French investigators have formally identified a washed-up piece of airplane debris found in July on a remote island in the Indian Ocean as part of Malaysia Airlines Flight 370, a Boeing 777 that disappeared more than a year ago with 239 people aboard. Investigators have been examining the wing part, called a flaperon, since it was flown to a French aeronautical research laboratory near Toulouse last month. The discovery of the wing flap refocused the world's attention on the investigation, which many hope will finally yield clues to the plane's fate.