Pilots for Sun Country Airlines, who have been working under terms of an old contract for five years, have voted to authorize a strike if further federal mediation efforts toward a new deal are unsuccessful.

But no work action is imminent, leaders of the Air Line Pilots Association acknowledged Wednesday.

"We are not going on strike, but we are authorizing the leadership to set a date," ALPA spokesman Jake Yockers said. "If mediation is unsuccessful, we then go to arbitration and then there would be a 30-day cooling off period. No strike is planned."

Sun Country had no comment on the development.

Mendota Heights-based Sun Country has 246 pilots on its roster. Of those who were eligible to vote and did vote, 100 percent approved strike authorization, Yockers said.

"We hope this sends a message that we are serious about getting a new contract," Yockers said.

The next round of negotiations is set for March.

Under the federal Railway Labor Act, contracts for airline pilots don't expire, they become amendable. In the case of the Sun Country pilots, the contract became amendable in 2010.

Sun Country's fleet consists of about 20 Boeing 737s.

According to the ALPA, a 737 captain at Sun Country is paid at a rate that is 62 percent of the pay for a comparable pilot at Delta Air Lines and 69 percent of a contemporary at Spirit Airlines.

Privately held Sun Country does not release detailed financial statements, but reports filed with the U.S. Department of Transportation showed that the airline has been profitable in recent years. However, net income sagged in 2013 because of scheduled maintenance expenses and competition from low-cost competitor Spirit Airlines.