Resuming her operations in Vietnamese waters on 22 March, "William H. Standley" began a "difficult and demanding line period." Tensions in Korea had erupted, causing the U.S. naval forces in the Far East to go on alert. North Korean and U.S. forces had exchanged fire briefly near the demilitarized zone between the two Koreas on 11 March, and, on 15 April, North Korean fighters downed an EC-121 reconnaissance plane over international waters in the Sea of Japan. The plane, based at Naval Air Facility Atsugi, Japan, crashed with 31 men on board.