The Aeronautical Division, Signal Corps (1907–1914) was the first heavier-than-air military aviation organization in history and the progenitor of the United States Air Force. A component of the U.S. Army Signal Corps, the Aeronautical Division procured the first powered military aircraft in 1909, created schools to train its aviators, and initiated a rating system for pilot qualifications. It organized and deployed the first permanent American aviation unit, the 1st Aero Squadron, in 1913. The Aeronautical Division trained 51 officers and 2 enlisted men as pilots, and incurred 13 fatalities in air crashes. During this period, the Aeronautical Division had 29 factory-built aircraft in its inventory, built a 30th from spare parts, and leased a civilian airplane for a short period in 1911.