Can sophisticated imaging technology solve the 77-year-old mystery of aviator Amelia Earhart's disappearance?
Forensic imaging expert Jeff Glickman believes that it can. Last week, The International Group for Historic Aircraft Recovery (TIGHAR)—which Glickman volunteers for—released new research claiming that a riveted aluminum piece found in 1991 is likely a patch from Earhart's plane.
Earhart disappeared in 1937, on an attempted round-the-world flight. People have been searching for her remains and her plane ever since.
Last week's announcement by the aircraft recovery group came after it was noticed that the 19-by-23-inch (48 by 58 centimeters) sheet of aluminum has a similar size and shape as a shiny patch that appears on the side of Earhart's plane in a 1937 photograph from the Miami Herald. This retrofitted metal piece covered a custom window that appeared in earlier photographs of Earhart's Lockheed Model 10 Electra.
Glickman set out to match the patch that's visible in the photograph to the aluminum sheet. "There were unique challenges in trying to do image interpretation and photogrammetry," he said, referring to the science of estimating measurements based on photographs.
"We had only a subsequent generation of the image, not the original, so we were combating many different distortions," Glickman said.
The photo analysis showed that the distance between a line of rivets on the patch matched the distance between the rivets seen in the photograph.
Despite last week's definitive headlines, however—"Aluminum Part Belonged to Amelia Earhart's Plane," "Amelia Earhart plane fragment identified"—Glickman still has months of work ahead in trying to confirm that the patch is from Earhart's plane.
After analyzing the Herald photograph, Glickman will now turn to hyperspectral technology—imaging that can pick up a vast spectrum of colors that are invisible to the naked eye—in an attempt to reveal more commonalities between the metal sheet and the photograph.
"We're not there yet," says Glickman, referring to the spectral imaging analysis. "We're still in process."
Forensic Photo Imaging
The Herald photograph does not show individual rivets on the patch, no matter how much the picture is magnified or enhanced. But slight shadows caused by the rivets' indentations are visible.
Through magnification and photogrammetry, Glickman said he used those shadows to match the rivet lines from the photo with those on the aluminum sheet.
Now he will use a hyperspectral camera to find any clues on the aluminum's thin surface layers. The clue could come in the form of a protective coating or an old mark from a fabricator's grease pencil—anything that might associate the metal piece with the one seen in the black-and-white photo.
While a regular camera sees in three color bands—red, green, and blue—Glickman's hyperspectral camera sees in 128 bands.
If he can find a unique feature that's visible both in the newspaper photo and the hyperspectral image of the aluminum, Glickman said, "then we have a match that would prove the metal originated from the aircraft."
Pascal Cotte, a spectral scanning expert who has brought the technology to bear on Leonardo da Vinci's paintings, among other objects, agrees the hyperspectral analysis could reveal clues. "This can give you a lot of information like traces, fingerprints, scratches, and pigment identification," he said.
But some aviation experts are skeptical of TIGHAR's theory and doubt that the patch belongs to Earhart's plane.
Elgen Long, who was the first to fly solo around the world over both Poles, spent decades investigating Earhart's disappearance and analyzed the same aluminum piece soon after it was found. He's firmly convinced that the piece is not from Earhart's plane.
"In 1992, we gathered five experts, including Edward Werner, a retired Lockheed engineer who actually helped build Amelia Earhart's fuselage," Long said. "Werner in particular said the piece wasn't from a Lockheed 10."
Instead, the experts concluded that the aluminum piece matched a U.S. Navy PBY Catalina seaplane of World War II vintage. "I went on top of a PBY myself with an exact pattern of the aluminum sheet," Long said. "It fit perfectly on top of the wing, just outboard of the starboard engine."
He added that the patch's metal composition is also consistent with the PBY.
Thomas King, an archaeologist for TIGHAR—a nonprofit foundation that is "dedicated to ... responsible aviation archaeology and historic preservation"—thinks the preponderance of evidence points to Earhart disappearing on a lonely atoll named Nikumaroro. The atoll is in the Pacific Ocean, some 350 miles (563 kilometers) away from her interim destination of Howland Island.
Earhart had taken off from New Guinea on July 2, 1937, accompanied by navigator Fred Noonan, as part of her attempt to be the first woman to fly around the world. In 1928, Earhart had become the first woman to fly solo across the Atlantic Ocean. (Read Amelia Earhart's first-person account of becoming the first pilot to fly from Hawaii to California.)
"The aluminum is another piece of data," said King. "We have a lot of data that, when put together, leads us to believe our hypothesis is correct: that Amelia landed on Nikumaroro and died there.
"But the only way we can be 100 percent sure," he added, "is to find human remains and get a DNA match."
If the aluminum sheet is more definitively linked to Earhart's plane, it could provoke more digging on Nikumaroro.
Archaeologist Fred Hiebert, a National Geographic fellow, said that "if such a link were to be established, I'd want to see cadaver dogs searching Nikumaroro for Earhart's remains."