HELENA, Mont. -

A federal judge has approved the use of a helicopter to fly in equipment to repair a failing dam in the Selway-Bitterroot Wilderness.

Two environmental groups sued to block the repairs to the Fred Burr High Lake Dam, saying the use of a helicopter violates the federal Wilderness Act.

The wilderness act requires no motorized or mechanized uses in designated wilderness areas, with some exceptions.

U.S. District Judge Donald Molloy ruled Tuesday that the U.S. Forest Service's approval of the helicopter in this case qualified as an exception.

The helicopter would not land in the wilderness area and its flight would last less than an hour.

Molloy says that would be less disruptive than the trail improvements that would be required to pack in more than 1,100 pounds of equipment.