On 17 April, "Chicago" was ordered to proceed to the Sea of Japan, off Korea, for duty with Task Force 71. In response to the shooting down of an EC-121 by North Korean fighters on 14 April, that killed all 31 personnel on board, the Task Force patrolled the Sea of Japan during the crisis that followed. The cruiser provided PIRAZ and screening duties for the carriers, and their constant air patrols, until 27 April when the ship departed for upkeep at Sasebo, Japan.