according to the captain. 21Charlie was a piston-engine airliner. Shortly after the vapor trial, Bona said Scarfi recalled, “a bright light illuminated, as a lightning, the bridge [of the ship].”

Lenzen’s radio operator said there were no distress signals from the aircraft, a statement that led the CAB to conclude in its Accident Report “It can be reasonably assumed” that whatever befell 21 Charlie “happened suddenly and without warning.”

Captain Bona said the radio operator of Lenzen tried “repeatedly” to contact Naval radio stations in Guam, Manila, Okinawa, and Iwo Jima – all to no avail. And that led to Bona’s conclusion “that what we saw was a troubled secret operation.”

Troubled by what, or by whom, Bona never said. A missile? Sabotage perhaps? Remember, this was the Cold War, and Vietnam was just beginning to heat up. In its report, the CAB said when 21 Charlie was parked at Honolulu, Wake Island, and Guam just about anyone could access the aircraft “without challenge…the aircraft was left unattended in a dimly lighted area for a period of time while at Guam.”

In a letter on the disaster the Federal Bureau of Investigation concluded the Bureau “did not anticipate [launching an investigation] unless substantial evidence of willful destruction is developed.”

Then there’s a more mundane theory: engine problems. Three days before it disappeared, 21 Charlie had to return to Honolulu when number four engine developed “a significant power loss.”

Shootdown, sabotage or something else? The odds are we’ll never know. 21 Charlie carried no flight data recorder, no cockpit voice recorder. The United States government says evidence of “willful destruction” was never recovered – this despite one of the most massive sea searches in history, a quest covering 144,000 square miles of ocean that employed 1,300 people, 48 aircraft, and 8 surface vessels. “Despite the thoroughness of the search,” concluded the Civil Aeronautics Board, “nothing was found which could conceivably be linked to the missing aircraft or its occupants.”

And so it is, 54 years after the fact, that the fate of the Flying Tiger Connie and 107 souls on board remains a mystery – a mystery the answers to which are shrouded by seven miles of water.

Now, we have a new mystery on our hands. Odds are it will be solved far before the passing of a half-century.