Negotiations between Northwest Airlines ( NWACQ) and its pilots reached a critical point Thursday as a bankruptcy court deadline for a deal expired.

Meanwhile, talks between Delta Air Lines ( DALRQ) and its pilots are headed for arbitration.

In the Northwest case, it's unclear when U.S. Bankruptcy Court Judge Allan Gropper will issue a ruling on whether the airline can impose contract terms on its pilots, a move that would likely lead to a strike. Gropper didn't say when he would rule, according to a Wednesday night posting on the Web site for the Northwest chapter of the Air Line Pilots Association.

"Under the law, Northwest technically could implement its proposal pending decision by the judge, but ALPA does not expect the company to do so absent advance notice," the posting said.

Both sides have said that progress is being made in the talks, but crucial issues remain. Northwest did, however, reach a deal with its flight attendants union on Wednesday. That agreement involves wage concessions of $195 million annually, as the airline seeks to reduce annual labor costs by $1.4 billion.

The International Association of Machinists is presenting a contract settlement proposal to Northwest ground workers.

At Delta, the airline and its pilots are going to arbitration after failing to reach a deal by the deadline for a negotiated settled. Arbitration is slated to begin March 13. Delta has indicated it wants to impose $325 million worth of cuts in bankruptcy court, after pilots agreed in 2004 to accept about $1 billion worth of concessions.

Both Delta and Northwest filed for bankruptcy court protection last September.

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