April, Spruance ordered Task Force 54, which consisted mostly of modernized Standard-type battleships under the command of Rear Admiral Morton Deyo (which were engaged in shore bombardment), to intercept and destroy the Japanese sortie. Deyo moved to execute his orders, but Vice Admiral Marc A. Mitscher, who commanded Task Force 58, preempted Spruance and Deyo by launching a massive air strike from his carriers, without informing Spruance until after the launches were completed. As a senior naval aviation officer, "Mitscher had spent a career fighting the battleship admirals who had steered the navy’s thinking for most of the current century. One of those was his immediate superior, Raymond Spruance. Mitscher felt a stirring of battleship versus aircraft carrier rivalry. Though the carriers had mostly fought the great battles of the Pacific, whether air power alone could prevail over a surface force had not been proven beyond all doubt. Here was an opportunity to end the debate forever". Around 10:00 on 7 April, Task Groups 58.1 and 58.3 began launching 280 aircraft from their carriers to attack the Japanese force. Task Group 58.4 launched a further 106 aircraft. The aircraft consisted of F6F Hellcat and F4U Corsair fighters, SB2C Helldiver dive bombers, and TBF Avenger torpedo bombers. Overall, 15 carriers launched aircraft. The air groups launched from five carriers became lost in bad weather and were not able to attack. As a contingency, Spruance ordered Admiral Deyo to assemble a force of six fast battleships, seven cruisers and 21 destroyers to prepare for a surface engagement with Yamato should the airstrikes prove unsuccessful. Battle Around noon, the first American aircraft arrived over Yamato; these were F6F Hellcat and F4U Corsair fighters, under orders to deal with any Japanese aircraft that might appear to defend the below-mentioned ships, but none appeared. Once it became obvious that the Japanese force had no air cover, the U.S. aircraft could set up for their attacks without fear of opposition from Japanese aircraft. U.S. bomber and torpedo aircraft arriving over the Yamato group—after their two-hour flight from Okinawa— could circle the Japanese ship formation just out of anti-aircraft range to set up their attacks on the warships below methodically. The first wave of U.S. carrier planes was spotted by a Japanese lookout on the bridge at 12:32. Two minutes later, at 12:34, Yamato opened fire with her 460 mm main batteries. The Japanese ships stopped zigzagging