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Bob Edme, Associated Press
Malaysia's Department of Civil Aviation Director General Azharuddin Abdul Rahman, second left, arrives at the Direction Generale de l'Armement (DGA) facilities in Balma, near Toulouse, south-western France, Wednesday, Aug. 5, 2015 to start to examine an airplane wing fragment that many people believe could offer the first tangible clue into the fate of the missing Malaysia Airlines Flight 370. Malaysia Airlines Flight 370 vanished in March 2014 while flying from Kuala Lumpur to Beijing with 239 people aboard.

BALMA, France — French and Malaysian experts on Wednesday began examining an airplane wing fragment that could offer the first tangible clue about the fate of Malaysia Airlines Flight 370, which vanished more than a year ago with 239 people aboard.

Intact and encrusted with barnacles, the metal piece washed up on the Indian Ocean island of Reunion and was sent to France, where investigators will determine whether it's from the missing Boeing 777.

In addition to confirming the provenance of the 777 flap, analysts say the investigators will examine the metal with high-powered microscopes to gain insight into what caused the plane to go down as it flew from Kuala Lumpur to Beijing.

An Associated Press journalist saw Malaysia's civil aviation chief and French air accident investigators arrive to start the probe, and the French agency that investigates air crashes, known as the BEA, confirmed it was beginning. Experts from Boeing were also expected in the southern French town.

Analysts have said a close look at the metal of the part known as a "flaperon" could indicate what kind of stress the plane was under as it made impact. It won't fully solve the mystery of why the plane disappeared, nor will it help pinpoint where the plane crashed.

No other debris from MH370 is known to have washed up in the Indian Ocean.

A six-week air and sea search covering 4.6 million square kilometers (1.8 million square miles) of the southern Indian Ocean surface early last year failed to find any trace of the jet.

Authorities are working on a theory that the plane ran out of fuel, but some analysts argue that the apparent lack of damage to the piece of wreckage indicates a controlled landing on the ocean, with the jet sinking largely intact.

Another theory is that the jet plunged into the water vertically — high dive-style — snapping off both wings but preserving the fuselage. Yet another possibility, supported by a flight simulator, is that an out-of-fuel Boeing 777 would belly-flop heavily tail-first, disintegrating on impact.

Corbet reported from Paris. Associated Press writer Rod McGuirk in Canberra, Australia, contributed.