WASHINGTON >> Flight attendants at American Airlines rejected a five-year contract Sunday, forcing the world’s largest carrier and its union for cabin-crew workers into binding arbitration.

Just 16 votes blocked the contract — with 8,180 voting for and 8,196 voting against, the Association of Professional Flight Attendants said in a statement.

The rejection of the contract affects roughly 24,000 workers and complicates the integration of American Airlines and US Airways. The two merged last year to form the world’s biggest airline operator. The proposed contract included guaranteed raises but ended a profit-sharing plan.

American Airlines said in a statement that it was "disappointed" by the vote.

"This tentative agreement included industry-leading pay and benefits, and would have provided considerably more economic value and much better work rules than the contract that will be determined by arbitration," it said in a statement.

Last month, American Airlines Group Inc., based in Fort Worth, Texas, reported an all-time best $942 million profit in the June-through-September quarter, nearly double the amount that American and US Airways earned separately last year. CEO Doug Parker predicted more records for the fourth-quarter.

The first arbitration meeting is scheduled for Dec. 3, the union said.