The Federal Aviation Administration named a top former U.S. Air Force general as its new assistant administrator for NextGen, the agency’s ambitious and costly program to modernize the nation’s ATC system.

This week, FAA Administrator Michael Huerta informed employees of the appointment of Maj. Gen. Edward Bolton to the position of NextGen assistant administrator, which had been filled by an interim administrator since Victoria Cox retired earlier this year. Bolton previously served as deputy assistant secretary for budget with the office of the assistant secretary of the Air Force for financial management. As recently as this spring, he represented the Air Force during Pentagon briefings on the Department of Defense’s Fiscal Year 2014 budget submission.

Bolton formerly commanded the 45th Space Wing and directed the Eastern Range at Patrick Air Force Base, Fla., which supports missile and rocket launches from Cape Canaveral Air Force Station and the Kennedy Space Center. He will start with the FAA on September 9.

The FAA’s appointment of Bolton fills another important vacancy in the $40 billion NextGen effort, which has been challenged by “organizational weaknesses” and frequent turnover in leadership, according to the Department of Transportation inspector general’s office. In May, the White House announced the appointment of  former United Airlines and TWA executive Michael Whitaker as the FAA’s new deputy administrator, its second-ranking position, and “chief NextGen officer.” FAA administrator Michael Huerta originally held that title when he joined the agency in 2010. However, David Grizzle, Air Traffic Organization chief operating officer, has announced that he will retire from the FAA in December.

Cox, trained as a physicist, served as director of international technology programs in the Pentagon’s Office of the Director of Defense Research and Engineering before joining the FAA. She represented the NextGen effort before Congress and at numerous industry gatherings.

In a blog post in February, former FAA deputy administrator Joseph Del Balzo, now president of JDA Aviation Technology Solutions, described Cox’s retirement as “a major blow” to the NextGen effort. “The job of designing and implementing NextGen is a virtually impossible task,” Del Balzo wrote. “Identifying and integrating state-of-art technologies, creating a totally new navigation infrastructure, designing the computers and scopes which will facilitate a totally new concept of air traffic management…buying new hardware and software that will deliver the safety benefits promised and doing all of that within budget and on schedule describes a mission not seen since Sisyphus. Ms. Cox did an excellent job on all of those technical assignments.”