While living in Los Angeles in 1923, Earhart worked in a photography studio; she and a friend later briefly operated their own photography business. This interest endured; Earhart took a number of photographs of clouds and ships that passed below as the Friendship crossed the Atlantic in 1928 and she continued to take pictures of the people and places she visited. These pictures from 1937, along with diary entries that she was writing for the book about her flight, were mailed back to Putnam in the United States.
Author Randall Brink interviewed a Lockheed technician, who told him: "I recall that I was directed to cut two 16-to-18-inch-diameter holes for the cameras, which were to be mounted in the lower aft fuselage bay and would be electrically operated." These cameras, Mr. Brink says, were placed there to take pictures of Japan's military buildup in the islands.
Japan seized the islands from the Germans during World War I (1914). The League of Nations awarded a mandate to the Japanese after the War under the authority of Article 22 of the League of Nations Charter. The Japanese set up their administration at Jaluit which had been the German administrative center. The Marshalls were referred to as the Eastern Mandates. The Japanese after World War I settled about 1,000 Japanese civilians on the Marshalls in addition to military personnel. As Japan began to move toward war (late-1930s), they began to militarize the islands with the idea of expansionism south and toward other islands in Oceania. This was a violation of the League of Nations Mandate under which the islands had been administered, but Japan had withdrawn from the League (1934). The Japanese had, however, on at least one of the islands in the major atoll group built airstrips for military aircraft.
Very soon after seizing the islands in 1914, Japan placed serious restrictions on visits there by ships of other nations. Concern on the part of Britain and the U.S. over this development – both because it restricted trade by their merchants and because it could permit the Japanese to fortify the islands in secret – may have led the U.S. to instigate a diplomatic conflict over a cable relay station on Yap in 1921. In settling its dispute with the U.S. over this station Japan in 1922 agreed to unrestricted access to Micronesian territorial waters by U.S. commercial vessels, and to the extension of an existing free trade agreement, the Treaty of Commerce and Navigation, to the mandated islands. However, Port visits could be carried out only in accordance with complex regulations, so complex and restrictive, that they had the effect of excluding foreign shipping. These regulations and their implementation served to keep other nations in the dark about just what the Empire was up to in its mandated islands. The result was suspicion on the part of nations like the U.S., which initiated intelligence operations to find out what was going on. Between 1915 and 1922, most intelligence work involved interviewing people who had traveled to or through the islands for commercial or other reasons. The period from 1922 through 1929 saw the active if not always very effective use of spies operating under cover of commercial and scientific activities. The third, during the 1930s and 1940-41, emphasized monitoring radio transmissions, censoring mails, the continuing use of agents and aerial overflights.
Two major questions have been raised: First, would the U.S. have had any reason to organize such a spy mission, and second, would the Japanese, had they discovered it, have had any reason to keep the matter secret and execute the spies?
By 1937 the Imperial Japanese Navy was calling the shots in Micronesia and initiated construction of major improvements in air, sea and land facilities. Sea-plane facilities had already been built for the Nan'yõ-Cho (South Seas Government) in the late 1930s on several islands of the former Mandated Territory and between 1935 and 1937 the Japanese government spent almost 1,000,000 Yen on further construction of air facilities. In the Marshall Islands, known seaplane bases with shore facilities were located on Wotje, Wotje Atoll; Ebeye, Kwajalein Atoll; Jabwor, Jaluit Atoll; Djarrit, Majuro Atoll; and Engebi, Enewetak Atoll. Suspected seaplane facilities or temporary seaplane bases may have existed on Rongelap, Mile and Bokak. Certainly the U.S. was suspicious of Japanese intentions in the islands, and its suspicions had to be heightened by Japan's withdrawal from the League of Nations and its abrogation of the naval treaties. Certainly, too, the U.S. was actively involved in gathering intelligence about what the Japanese were doing in the mandate.
Under these circumstances it is not unreasonable to think that U.S. intelligence would have been interested in having someone fly over key islands in the mandate. Before and during World War II, Truk Lagoon was Japan's main base in the South Pacific theatre, a heavily fortified base for Japanese operations against Allied forces in New Guinea and the Solomon Islands, serving as the forward anchorage for the Japanese Imperial Fleet.
In 1937, U.S. intelligence would have been extremely interested in the status of this naval base, once known to Allied forces as Japan's "Gibraltar of the Pacific," and Amelia might have been asked to observe and possibly even take some photos. If the Electra had turned NE from New Guinea it would have arrived over Truk at about 7 p.m. local time, with plenty of daylight left. Now I fully understand that we have no proof that Amelia attempted to perform such a mission, but her actions during the final flight suggest something very strange was afoot, and she had two meetings with top U.S. officials during April 1937, according to Margot DeCarie, her personal secretary.
So after leaving New Guinea, Amelia could have turned NE aiming for Truk, overfly Truk and the rest of that island group and the turn SE to aim for Howland. Earhart's final in-flight radio message occurred at 08:43: "We are on the line 157-337. We will repeat this message. We will repeat this on 6210 kilocycles. Wait," she said. 157/337 is a compass heading from the north to the south and would intersect a line drawn straight East from Truk. So after flying East from Truk, Earhart could then turn South along this heading to hit Howland.
Now before you all jump in here, once again I do understand that there is an alternative explanation: Noonan, unable to take celestial bearings during the night due to cloudy conditions would have used the time of sunrise to determine his East-West position. The sun rises in a slightly different direction every day, and it climbs at an angle so the direction is constantly shifting. That morning it came up at 67 degrees, and because a Line of Position is always at a right angle to the observed celestial body, the line to be derived from the rising sun was 157/337. By noting the time that the sun came up, Amelia's navigator, Fred Noonan, could draw a 157/337 line on his map and know that they were somewhere on that line. He can then draw a 157/337 line that passes through Howland. The distance between those two parallel lines tells then how far they have to fly East to hit the second 157/337 line. The problem is now that they have no way of knowing their North or South distance from Howland. They now have to visually sight Howland. At the time an Excellent navigator would get +/- 5 miles from their destinations by this DR method and +/- 10 miles was an acceptable error. However this included being able to take bearings during the flight to correct for North/South drift.
One can only guess what Earhart might have seen/photographed over Truk. Had Amelia Earhart flown over any of the Marianas or Carolines ... she would have seen only the same sort of facilities available to Pan-American Airways at its new commercial base at Guam; had she flown over the Marshalls ... she might have seen Japanese warships at Jaluit Atoll and possibly the construction of new facilities such as the new Japanese airbase on Taroa Island
But of course, what Earhart and Noonan actually saw or could have seen, whether they were or were not spies is not really relevant. No one who has worked in a bureaucracy can have much trouble imagining a situation in which someone makes a stupid mistake – a local military official or police official overreacts to the crash landing of what he thinks is a spy plane – and things spiral out of control, to the point at which there is nothing to do but execute the supposed spies and hide the evidence that it ever happened to "save face" and remember that by this point in time the Japanese military, even lower ranking officers were making the decisions not Tokyo.
Again I point out the Shenyang/Mukden incident that triggered the Japanese invasion of Manchuria. Three Colonels and a Major, Colonel Seishirō Itagaki, Lieutenant Colonel Kanji Ishiwara, Colonel Kenji Doihara, and Major Takayoshi Tanaka had laid complete plans for the incident by May 31, 1931.
At Dalian in the Kwantung Leased Territory, Commander-in-Chief of the Kwantung Army General Shigeru Honjō was at first appalled that the invasion plan was enacted without his permission, but he was eventually convinced by Ishiwara to give his approval after the fact.
The Japanese invasion of China itself was triggered by a Japanese private. When a Japanese soldier, Private Shimura Kikujiro, failed to return to his post, Chinese regimental commander Ji Xingwen (219th Regiment, 37th Division, 29th Route Army) received a message from the Japanese demanding permission to enter Wanping to search for the missing soldier. The Chinese refused. And, although Private Shimura returned to his unit, by this point both sides were mobilizing, with the Japanese deploying reinforcements and surrounding Wanping. A Truce was eventually negotiated but again a Japanese Garrison Infantry Brigade commander General Masakazu Kawabe rejected the truce and, against his superiors' orders, continued to shell Wanping for the next three hours, until prevailed upon to cease and to move his forces to the northeast.
The question of whether Earhart and Noonan ditched in the sea and sank or made a landing is also open to question.
Transmissions from Earhart's Electra (NR16020) were possible on three primary frequencies: 3105 kHz, 6210 kHz and 500 kHz. For the latter, however, there were no reported post loss signals.
On her world flight, Earhart transmitted on 3105 kHz at night, and 6210 kHz during daylight, using her 50-watt WE-13C transmitter.
The Itasca transmitted on 3105 kHz, but did not have voice capability on 6210 kHz.
Under favorable propagation conditions, it was possible for aircraft operating on the U.S. West Coast at night to be heard on 3105 kHz in the central Pacific. In fact, the Itasca reported hearing such signals on one occasion. TIGHAR built a detailed catalog and analysis of all the reported post-loss radio signals, and selected the credible ones based on those frequencies. Amelia Earhart did not simply vanish on July 2, 1937. Radio distress calls believed to have been sent from the missing plane dominated the headlines and drove much of the U.S. Coast Guard and Navy search. When the search failed, all of the reported post-loss radio signals were categorically dismissed as bogus.
Using digitized information management systems, antenna modeling software, and radio wave propagation analysis programs, TIGHAR re-examined all the 120 known reports of radio signals suspected or alleged to have been sent from the Earhart aircraft after local noon on July 2, 1937 through July 18, 1937, when the official search ended. They concluded that 57 out of the 120 reported signals are credible.
The results of the study suggest that the aircraft was on land and on its wheels for several days following the disappearance since a plane under water could not transmit. Since these were open broadcasts they certainly could have been heard by the Japanese who then located and captured the pair.