Why Can't We Solve the Amelia Earhart Mystery?

Earhart had set many aviation records, and her dream was to be the first woman to fly around the world, using the longer route along the equator. On July 2, 1937, Earhart and Noonan departed Lae, Papua New Guinea, for the longest stretch. Their destination was Howland Island, a tiny 1.5 mile by 1/2 mile-wide (2.4 by 0.8 kilometers) atoll rising a mere 20 feet (6 meters) from the South Pacific. They had around 7,000 miles (11,265 kilometers) left in their journey; this 24-hour flight to Howland covered about 2,500 miles (4,023 kilometers). After they abandoned every unnecessary item aboard the plane, they still had only just enough fuel to make it to Howland. There could be no margin for error, and to ensure their safety, a Coast Guard cutter named Itasca tracked them using radio and two additional ships burned all their lights to serve as markers along the route.

Noonan tried to use celestial navigation to find his way, but the skies were overcast during the stretch. The pair also fell out of radio contact with the Coast Guard. After dawn, the Itasca picked up a transmission from Earhart. She said that by Noonan's reckoning the plane should be just over the Itasca. It was moored just off Howland Island, but Earhart said their fuel stores were running low. An hour later, another radio transmission came from Earhart: "We are running north and south," she said [source: Family of Amelia Earhart].

That was the last transmission. Earhart and Noonan were never heard from again.

President Franklin D. Roosevelt ordered a massive search for Earhart by the U.S. Navy, covering some 250,000 square miles (647,497 square kilometers) of ocean -- and spending $4 million in the midst of the Great Depression -- to find evidence of her fate. Although searchers scoured Howland Island and the surrounding sea, no wreckage was discovered. It was as if Earhart and Noonan simply vanished into the mist.

Once attention turned from Howland Island in the years to follow, however, potential clues to the disappearance of Earhart and Noonan would begin to turn up.

Toward the end of its search for Earhart in 1937, the Navy sent a destroyer to an uninhabited atoll called Gardner Island, now known as Nikumaroro. It is located 400 miles (643 kilometers) southeast of Howland. Radio transmissions on the frequency Earhart had been using were being broadcast sporadically from that area. The search was called off after two observation planes launched from the ship turned up no evidence of human life.

Perhaps that would have been the end of the association between Earhart and the island, had it not been colonized by the British a year after her disappearance. In 1940, Gerald Gallagher, the lead official on the island, discovered evidence that a castaway had inhabited the island before it was colonized. Among the finds were the sole of a woman's shoe, a man's shoe, a liqueur bottle, a container for a sextant (a navigational device), a human skull and bones [source: Thurman].

These findings have led to many groups to see Nikumaroro as the key to unlocking the mystery of the disappearance of Amelia Earhart. One of these groups, The International Group for Historic Aircraft Recovery (TIGHAR), has launched several investigations of the island and turned up some interesting finds. At an area on the island known as the Seven Site, something that appears to be a castaway camp was found. Giant clam shell fragments suggest a shell was smashed open. A cache of bones of turtles, fish and birds display evidence of having been exposed to fire. Also, the remains of woman's compact and a jar that once held a cream for lightening freckles, both from the 1930s were found. In the remains of the village on Gardener (which was left uninhabited once more in 1963 after a long drought), crafts made by residents out of aluminum aircraft metal were left behind [source: King].

The idea that Earhart's airplane broke up upon contact with the ocean and ended up used piecemeal for island handicrafts hasn't deterred some explorers from searching for the plane in the depths of the Pacific. Expeditions using sonar have focused on areas around Howland Island looking for the plane. But so far, neither the aircraft nor any pieces of it have been recovered. Why is that?

With so many pieces of evidence -- including human remains -- why does the mystery of Amelia Earhart remain unsolved?

Perhaps the biggest obstacle to discovery is the vast geographic area in which Earhart's plane might conceivably be found. No one can be certain exactly where Earhart's plane went down because of the loss of radio contact during the flight and the limiting effect of overcast skies on celestial navigation. Combing a quarter of a million square miles of ocean immediately following the disappearance yielded exactly nothing for the Navy. While subsequent efforts have focused on smaller areas, the searchable canvass remains massive, often on the order of 1,000 square miles (2,590 square kilometers).

The area's marine topography makes what's already a needle in a haystack job even more difficult: Pacific atolls rise up suddenly from the depths and are surrounded by steep shelves that lead to the ocean floor. Meanwhile, human error has also helped thwart the search for definitive proof. The human remains found on Gardner Island were lost after being examined by a doctor in the early 1940s. That rules out the definitive DNA matching technology that would likely determine conclusively whether the bones are Earhart's. (Forensic anthropologists looked at the doctor's notes in the 1990s and determined that the bones probably belonged to a woman of European descent) [source: Thurman].

These obstacles haven't deterred Earhart fans and aviation geeks from continuing their quest for answers. TIGHAR is set to launch a 30-day expedition in mid-September 2014 exploring the waters around Nikumaroro Island in an oceanographic research ship. Searchers plan to deploy two human-operated submersibles from the ship to capture detailed photo and video images of a 1-mile (1.6 kilometer) search area. At the same time, another team will comb the island's beachfront and forest in search of remnants from what might have been Earhart and Noonan's campsite [sources: Bennett-Smith, TIGHAR].

Searchers have continued to find significant clues. In 2013, TIGHAR announced that it had used sonar imaging to uncover evidence of a 22-foot (7-meter) object that may be a piece of Earhart's aircraft. Resting 600 feet (183 meters) below the surface of the Pacific Ocean and west of Nikumaroro, the image resembles the fuselage of Earhart's Lockheed Electra [source: Bennett-Smith].

There's good reason to believe that all or most of the plane remains intact. An hour before their last transmission, Earhart told the Coast Guard she and Noonan were flying at a low altitude, around 1,000 feet (304 meters). At around 100 miles per hour (161 kph), the Lockheed Electra could conceivably have maintained its integrity. If it did, the plane may still be in perfect shape, preserved in the oxygen-deprived depths of the South Pacific. Perhaps sooner rather than later we'll get to the bottom of the mystery surrounding Earhart's disappearance.