American Airlines Inc. and its Transport Workers Union kick off 12 days of intense talks on Tuesday in hopes of getting a quick contract deal.

It'll mark the third time in 15 months that the airline and union have stepped up their negotiations with a goal of coming out with a new contract quickly.

But the two previous efforts foundered when union members objected to American's proposals on pay, benefits and concessions, and the outlook for a deal on this round remains about as uncertain as the U.S. economy.

The union, which asked for the latest round of accelerated discussions, and American have agreed to ask the National Mediation Board to step in and mediate the negotiations if the two sides don't work out an agreement by midnight Dec. 13.

"American's objective remains to reach an agreement that will address the key areas of interest as identified by the TWU," American spokeswoman Tami McLallen said Monday, "while recognizing the economic and competitive realities currently facing the industry and company."

"I think that both the company and our members want to get an agreement. In the next few days, we will either have a contract or we will be jointly filing for federal mediation," said John Conley, director of the TWU's Air Transport Division.

"TWU members have waited for a long time to come to terms with American," he said.

"According to the airline analysts, next year could be a very good year for AA, and the time to sign on the dotted line is now."

These talks involve TWU members who work as fleet service clerks, stores employees, ground school instructors and simulator technicians.

TWU-represented mechanics and related employees are not involved in this round of discussions, although anything negotiated would affect the talks for the other TWU members, as well as negotiations with the Allied Pilots Association and the Association of Professional Flight Attendants.

American began formal contract talks with the pilots in September 2006, the TWU in November 2007 and the flight attendants in June.

All contracts became amendable May 1; under federal law, airline labor contracts do not expire.

All three unions are trying to win back concessions on pay, benefits and work rules negotiated in 2003 as the airline was fighting successfully to stay out of bankruptcy court.