Today the Federal Aviation Administration announced the list of air traffic control towers to be closed as the agency implements its sequestration budget cuts. The March 22 press release notes that the FAA originally planned to close 189 towers, but reduced the number to 149 in the final plan.

The reduction in the number of towers to close was due in part to the decision that keeping some towers open was in the national interest. Twenty-four federal contract towers that are staffed by private contractors that were slated to close will remain open. Additionally, 16 contract towers that are part of a cost sharing program will remain open because Congress appropriates their operating funds directly. These towers will have their funds reduced by five percent, but this will not force their closure.

The list of tower closures (which can be viewed here) is made up primarily of general aviation reliever airports so airline travel will be minimally affected by the closures. There are several towers in secondary airline markets that slated to be closed, however. Among these are Columbia, S.C, Concord, N.H., Santa Fe, N.M., and Pocatello, Idaho.

Several towers at Georgia airports are among those on the closure list as well. Two Atlanta-area airports, Cobb County-McCollum Field and Gwinnett County – Briscoe Field, will lose their control towers. Additionally, three other towers around the state, Southwest Georgia Regional in Albany, Middle Georgia Regional in Macon, and Athens – Ben Epps will close. The tower at Fulton County – Brown Field in Atlanta was slated to close, but will remain open.

The fact that control towers are being closed does not mean that airline flights will cease or that the airport itself will close. Instead, it means that the airport will become a “nontowered” airport where pilots revert to “see-and-avoid” procedures and enter the flow of traffic themselves rather than having an air traffic controller regulate the flow of takeoffs and landings.

While pilots fly from nontowered airports, there might be slight delays to obtain a clearance to take off and enter the enroute system. Tower closures might result in radar gaps around these airports that require controllers to leave more space between aircraft. The absence of tower controllers might also mean that weather minimums for instrument approaches at some airports increase due to the lack of weather observers. This could mean delays or diversion of flights during periods of bad weather.

Many of the towers that will be closed were already operating on a part time basis. Control towers at smaller airports are often open only during the day or at peak hours.

In addition to the list of towers that will be closed, the FAA also published a list of contract towers that will remain open as well as list of contract cost share towers that will remain open.