Hang on to your tin hats, here comes MH370 again. A piece of airplane has been found on a small island in the Indian Ocean, and to some, it looks very much like it came from the same model of commercial airliner that infamously disappeared without a trace in March 2014.

The section of wing was found on a beach in Réunion Island, a territory of France about 580 miles southeast of Madagascar. According to Xavier Tytelman, an airplane security expert based in France, a group of ecologists found the wreckage while doing a beach clean-up. A journalist on the island sent Tytelman photos of the wreckage, so he's done some armchair sleuthing. But investigators from Boeing and French aviation authorities are already working to determine for sure whether this is part of the missing plane by analyzing plane designs, part numbers, and weather patterns.

In case you missed it, Malaysia Airlines Flight 370 was a Boeing 777 carrying 227 passengers and 12 crew that went missing March 8, 2014, while en route from Kuala Lumpur, Malaysia to Beijing. It lost connection with ground control about an hour after takeoff, and a months-long search over thousands of square miles of ocean turned up nada. If this wing section does belong to the crash, it will dispel many theories, and bring the world a lot closer to closure.

You want it to be what you're looking for, but you have to put that aside and look at the facts of the case and you have to make a judgment. Richard Gillespie, director of the The International Group for Historic Aircraft Recovery

In the absence of verified serial or part numbers, the best place for investigators to start is figuring out what kind of plane the part comes from, and using circumstantial evidence to trace the wreckage back to a specific crash. Given the size of this wreckage—it's about six and a half feet long, according to Agence France Presse—it should be easy to figure out whether or not it came from a Boeing 777.

"All airplanes are unique, they have very distinctive features," says Richard Gillespie, director of the The International Group for Historic Aircraft Recovery (TIGHAR) in Pennsylvania. An inspector would look at the metal's thickness, its rivet pattern, and for other distinctive structures to try to link it to a specific model. Since receiving the pictures of the wreckage, Tytelman has been looking for matching parts. "In the beginning we didn't find anything that was correct," he says. Then a Boeing investigator sent him a black and white schematic of a 777's flaperon.

The drawing clearly shows the actuator fitting—the motor that moves the flap up and down—which Tytelman says perfectly matches the pictures. That would mean the wing came from a Boeing 777, and because exactly one Boeing 777 has ever been lost at sea...

Not so fast. "When looking at something like this you have to be as objective and unbiased as possible," says Gillespie. "You want it to be what you're looking for, but you have to put that aside and look at the facts of the case and you have to make a judgment." He would know—he and TIGHAR have spent decades investigating scraps of metal purported to have come from Amelia Earhart's lost Model 10 Electra.

Inspectors will have to compare the flaperon's structure with that of many different aircraft before they can be absolutely sure it came from MH370. There’s a good chance we’re looking at a totally different jet, Feith says. A Yemenia Airways Airbus A310 crashed in the ocean not far from Réunion in 2009, so “it could be part of that aircraft, or MH370, or some other wreckage from even some old airplane, who knows.”

"Maybe now that there's a big buzz about this, somebody someplace will find that it fits an Airbus," says Tytelman. "For me, it's finished."

If the flaperon is indeed from a Boeing 777, the inspectors would turn to circumstantial evidence to see how likely it is it came from MH370. "If it's from a 777, then it has to be a 777 that went in the water," says Gillepsie. And MH370 is the only Boeing 777 ever lost at sea.

But that doesn't mean the inspectors will light up their Gauloises and retire to the café for celebratory champagne (or whatever it is French inspectors do to celebrate) once they confirm the plane's model. They'll still need to confirm the piece of wing spent the requisite time at sea, and will want to get a better idea of how it made its way from wherever MH370 went down (still a mystery) to Réunion.

That'll be the tricky part. This particular beach is about 4,000 miles from the most likely MH370 crash sites. If this flaperon did come from MH370, it would probably have been carried by the Indian Ocean gyre, which moves clockwise. (If the wing had traveled by gyre, there would have to have been some insulation or trapped air to keep it afloat.) To check that theory, the inspectors would have to check the flaperon's paint and metal for corrosion, expecting to see damage that looked about a year old. Tytelman points out that the wing section does not have any sea grass on it, suggesting that it had not been at sea for long.

Boeing declined to comment for this story, but said it's helping French officials with the investigation—along with countless computer chair sleuths around the globe.