Almost immediately after the completion of the St. Mihiel offensive that the group began preparing for a drive in the Verdun area. On the night of 25 September, the heaviest American artillery barrage of the war was laid down on the enemy front. Operations orders received stated that all available aircraft would leave the ground before dawn to attack and destroy all enemy observation balloons. After that aircraft would attack enemy troops on the ground and engage any enemy aircraft to prevent them attacking friendly infantry forces.