Amelia Earhart (1897-1937) had become the most famous female aviator in the world after her 1932 solo transatlantic flight — the second person and the first woman to make the crossing. By 1937 she was 39, had flown dozens of pioneering routes, and had published two best-selling memoirs.
Her 1937 project was a round-the-world flight along the longest possible route: an equatorial circumnavigation of approximately 47,000 km. The route had never been attempted. The aircraft was a twin-engine Lockheed Electra 10E that her husband George Putnam had funded through public subscriptions and Purdue University research support.
She departed Miami on 1 June 1937 with navigator Fred Noonan, a former Pan Am Pacific clipper navigator with extensive ocean-crossing experience. The flight had crossed South America, the South Atlantic, central Africa, the Arabian Peninsula, India, and Southeast Asia by 29 June 1937. They reached Lae, Papua New Guinea, the penultimate scheduled stop, with approximately 11,000 km of flight remaining.
2 July 1937
The Lae-to-Howland-Island leg was the longest single overwater stretch of the entire flight: approximately 4,113 km (2,556 miles) of open Pacific to a 1.8-square-kilometre uninhabited coral atoll. The Howland Island target was a low atoll barely 8 metres above sea level. The US Navy had constructed an emergency landing strip on the island specifically for the Earhart flight and had stationed the Coast Guard cutter Itasca offshore as a radio direction-finding station.
Earhart and Noonan departed Lae at 0000 GMT on 2 July 1937. The planned flight time was approximately 18 hours.
The Itasca received radio messages from Earhart across the 17th and 18th hours of the flight. The messages indicated increasing concern about the position fix. The last clearly received transmission, at 20:14 GMT, said:
We are on the line 157 337. We will repeat this message. We will repeat this on 6210 kilocycles. Wait. We are running on line north and south.
The transmission indicates that Earhart and Noonan had executed a standard “line of position” search procedure — flying north and south along a line through Howland — but had not visually located the island. After 20:14 GMT no further transmissions were received.
The Electra’s fuel was calculated to have exhausted between 20:30 and 21:30 GMT.
The search
The US Navy and Coast Guard conducted the largest naval search in American history to that point. Nine ships (including the battleship Colorado and the aircraft carrier Lexington) and approximately 60 aircraft searched approximately 250,000 square miles of central Pacific across 2-18 July 1937.
They found nothing. The official Navy report concluded that the Electra had run out of fuel and crashed into the Pacific within visual range of Howland Island.
The alternative hypotheses
The subsequent 90 years have produced approximately five major competing reconstructions:
— Crashed and sank near Howland — the Navy’s official conclusion. The 1999 Elgen Long book argued the position specifically and predicted that the wreck lies on the Pacific floor at 5,200-metre depth approximately 35 nautical miles northwest of Howland. The 2002 Nauticos expedition failed to locate the wreck at that position but the search area was enormous and the wreck could still be there.
— Nikumaroro hypothesis — advocated by the TIGHAR (The International Group for Historic Aircraft Recovery) organisation since the 1980s. The argument: Earhart turned south after failing to find Howland, landed on the coral reef of Nikumaroro (then called Gardner Island, approximately 350 nautical miles southeast of Howland), and survived for days or weeks before dying of dehydration and exposure. The TIGHAR expeditions since 1988 have recovered some 1930s-era artefacts on the island, including a sextant box, cosmetic jars, and bones (the 1940 Burns measurements of the bones have been reanalysed by Richard Jantz in 2018 as consistent with Earhart’s measurements). The Nikumaroro hypothesis is the most-cited alternative but has not been conclusively proved.
— Japanese capture — the conspiracy theory that Earhart and Noonan landed in Japanese-controlled Marshall Islands waters and were captured and executed as American spies. The documentary basis is thin; the photograph that History Channel aired in 2017 as showing Earhart in Japanese custody was debunked within 24 hours as having been published in a 1935 Japanese travel book — two years before the disappearance.
— Soviet capture, suicide, post-war identity changes — assorted late-20th-century theories without documentary support.