I read a really interesting book years ago about Earhart and the various trips she made.
IIRC the navigator was relatively new, and something about the radio had changed that neither was experienced with. It could be switched from voice or to just morse code (or maybe not morse code but some sort of beacon). There were pros and cons with each, so they would use voice on the hour, and the beacon on the half hour. It was critical when they approached Howland Island. They would know when they were near the longitude of the island based on their speed, but not their latitude. To get that they would head south and note the strength of the radio signal. If it got stronger they kept going. If it got weaker they would turn north.
But - there were problems with the radio on shore for one of the transmissions so they used a ship in the harbor that was from Hawaii.
The book theory was that the plane’s radio switch may have either been in the wrong position at the critical times, and/or the times were not in sync between the plane, land or ship. My memory is foggy, but the plane was supposed to use the time from it’s last departure as a reference. IIRC Howland Island was something like 4 hours different but the on the hour and the half-hour would have still been constant.
BUT - the navy ship was on Hawaii time, which was something like 6 1/2 hours off! So when Earhart was listening for a voice radio, they were transmitting the beacon and vice versa!
As is typical with most accidents, they are due to cascading failures.
Based upon the investigation of Earhart’s missing, they changed things so everyone (planes, ships, ports, etc.) to Greanwich Mean Time so every one would be on the same time.
originaly the round the world flight was to fly to hawaii first, there was a crash in oakland in 1936, so the plane was returned to burbank and repaired at lockheed. as an aside my grandfather and great grandfather worked at lockheed. my father who was 8 at the time and his sister who was 14 at the time got to go on a flight with Earhart, their instructions were to never repeat a work she spoke, AE swore like a longshoreman..
in 1937 the round the world flight continued except the flew east and the rest is history.