Hawaii Clipper disappears between Guam and Manila as the first loss of an airliner in trans-Pacific China Clipper service.

Pan Am Flight 229 was a regularly scheduled passenger flight operated by Pan Am's Martin M-130 flying boats from San Francisco to Manila, which on July 28 1938, disappeared after flying over the Pacific Ocean. The flight was operated by Hawaii Clipper, one of the three Pan American Martin M-130 flying boats. It disappeared with six passengers and nine crew.

Guam is an island that is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, and the most populous village is Dededo. It is the westernmost point and territory of the United States, as measured from the geographic center of the U.S. In Oceania, Guam is the largest and southernmost of the Mariana Islands and the largest island in Micronesia. In 2022, its population was 168,801. Chamorros are its largest ethnic group, but a minority on the multiethnic island. The territory spans 210 square miles and has a population density of 775 per square mile (299/km²).

Manila, officially the City of Manila, is the capital and second-most populous city of the Philippines after Quezon City, with a population of 1,902,590 people in 2024. Located on the eastern shore of Manila Bay on the island of Luzon, it is classified as a highly urbanized city. With 43,611.5 inhabitants per square kilometer (112,953/sq mi), Manila is one of the world's most densely populated cities proper.

China Clipper (NC14716) was the first of three Martin M-130 four-engine flying boats built for Pan American Airways and was used to inaugurate the first commercial transpacific airmail service from San Francisco to Manila on November 22, 1935. Built at a cost of $417,000 by the Glenn L. Martin Company in Baltimore, Maryland, it was delivered to Pan Am on October 9, 1935. It was one of the largest airplanes of its time.