NavList:

But it doesn't matter who gets credit for inventing the "single line of position landfall " proceedure (as it is called in Air Force manuals) the point is, in the Earhart context, is that it has proven to be a reliable way to find islands, so reliable, in fact, that military flight navigators must know it and civilian fllght navigators are required to  demonstrate it on the FAA Flight Navigator flight test. There is no doubt that Noonan could have navigated that proceedure and arrived at Howland had the plane entered the area that was clear of clouds.

gl