Investigation was first a fleet search, then a legal death, then decades of private archaeology.
It is described here as what agencies and later groups did after the fact, not as a guide to a forced landing.
Agencies
- United States Coast Guard (Itasca) — Radio and fuel ship at Howland; keeper of the last-hour log.
- United States Navy — Led the July 1937 search with surface ships and Lexington aircraft; produced the working ditching conclusion.
- California courts — Issued the 1939 legal death that closed Putnam’s estate problem.
- TIGHAR and later private teams — Island and sonar campaigns that keep the file in public English without an official identification.
What followed
- Talk the aircraft in
Itasca’s assigned job on the morning of 2 July. Frequency and bearing problems meant the job failed in public.
- Open a multi-ship search
Navy and Coast Guard units ran boxes around Howland and along possible sun-line extensions.
- Check reefs and flare reports
Sightings were flown. None became NR16020.
- Close the estate
The 1939 court date ended the missing-person legal limbo without a body.
- Reopen on islands
Late-century private work on Nikumaroro treated the 157–337 line as a path, not only as a local search.
- Scan deep water
Twenty-first-century sonar near Howland looks for the official ditching. Candidates have not been certified.
Turning points
- Loss of two-way radio — Once Earhart could not hear Itasca, Howland became a visual needle. The log still recorded her voice.
- The 157–337 line — A navigation sentence that later authorised both a near-Howland ditching and a Phoenix Islands argument.
- The 1939 legal death — The state’s end of the person-file. The wreck-file stayed open.
The investigation found a radio line and failed to find an aircraft.
Public-record encyclopedia. Not legal advice. Not a how-to. Graphic detail is withheld. Wars belong in a separate atlas.