US Airways has asked a federal judge to resolve a seniority dispute involving its pilots.

Executives with the Tempe, Ariz.-based carrier said Monday's legal action in U.S. District Court in Phoenix is called a complaint for declaratory relief. They say the dispute has significantly stalled efforts to negotiate a joint contract covering the 4,000 pilots joined together by the merger of America West and US Airways five years ago.

The airline's pilots union says it will vigorously oppose the company's move. The US Airline Pilots Association says the court has no jurisdiction in labor contract negotiations.

Seniority is important to pilots and flight attendants because it dictates their schedules, pay, vacations and promotions.