The President of the United States of America, authorized by Act of Congress July 9, 1918, takes pride in presenting the Silver Star (Posthumously) to Sergeant William L. Hammack (ASN: 6983892), United States Army Air Forces, for gallantry in action against the enemy while serving as Flight Engineer of a B-17 Flying Fortress Bomber in the 26th Bombardment Squadron, 11th Bombardment Group (Heavy), Far East Air Force, in aerial operations over Tulagi in the Southwest Pacific Theater of Operations, on 4 August 1942. As part of a three-bomber formation, Sergeant Hammack, as a member of the crew of a plane in a three-bomber formation, proceeded on a mission to bomb enemy installations in the Tulagi area. As the flight approached the target it was attacked by seven float-type Zero fighters, the first of which was shot down. A second enemy fighter was hit heavily, broke into flams, and crashed into the bomber carrying Sergeant Hammack. It exploded and fell into the sea with the enemy plane, carrying with it the entire crew. The gallant actions and dedicated devotion to duty demonstrated by Sergeant Hammack, without regard for his own life, were in keeping with the highest traditions of military service and reflect great credit upon himself and the United States Army Air Forces.