PARIS (AP) — French and Malaysian investigators cleared their last hurdle before launching a probe that many hope will solve the mystery of missing Malaysia Airlines Flight 370, meeting with a judge in Paris Monday after the arrival of a wing fragment that possibly belonged to the doomed aircraft.

Experts aim to determine whether the part comes from the plane, which disappeared on March 8, 2014, en route from Kuala Lumpur to Beijing with 239 people on board. The fragment was found on the French Indian Ocean island of Reunion and returned to the French mainland last week.

Malaysian officials left Monday's meeting without comment.

Air safety investigators, including one from Boeing, have identified the component as a flaperon from the trailing edge of a Boeing 777 wing. Flight 370 is the only missing 777 in the world and many — through deduction — are convinced the flap comes from the ill-fated jet.

Before the part arrived in France, investigators had a high-degree of confidence that the flaperon was from a Boeing 777, and therefore most likely from Malaysia 370. But there are a number of steps and tests that they must carry out before they can say that with 100 percent certainty, said aviation safety expert John Goglia, a former member of the National Transportation Safety Board.

"Investigators are ... going to wait until they have all the facts before they say definitively it's an apple or an orange," he said.

Photographs from Reunion showed a manufacturing code on the flaperon ending in BB, consistent with Boeing's numbering system. But Goglia cautioned that "other manufacturers could have used the same number."

"That BB number is a clue," Goglia said, "but it's not the final clue."

After investigators unpack the flaperon, extensive videos and photographs must be taken, he said. Then all parties to the investigation — including France, the U.S., Malaysia, Australia and Boeing — will study "every little scrap and dent," Goglia said.

Despite the arduous work ahead, Goglia said it shouldn't take very long for investigators to confirm whether the flaperon belongs to a 777, since Boeing likely has sent drawings and design requirements for the flaperon to France.

Investigators will measure to the space between the rivets and check the attachments used to connect the flaperon to the wing to see if they're consistent with a 777, he said. The whole flaperon will be extensively x-rayed, looking for any abnormalities in the honeycombs inside the composite material the piece is made from.

The attachments are especially important and will be examined using powerful electron microscopes, Goglia said. Failure analysis engineers will use the attachments "to try to determine what kind of forces broke it apart and what direction those forces came from," he said.

"That is going to be the goal," he said, "to determine how did this airplane strike the water? To determine, did this airplane break up in a million little pieces or ... gradually come down and hit water in relatively flat manner?"

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Thomas Adamson and Lori Hinnant in Paris, and Joan Lowy in Washington contributed to this report.