which was a significant factor in his future leadership in the industry.

In his early years at GE, Hal contributed to studies of the stability of electric power systems and brought some of the lessons from this work into the classrooms of the Advanced Engineering Program. From the middle of World War II to the mid-1950s, working in the GE Aeronautics and Ordnance Department, he contributed to the design and development of various fire-control, aircraft, and guided-missile systems. He later managed the Systems Engineering and Analysis Branch of the GE Advanced Technology Laboratory, which eventually merged into the GE Corporate Research and Development Laboratory in Schenectady, where he was responsible for aspects of automatic control and information systems on many projects, including rapid transit and the Apollo mission.

Hal was always interested in communication among professionals, and he ultimately achieved the top leadership roles in two major professional technical societies. After the success of Servomechanisms, he was one of the best-known American personalities in the field of control engineering, and in 1957, when the International Federation of Automatic Control (IFAC) was founded, Hal was elected its first president.

IFAC was founded during the cold war, and the organizers were faced with choosing a Russian or an American for president. Although Hal was not a member of the provisional committee that founded IFAC, Rufus Oldenberger, a professor of mechanical engineering at Purdue University who led the American “delegation,” argued that Hal was the best person for the job. Although it had been agreed that the biannual (later triennial) World Congresses of IFAC would be held in the home country of the president, in light of cold war realities, a decision was made that an American would be the first president but the first World Congress would be held in Moscow. So although the first president, Hal, was an American, the second president, Alexander Letov, a Russian, presided over the first IFAC World Congress in Moscow in 1960.

In the 1950s and 1960s, Chestnut took on leadership roles in the American Institute of Electrical Engineers (AIEE)