(Reuters) - Researchers probing the 1937 disappearance of famed American aviator Amelia Earhart's plane said on Wednesday they now believe a slab of aluminum found decades ago on an uninhabited island in the Pacific Ocean came from her aircraft.
The warped piece of metal was uncovered on a 1991 voyage to the island of Nikumaroro in the Republic of Kiribati by The International Group for Historic Aircraft Recovery (TIGHAR), which has spent millions of dollars searching for Earhart's plane in a project that has involved hundreds of people.
"We don't understand how that patch got busted out of (the plane) and ended up on the island where we found it, but we have the patch, we have a piece of Earhart's aircraft," TIGHAR executive director Ric Gillespie said.
Earhart was the first female aviator to fly solo across the Atlantic Ocean.
The announcement that new analysis had determined the piece was from her lost craft was met with scepticism from some aviation experts, without independent review or a definitive marking such as a serial number.
Pennsylvania-based TIGHAR, which in 2012 made a naval expedition to look for remnants of Earhart's famed Lockheed Electra on the island, has been trying for years to determine the origin of the piece of metal, found on the island about 1,800 miles (2,897 km) southwest of Hawaii.
The piece, which measures about 24 by 18 inches (61 cm by 46 cm), did not appear to be a standard part of a Lockheed Electra, but TIGHAR researchers recently began to look into the possibility it might have been installed on the plane as a patch after a window was removed, he said.
On Oct. 7, a TIGHAR team examined a plane at Wichita Air Services in Newton, Kansas, that was similar to Earhart's aircraft. Because the plane was being restored, it was possible to look at its interior and see where the sheet of metal recovered in 1991 would have fit, Gillespie said.
Meanwhile, Gillespie's group plans another expedition to Nikumaroro in 2015.
"There are some in the aviation community and the historical community who are very skeptical of their claims," said Dick Knapinsky, spokesman for the Experimental Aircraft Association.
"How do you establish that a piece of aluminum belonged to a certain Lockheed Electra unless there's a serial number or something on it?" he said.
Reporting by Alex Dobuzinskis in Los Angeles; Editing by Sandra Maler