French and Malaysian experts have begun examining an airplane wing fragment that many people believe could offer the first tangible clue into the fate of the missing Malaysia Airlines Flight 370.

The metal piece washed up on the Indian Ocean island of Reunion and was sent to France where investigators from Malaysia, France and the U.S. 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 its metal with high-powered microscopes to gain insight into what caused the plane to go down. Malaysia Airlines Flight 370 vanished in March 2014 with 239 people aboard.

An Associated Press journalist saw Malaysia’s civil aviation chief and French air accident investigators arrive Wednesday to start the probe.

(AP)