Photograph by Ben Curtis, AP
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Searchers comb the beach hoping to find additional airplane debris on Reunion Island in the Indian Ocean near the area where a piece of Boeing 777 wing washed up on July 29.

Photograph by Ben Curtis, AP

How a Piece of a Boeing 777 Drifted 2,300 Miles

Indian Ocean debris moves in predictable patterns and confirms searchers are looking in the right spot for the missing plane.

The discovery of an airplane wing section on a remote Indian Ocean island some 2,300 miles west of where investigators think Malaysia Airlines Flight 370 crashed off Australia comes as no surprise to scientists and mariners familiar with those seas. On Wednesday, experts confirmed the part is from the missing plane after testing it at a center near Toulouse, France.

“Floating debris from any source travels far and can persist for years,” says Marcus Eriksen, an ocean scientist who has sailed the fast-moving, circular currents known as the Indian Ocean gyre. “Currents are always going west at the top of the gyre. Depending on where debris is in this gyre, it is going to join this counter-clockwise rotation of trash before the ocean spits it out.”


Eriksen, who heads the 5 Gyres Institute, a California-based nonprofit focused on reducing plastic trash in oceans, told this reporter soon after Flight 370 disappeared that any debris from it would show up in Madagascar in about a year—a good guess as it turned out.

The piece, identified as a flaperon, which attaches to the trailing edge of the wing of a Boeing 777, would most likely have landed there if it hadn’t first bumped into Reunion Island, a French territory 600 miles east of Madagascar.

“It’s predictable that the debris would ride the subtropical gyre currents to potentially every island in its path,” he says.  

The discovery energized one of the most confounding and expensive searches in aviation history in several ways. It lays to rest the possibility–still believed by some of the victims’ families—that the plane was hijacked and sits parked in a secret hangar in Iran or Kazakhstan. It also confirms that the Australians, who are leading the search, are looking in the right place. The head of the Australian Transport Safety Bureau told reporters that the agency’s drift modeling shows the wreckage could have traveled from the search zone to Reunion Island.

What the discovery does not do, however, is to help locate the rest of the wreckage on the seafloor.  

Falling Off The Radar

Flight 370 was headed to Beijing with 239 people aboard when it dropped from radar about an hour after taking off from Kuala Lumpur. The plane turned west across the Malay Peninsula towards Penang. Satellite transmissions from the cockpit helped Inmarsat, a British satellite company, determine that the plane turned south and crashed seven hours later into the Indian Ocean off Australia after running out of fuel. The search area extends over 46,000 square miles (120,000 square kilometers), about 1,250 miles (2,012 kilometers) southwest of Perth. The region is so remote, searchers also are mapping the ocean floor for the first time.

“If you think about mapping over the past 150 years, the Atlantic has been pretty well mapped,” says John Fish, vice president of American Underwater Search and Survey in Bourne, Massachusetts. “World War I and World War II pushed mapping and also seafloor mapping. The Pacific is pretty well mapped. But when you get into areas that haven’t been traveled significantly by military or commercial traffic, there’s been very little presence.”

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French police officers carry a piece of wreckage identified as a “flaperon” from the edge of a Boeing 777 wing believed to be part of Malaysian Airlines Flight 370, which disappeared March 8, 2014 with 239 people aboard.

Floating debris from oceanic aircraft accidents provides essential clues that lead investigators to the wreckage beneath the surface. Using calculations known as “hindcasting,” debris pieces are plotted on a chart and backtracked over the ocean surface through time to their location at the moment the plane hit the water. Once the point of entry is located, the underwater search zone narrows considerably.

No debris from Flight 370 was ever spotted, despite a massive sea and air search. Now, 17 months after the plane’s disappearance, Fish says that pinpointing the spot where the flaperon hit the surface is next to impossible.  

“All of our operations have begun within a month of an accident and we usually find the aircraft within two weeks,” Fish says. “When you get into six months or longer, you get stuck. Then you’re dealing with unknown components of the cause of the drift, which have micro-changes all the time. Storms would affect it. Wind directions in storms. The longer it gets, the harder it gets.”

The flaperon’s months-long drift route could be recreated by modeling weather and ocean current data. But that wouldn’t be of much help.

“At the end of the day, you would end up with a larger search area than the one we have now,” Fish says. “That Inmarsat satellite data is pretty definitive.”

A more productive next step, he says, would be to search the rest of Reunion Island, as well as the shorelines of Madagascar and East Africa. One truism of aircraft investigations is this: if one piece of debris is found, there will be others.

A 150-ton Boeing jet has more than three million parts. If it broke up when it crashed, as the flaperon’s jagged edges suggest, hundreds of thousands of pieces could have bobbed along in the Indian Ocean.

Waves and Wind

In retrospect, the absence of any physical evidence from the crash shouldn’t have been that much of a mystery. By the time the search shifted to the Indian Ocean 10 days after the jet disappeared, the flaperon was already on its way and riding the current towards Africa.

“A very large anti-clockwise rotating current sweeps right up the west coast of Australia and into the tropics, where it heads west,” says Matt Jolly, a New Zealander who traverses those currents as captain of the Braveheart, a 130-foot expedition ship. “It is these very same currents and winds that the sailors of old used in the spice trade, making use of this superhighway to get from Europe to the East Indies and back again.”

How and where drifting debris travels from one point to another is determined by currents, winds and the shape of the piece, which affects how deep or high it floats.

“So, while the debris all start off together, as time goes on their locations diverge, mainly because of the shape of the piece and how much of it is hanging in the currents or how much of it is exposed to the wind above the water,” says John Purvis, the former chief of Boeing’s accident investigation team.

That is why investigators are not as confident that a battered suitcase found near the flaperon also drifted over from Flight 370. The large, bulky wing section is filled with honeycomb in sealed compartments that keep it buoyant. But what kept the suitcase from sinking?

Eriksen, who studies how UV rays and the relentless action of waves can reduce a plastic bottle to confetti in mere months, says they could have drifted together, regardless of their differences in size and shape.

“Both the plane wing and the suitcase are riding the same currents,” he says. “I wouldn’t expect one to outrun the other.”

But the suitcase’s travels easily could have a less exotic origin. It could just be garbage. Remember early in the search when the shadowy images from the French, Chinese and Thai satellites were thought to be Flight 370 debris? All of it turned out to be ocean trash.