WASHINGTON —  The two men nominated to replace the ousted U.S. Air Force leadership said Tuesday they will work to restore trust and confidence in the beleaguered service, under fire for poor handling of its nuclear duties and other missteps.

Michael Donley, the nominee for secretary of the Air Force, told a Senate confirmation hearing that service's senior leaders "are ready to put the difficulties of the past few months behind them ... to learn the appropriate lessons from these experiences and to move forward.

He appeared beside Gen. Norton A. Schwartz, who has been nominated for Air Force chief of staff.

Senators want to hear what Donley and Schwartz will do to take the Air Force in a new direction. But some are skeptical about whether the leadership change can solve systemic problems at the service, especially with only six months left in the Bush administration.

Opening the hearing before the Senate Armed Services Committee, its chairman, Sen. Carl Levin, noted this is a "very very difficult time" for the Air Force. The Democrat told the nominees that their jobs "will be to fix the underlying problems and not just the symptoms."