General aviation groups are bracing for the ramifications of the looming closure of air traffic control towers at nearly 240 airports, loss of upkeep of navigational aids (navaids) at many of those airports and a reduction in controller staff as FAA implements rolling furloughs.

But as sequestration officially took effect March 1, confusion still existed on what exactly would be affected and when.

FAA’s share of the sequestration cuts for the remainder of fiscal 2013 would be $600 million – accounting for 60% of the Department of Transportation’s total sequester cuts. This is a disproportionate share, since FAA makes up only about 20% of DOT’s budget. But FAA Administrator Michael Huerta told Congress last week that’s because “a very large portion of the DOT’s budget is exempt from the sequester.”

Not only does the sequester mandate the protection of most of DOT’s budget, it also shelters a great portion of FAA’s budget, including airport grants, most facilities and equipment and some research, engineering and development. This leaves FAA’s operations account vulnerable to most of the sequester cuts.

FAA told stakeholders last week that the agency was evaluating options, but indicated a large number of towers would close, while many others would be shut during nighttime hours. Questions remained on which towers and when.

FAA initially indicated that the closures would potentially affect 100 towers, but the number has grown to close to 240 – the vast majority of which are contract towers. Contract towers are slated to close first, as soon as April, while federally-run towers on the closure list may stay open until September, says Heidi Williams, vice president of air traffic services and modernization for the Aircraft Owners and Pilots Association (AOPA).

But in a blog post, AOPA President and CEO Craig Fuller says the cuts are still a “moving target … we have yet to see a comprehensive sequestration plan and timetable.”

Fuller adds the association still has few details about precisely what that means for general aviation. “Unfortunately, even the people who make those decisions still aren’t entirely clear on what happens now,” he says.

AOPA, along with other general aviation groups, are watching closely because what has been clear is that general aviation likely will feel the brunt of those cuts. Most of the affected towers have fewer than 150,000 annual operations. FAA is also looking at scaling back maintenance of navigational aids at numerous airports, including those scheduled to lose airport towers.