Charles Sweeney
Poor bombing visibility and an increasingly critical fuel shortage eventually forced "Bockscar" to divert from Kokura and attack the secondary target, Nagasaki. As they approached Nagasaki, the heart of the city's downtown was covered by dense cloud, and Sweeney and the plane's weaponeer, Commander Ashworth, initially decided to bomb Nagasaki using radar. However, a small opening in the clouds allowed "Bockscar's" bombardier to verify the target as Nagasaki. As the crew had been ordered to drop the bomb visually if possible, Sweeney decided to proceed with a visual bomb run. "Bockscar" then dropped "Fat Man", with a blast yield equivalent to 21 kilotons of TNT. It exploded 43 seconds later at above the ground, at least northwest of the planned aim point. The failure to drop "Fat Man" at the precise bomb aim point caused the atomic blast to be confined to the Urakami Valley. As a consequence, a major portion of the city was protected by the intervening hills, and only 60% of Nagasaki was destroyed. The bombing also severed the Mitsubishi arms production extensively and killed an estimated 35,000-40,000 people outright, including 23,200-28,200 Japanese industrial workers, 2,000 Korean slave laborers, and 150 Japanese soldiers.
Enola Gay
The Hiroshima mission was followed by another atomic strike. Originally scheduled for 11 August, it was brought forward by two days to 9 August owing to a forecast of bad weather. This time, a Fat Man nuclear weapon was carried by B-29 "Bockscar", piloted by Major Charles W. Sweeney. "Enola Gay", flown by Captain George Marquardt's Crew B-10, was the weather reconnaissance aircraft for Kokura, the primary target. "Enola Gay" reported clear skies over Kokura, but by the time "Bockscar" arrived, the city was obscured by smoke from fires from the conventional bombing of Yahata by 224 B-29s the day before. After three unsuccessful passes, "Bockscar" diverted to its secondary target, Nagasaki, where it dropped its bomb. In contrast to the Hiroshima mission, the Nagasaki mission has been described as tactically botched, although the mission did meet its objectives. The crew encountered a number of problems in execution, and had very little fuel by the time they landed at the emergency backup landing site Yontan Airfield on Okinawa.