TIGHAR speculates that the hard landing made by Earhart upon her arrival in Miami on May 23, 1937, may have caused the fuselage to flex enough to crack the window.
“With no time to order a new window to be specially made, they may have decided to just replace it with a simple patch,” Gillespie said.
The possibility that Earhart and Noonan made an emergency landing on Nikumaroro was examined by the Navy in the first days following the flight's disappearance.
“They did search the atoll, but only from the air," Gillespie said.
In 10 archaeological expeditions to Nikumaroro, Gillespie and his team uncovered a number of artifacts which, combined with archival research, provide strong circumstantial evidence for a castaway presence.
“We found archival records describing the discovering on Nikumaroro in 1940 of the partial skeleton and campsite of what appears to have been a female castaway," Gillespie said.
"We identified the place on a remote corner of the atoll that fits the description of where the bones and campsite were found. Archaeological digs there have produced artifacts that speak of an American woman of the 1930s," Gillespie said.
He added that evidence on the island would also suggest that Earhart survived as a castaway "for a matter of weeks, possibly more."
Other clues came from another photograph of Nikumaroro's western shoreline taken three months after Earhart's disappearance. It showed an unexplained object protruding from the water on the fringing reef.
Forensic imaging analyses of the photo suggested that the shape and dimension of the object are consistent with the landing gear of a Lockheed Electra.
An “anomaly” that might possibly be the wreckage of Amelia Earhart's aircraft emerged from analysis of the sonar imagery captured off Nikumaroro during TIGHAR’s last expedition.
According to the researchers, a possible scenario is that the airplane was washed over the reef edge and broke up in the surf, scattering torn aluminum sheets, which was then carried off by ocean forces. Some of the torn aluminium apparently later washed up on the island -- the 2-2-V-1 sheet being one of them.
“At this time, we can’t say the repair of metal sheeting matches the Nikumaroro aluminium. It’s another hypothesis to be tested. We've been disappointed before and we may be disappointed again, but the potential is there for the proof that everyone has been looking for,” Gillespie said.
A new expedition to search for pieces of Earhart's plane is scheduled to take place in mid-September, mid-October. The probe will rely on two manned submersibles, each carrying a pilot, a TIGHAR observer and an ocean scientist.