early 20th century. A succession of accidents during the pre-war exhibition era (1910–16) and barnstorming decade of the 1920s gave way to early forms of federal regulation intended to instill public confidence in the safety of air transportation. As claimed by the Aircraft Year Book, barnstormers caused 66% of fatal accidents during 1924. Opponents of this view included those who distrusted government interference or wished to leave any such regulation to state authorities. Barnstorming accidents that led to such regulations during this period are accurately depicted in the 1975 film The Great Waldo Pepper. At the urging of the aviation industry, that believed the airplane could not reach its full commercial potential without federal action to improve and maintain safety standards, President Calvin Coolidge appointed a board to investigate the issue. The board's report favored federal safety regulation. To that end, the Air Commerce Act became law on May 20, 1926. The Act created an Aeronautic Branch assigned to the United States Department of Commerce, and vested that entity with regulatory powers to ensure a degree of civil air safety. Among these powers were: testing and licensing pilots, issuing certificates to guarantee the airworthiness of aircraft, making and enforcing safety rules, certificating aircraft, establishing airways, operating and maintaining aids to air navigation, and investigating accidents and incidents in aviation. The first head of the Branch was William P. MacCracken, Jr. High visibility accidents such as the 1931 Transcontinental & Western Air Fokker F-10 crash and the 1935 crash of TWA Flight 6 continued to make headlines. In fulfilling its civil aviation responsibilities, the Department of Commerce initially concentrated on functions such as safety rulemaking and the certification of pilots and aircraft. It took over the building and operation of the nation's system of lighted airways, a task begun by the Post Office Department. The Department of Commerce improved aeronautical radio communications, and introduced radio beacons as an effective aid to air navigation. In 1934, the Aeronautics Branch was renamed the Bureau of Air Commerce. As commercial aviation grew, the Bureau encouraged airlines to establish three centers (Newark, New Jersey; Cleveland, Ohio; and Chicago, Illinois) to provide air traffic control in airways. In 1936, the Bureau itself took over the centers and began to expand the ATC system. Pioneer air traffic controllers resorted to using maps, blackboards, and calculations to perform their new roles, making sure aircraft traveling along designated routes