The experienced Japanese carrier aircrews performed better than those of the U.S., achieving greater results with an equivalent number of aircraft. The Japanese attack on the U.S. carriers on 8 May was better coordinated than the U.S. attack on the Japanese carriers. The Japanese suffered much higher losses to their carrier aircrews, losing ninety aircrew killed in the battle compared with thirty-five for the U.S. side. Japan's cadre of highly skilled carrier aircrews with which it began the war were, in effect, irreplaceable because of an institutionalised limitation in its training programs and the absence of a pool of experienced reserves or advanced training programs for new airmen. Coral Sea started a trend which resulted in the irreparable attrition of Japan's veteran carrier aircrews by the end of October 1942.