FILE-- In a 1937 file photo aviator Amelia Earhart and her navigator, Fred Noonan, pose in front of their twin-engine Lockheed Electra in Los Angeles prior to their historic flight in which Earhart was attempting to become first female pilot to circle the globe. A $2.2 million expedition is hoping to finally solve one of America's most enduring mysteries. What happened to famed aviator Amelia Earhart when she went missing over the South Pacific 75 years ago? (AP Photo, File)
Crew members lift an autonomous underwater vehicle from a ship to dockside waters in Honolulu on Sunday, July 1, 2012. The unmanned mapping vehicle will be used as part of a month-long voyage that begins Tuesday, July 11, 2012 to find plane wreckage from Amelia Earhart's Lockheed Electra, which disappeared over the South Pacific 75 years ago. (AP Photo/Oskar Garcia)
University of Hawaii ship Kaimikai-O-Kanaloa is anchored at harbor in Honolulu on Sunday, July 1, 2012. The ship will be used for of a month-long voyage that begins Tuesday, July 3, 2012 to attempt to find plane wreckage from Amelia Earhart's Lockheed Electra, which disappeared over the South Pacific 75 years ago. (AP Photo/Oskar Garcia)
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A $2.2 million expedition that hoped to find wreckage from Amelia Earhart’s final flight is on its way back to Hawaii without the dramatic, conclusive plane images searchers were hoping to attain.
But the president of The International Group for Historic Aircraft Recovery tells The Associated Press the group still believes Earhart and her navigator crashed onto a reef off a remote island in the Pacific Ocean 75 years ago this month.
Pat Thrasher said Monday that the group has a significant amount of video and sonar data to pore over to look for things that may be tough to see at first glance.
Thrasher says the underwater environment with steep cliffs, caves and vegetation was tougher to navigate than searchers expected.
The U.S. State Department encouraged the privately-funded voyage.