The Federal Aviation Administration is planning to move ahead with closing 173 air traffic control towers at the beginning of April, including 13 in New England, although the agency is giving aviation authorities a chance to make a case for keeping their facilities open.

The closures, part of the FAA’s plan to slash its budget by $600 million as part of the forced federal spending cuts known as sequestration, could remove controllers from six towers in Massachusetts, six in Connecticut, and one in New Hampshire. The airports would remain open, but instead of relying on controllers for clearance to take off and land, pilots would communicate their position on an airport radio frequency.