At 03:30 local time on 8 December 1941 (about 09:00 on 7 December in Hawaii), Sutherland learned of the attack on Pearl Harbor and informed MacArthur. At 05:30, the Chief of Staff of the U.S. Army, General George Marshall, ordered MacArthur to execute the existing war plan, Rainbow Five. MacArthur did nothing. On three occasions, the commander of the Far East Air Force, Major General Lewis H. Brereton, requested permission to attack Japanese bases in Formosa, in accordance with prewar intentions, but was denied by Sutherland. Not until 11:00 did Brereton speak with MacArthur about it, and obtained permission. MacArthur later denied having the conversation. At 12:30, nine hours after the attack on Pearl Harbor, aircraft of Japan's 11th Air Fleet achieved complete tactical surprise when they attacked Clark Field and the nearby fighter base at Iba Field, and destroyed or disabled 18 of Far East Air Force's 35 B-17s, 53 of its 107 P-40s, three P-35s, and more than 25 other aircraft. Most were destroyed on the ground. Substantial damage was done to the bases, and casualties totaled 80 killed and 150 wounded. What was left of the Far East Air Force was all but destroyed over the next few days.