American Airlines and the Allied Pilots Association have formally challenged a union representing pilots of the former US Airways, urging a federal court to deny that union’s request that federal arbitration be used to determine a seniority integration plan at the newly merged airline.

In a court filing made late Friday, Fort Worth-based American said a Memorandum of Understanding reached last year with the two pilots unions, the APA and the US Airline Pilots Association, lays out a specific process on how to determine an integrated seniority list.

“The Company seeks to put a stop, once and for all, to USAPA’s bad-faith behavior in trying to escape the provisions of the MOU regarding seniority integration for the pre-merger US Airways and pre-merger American pilot groups,” American said in its filing.

American asserted that the agreement specified that any arbitration needed to resolve a seniority integration dispute be held after American and its pilots have received a new contract.

USAPA filed its lawsuit in federal court in Washington, D.C., earlier this month, alleging that since the parties could not agree on a seniority integration process, it should be determined by a federal arbiter as prescribed under federal law.

The APA, which represents pilots at American, said it expects to be named the legal bargaining unit for all of the pilots at the merged airline and asked the court to rule that only APA can determine if any USAPA members can participate in the seniority integration process.

“APA seeks a further declaration that, following USAPA’s decertification as the collective bargaining representative for legacy US Airways pilots and its replacement by APA as the collective bargaining representative for all US Airways and American pilots, USAPA may only participate in the MOU seniority integration process if and to the extent deemed appropriate by APA,” the union said in a court filing.

This is not the first time that US Airways pilots have been involved in a legal battle over seniority integration. The pilot groups at US Airways and America West, which merged in 2005, never integrated as the “East” pilot group contested a seniority list and the “West” pilot group argued that the union did not represent it fairly.

If the American and US Airways pilot groups cannot sort out seniority integration in a timely fashion, the company could take legal action to enforce the timetable spelled out in the MOU. According to that document, the union needs to give American a final seniority list by Dec. 9, 2015.

Photo Credit: The American Air and US Airways leadership team in a sea of pilots after the merger was announced. Ron T. Ennis / Fort Worth Star-Telegram/MCT