ATLANTA — The deep pay cuts pilots at bankrupt Delta Air Lines have accepted may be the least of their worries: Their retirement benefits are in jeopardy as well.

Union leaders said yesterday Delta's 6,000 pilots are concerned that the nation's third-largest carrier would next seek to terminate their pension plan.

The latest pay cut agreement reached Wednesday, while painful, will at least buy its leaders some time to negotiate conditions that would be implemented if the pension plan is nixed, the Air Line Pilots Association said.

The union wants Delta to take the amount the airline has not paid to the pilots' pension plan since filing for bankruptcy on Sept. 14, and credit it toward a comprehensive concessions package the sides work out.

Pilots also are hoping to share in Delta's future profits and new equity that will be issued when it emerges from bankruptcy.

"They were trying to pocket the money they weren't contributing to the defined benefit pension plan, and we called their bluff on it," union spokesman John Culp said yesterday.

Culp said Delta missed $145 million in qualified pension contributions on Oct. 15 and has been refusing to pay roughly $7 million a month in nonqualified pension contributions.

"If they're going to stop supporting the plan, then contractually they have to deal with us," Culp said.

Delta spokeswoman Chris Kelly said the airline is unsure what will happen to the pension plan.

"We'll continue to work together with ALPA and Delta active and retired employees to try to save Delta's pension plan," Kelly said.

But, she added, "There are simply too many factors, some of which are beyond the company's control, to be able to make guarantees at this time."

Asked about the union's contention that it should be given credit for the money the airline has saved so far in missed pension contributions, Kelly would not comment.

Congress is debating pension reform legislation that could help Delta spread out the payments of future obligations to its pension plan. But even if that reform comes, it may not be enough.

The 14 percent cut in wages and other cuts equal to an additional 1 percent wage reduction that pilots agreed to Wednesday are on top of a 32.5 percent pay cut the pilots agreed to last year as part of a $1 billion annual concessions package.

Delta had been seeking to void the pilot contract so it could impose $325 million in new concessions on its pilots, but agreed to an interim deal worth less than half that. The two sides will now try to work out a comprehensive deal by March. If they can't, a three-person arbitration panel will decide the fate of the pilot contract.