Air traffic controller furloughs scheduled to begin April 21 could cause an average flight delay of 50 min. at Chicago O’Hare International Airport and delays as long as 210 min. Hartsfield–Jackson Atlanta International, FAA and U.S. Transportation Department (DOT) officials say.

O’Hare and Hartsfield are just two of 13 airports that will see “heavy to moderate” flight delays because of the furloughs, which are necessitated by the sequester-driven cuts in the federal budget, FAA Administrator Michael Huerta said during an April 18 briefing at DOT headquarters.

Huerta and Transportation Secretary Ray LaHood at that briefing identified the airports and provided detailed delay predictions for six of them. Huerta noted that he expects the maximum delays to be “infrequent.”

Those predictions showed maximum and average delays of 51 min. and 20.5 min. for Newark Liberty International Airport, 50 min. and 12.4 min. for John F. Kennedy International Airport, 80 min. and 30.5 min. for LaGuardia Airport, 132 min. and 50.4 min. for O’Hare, 67 min. and 10.1 min. for Los Angeles International Airport and 210 min. and 11.3 min. for Hartsfield.

Huerta says those airports are illustrative of the range of impacts at all 13 airports. The other seven he identified, without accompanying delay predictions, were Charlotte Douglas International Airport, Chicago Midway International Airport, Fort Lauderdale-Hollywood International Airport, Miami International Airport, Philadelphia International Airport, San Diego International Airport and San Francisco International Airport.

LaHood and Huerta say they briefed airlines on April 16 on the FAA’s forecasted impact, but note that it is up to the airlines to decide how to respond.

“We’re telling them what we can handle,” Huerta said. “It’s really up to the airlines to reduce the schedules, if they choose to do so.”

The FAA says it will furlough 47,000 employees, including controllers, for as many as 11 days between Sunday and Sept. 30, the end of the fiscal year. That amounts to one day for every two-week pay period.

Several factors will contribute to the extent and duration of the delays at the 13 identified airports, including peaks and valleys in service that provide room for delay recovery and the effect a reduction in controller hours will have on runways usage.

Huerta reiterated that the reductions could compel O’Hare, at times, to close its North Tower and consolidate all controllers at the Central Tower, which would mean closing one runway. At Kennedy, staffing limitations could sometimes prevent simultaneous use of parallel runways, and at Hartsfield, situations could arise where the airport would not be able to make use of all five of its parallel runways.

Huerta and LaHood, however, concede that only experience will provide data on how each airport is affected, and how much that impact could ripple to other airports in the domestic system.

“This is going to be a very dynamic situation,” Huerta said.

The FAA arrived at its estimates by analyzing traffic levels in 15-min. increments on March 29—a busy travel day with clear weather—and plotting that against the expected reduction in its hourly acceptance rate for arrivals under visual flight rule conditions. That gave it the expected arrival rate if airlines do not change their flight schedules.