FORT WORTH, Texas – A federal judge has blocked a union-organizing election for nearly 10,000 employees at American Airlines.

Judge Terry R. Means ruled Friday that the Communications Workers of America needed signed cards showing that 50 percent of the eligible workers were interested in union representation to earn an election.

The union had argued that it needed 35 percent, the standard until Congress changed the rules in February. The union applied for an election before the change.

The union gave notice Friday that it intends to appeal the judge’s decision to the 5th U.S. Circuit Court of Appeals in New Orleans.

It also will appeal a ruling that barred it from joining the case.

American sued the National Mediation Board, a federal agency that oversees union elections, after the board scheduled voting among nonunion ticket counter and airport gate agents.

Means, who oversaw a brief trial in his Fort Worth courtroom this month, ruled that the 50-percent standard applied by the time the mediation board reviewed the union’s election request in April.

He issued an injunction barring the board from conducting any further election-related activities.

The dispute had gained attention outside the airline industry. Leading Democrats in Congress had asked American to allow the election to go forward.

The ruling comes as American, which filed for bankruptcy protection in November, separately seeks to break contracts it negotiated with other unions that represent pilots, flight attendants and mechanics.