The U.S. Court of Appeals has set a timetable for the Experimental Aircraft Association’s petition seeking reimbursement from FAA for air traffic services, giving the association until Oct. 23 to file a brief on its case and providing the agency until Nov. 22 to respond.

EAA filed the petition July 3 asking the U.S. Court of Appeals for the Seventh Circuit in Chicago to require FAA to refund more than $450,000 in payments that the agency charged for air traffic control services it provided during EAA AirVenture in Oshkosh, Wis., from July 29-Aug. 4.

FAA in May informed EAA that it was charging for travel costs, per diem expenses and overtime pay for the federal controllers brought in during AirVenture. The Oshkosh tower is usually run under the contract tower program, but FAA brings in nearly 80 controllers and supervisors to handle the 8,000-10,000 aircraft that fly into AirVenture.

FAA similarly had charged for services at Sun ’n Fun in Lakeland, Fla. when the tower there was under threat of closure. EAA signed a contract and agreed to pay the charges, but also included a letter noting that it was being done so under protest.

EAA calls the charges improper and unlawful since FAA “unilaterally” imposed fees without standard notice and comment period, and did not seek congressional authorization. Other associations, including the Aircraft Owners and Pilots Association, similarly have protested the charges, and lawmakers in both the House and Senate have called on FAA to reverse course on its plans to charge for these events.

But FAA justified the move to lawmakers, saying it has entered into reimbursable agreements for special events since 2010. “We have been reimbursed for providing services for NASCAR events, the Super Bowl, the PGA tour and other sports events,” FAA Administrator Michael Huerta had told lawmakers. “The services we provide for these events result in additional overtime costs, extended hours of operation at FAA facilities and, in some cases, the use of a temporary tower.”

FAA in August furnished its background of the charges to the court docket, including a record of charges incurred and its presence at the 2012 AirVenture. It also included an April memo when the contract towers – including the Oshkosh tower – were at risk of closure. That memo discussed beginning a dialogue over the charges at AirVenture.

FAA acknowledged that EAA would not “like that answer” regarding the potential of charges and that funding is tight for the association as well. But the agency also points out that EAA promotes the event as bringing in $100 million to the state of Wisconsin.

During AirVenture, EAA Chairman Jack Pelton reiterated his dismay over the charges and questioned the need. “FAA has no basis to say this costs them a nickel,” he said, noting the event had been fully budgeted. He also pointed to legislation passed in late April to cover controller salaries and contract tower operations, saying the event should not have been vulnerable to sequestration.

Pelton is also concerned that the costs could increase if sequestration continues. He has warned that the charges from the FAA could triple, at which point the viability of the event could be thrown into question.