After the failure of the 1982 summer offensives, Iran believed that a major effort along the entire breadth of the front would yield victory. During the course of 1983, the Iranians launched five major assaults along the front, though none achieved substantial success, as the Iranians staged more massive "human wave" attacks. By this time, it was estimated that no more than 70 Iranian fighter aircraft were still operational at any given time; Iran had its own helicopter repair facilities, left over from before the revolution, and thus often used helicopters for close air support. Iranian fighter pilots had superior training compared to their Iraqi counterparts (as most had received training from US officers before the 1979 revolution) and would continue to dominate in combat. However, aircraft shortages, the size of defended territory/airspace, and American intelligence supplied to Iraq allowed the Iraqis to exploit gaps in Iranian airspace. Iraqi air campaigns met little opposition, striking over half of Iran, as the Iraqis were able to gain air superiority towards the end of the war.