FAIRBANKS, Alaska (AP) — Authorities say two U.S. Army helicopters that crashed last week in Alaska, killing three soldiers, collided over a rugged, mountainous area. A U.S. Army spokesperson said Sunday there were no weather issues or visibility problems at the time of the accident. The two AH-64 Apache helicopters were returning to Fort Wainwright from an aerial gunnery range southeast of Fairbanks when they collided Thursday. The Army grounded aviation units on Friday to conduct further training following recent deadly helicopter accidents in Alaska, Kentucky and Alabama. Investigators are planning to fly to the accident scene Monday morning.