By the time Vincent V. Loomis is through, there seems little mystery about what happened to Amelia Earhart when she, her navigator and their plane disappeared over the Pacific Ocean in July 1937, setting off decades of speculation and spawning a small industry of crackpot theories.

Earhart, the most famous woman pilot of her time and perhaps any other, was trying to nail down her place in aviation history with an around-the-world flight in her twin-engine Lockheed Electra (not to be confused with the later passenger transport of the same name).

A U.S. Navy vessel had been dispatched to provide navigational assistance that would guide her to Howland Island on a long flight from Lae, New Guinea. Despite periodic radio contact with the ship, Earhart never arrived, and the strain of flying for more than 20 hours without sleep could be clearly heard in her voice.

The words of her last transmission were reported time and again in the world's press. They came at 8:44 a.m. on July 2 when she gave her position, announced what frequency she was monitoring and said, "We are running north and south."

Loomis, a retired Air Force officer who caught "Earhart fever" and traveled several times to the Pacific to try to sort through the mystery, makes a convincing presentation that he has solved it.

In the first place, he establishes the type of setting in which airplane accidents typically happen: a series of mistakes, big and little, any one of which might be survivable. Taken together, they are deadly.

Loomis establishes that Earhart was a by-the-book pilot who didn't always make sure the book was completed before taking off. She never learned to navigate and had an appalling habit of flying with alcoholics.

Her navigator, Frederick Noonan, had been fired by Pan American World Airways for spending too much time with the bottle, and in one of her last phone conversations with her husband, promoter George Putnam, Earhart said of Noonan, "He's hitting the bottle again and I don't even know where he's getting it."

Earhart never learned to use a telegraph key, and radio navigation in the 1930s, particularly over the trackless Pacific, virtually demanded a reliance on telegraph instead of voice for primary direction-finding. Pan Am offered its radio net to Earhart, but she declined.

So Earhart was trying to hit a small piece of rock in the middle of the ocean with a drunken navigator, little knowledge of navigation, and inadequate radios. Little more is needed to explain why she got lost.

Since Earhart, Noonan and the Electra were never found, it was easy to construct all kinds of explanations for what happened. Loomis claims to have found, and quotes by name, witnesses who said they had seen the plane come down on a coral reef in the Marshall Islands, then a Japanese protectorate.

Earhart and Noonan were taken captive by the Japanese and transferred to Saipan, where they died in prison, according to more witnesses quoted by Loomis. He theorizes that the two had seen too much of Japan's pre-World War II military buildup in the Marshalls to be set free.

Interviews and Japanese documents examined by Loomis show that, while Japan assured the United States it was searching its section of the Pacific for the plane's wreckage, in fact no search was under way.

For Loomis' work to be credible, there has to be an explanation of how the Earhart plane came to be in the Marshalls, more than 150 miles off course from Howland Island. Loomis relies heavily on the work of a retired Pan Am navigator, Paul Rafford Jr., who is familiar with the territory, the navigational procedures and the radios of the time. Rafford has constructed a thoroughly plausible answer, given Earhart's radio capability and assuming an intentional change of course she made to compensate for her incapacitated navigator. One jarring note in this book is the displaced first chapter, which recounts the last flight itself and seems to have been pulled out of chronological order and placed in the front without enough editing to provide the information needed for comprehension.

It's tough going and could discourage exploration of the fine work that follows.