Pan American initiated trans-Pacific airmail service on 22 November 1935, and began carrying passengers in October 1936.

The last radio contact was 3 hours 27 minutes later, when the aircraft reported flying through layers of clouds and moderately rough air 565 miles (909 km) from the Philippine coast.

[3] The US Army transport ship USAT Meigs found an oil slick along the course of the lost aircraft about 500 miles (800 km) from Manila, took samples, and stood by to investigate.

[5] Modern reviews of the events and oil sampling techniques have led some to conclude the test of oil from the tropical Pacific compared to samples from San Francisco were not conclusive in ruling out a link with a slick found close to the last estimated position allowing for ocean currents.

It was the worst Pacific airline accident at the time, although fatalities were higher when the other two Martin M-130 flying boats crashed later.