WASHINGTON (AP) — The head of the Senate Armed Services Committee says new U.S. Air Force leaders must fix the problems at the beleaguered service, which has been under fire for mishandling some of its nuclear responsibilities.

Sen. Carl Levin acknowledges it’s “a very very difficult time” for the service. He spoke at the opening of a confirmation hearing for two men nominated to take the place of Air Force leadership fired last month.

Michael Donley is nominated to be the new Air Force Secretary, and Gen. Norton Schwartz has been chosen to be its chief of staff.

The pair say they know one of their big challenges will be to restore confidence and trust in the Air Force.