U.S. Army grounds all non-critical aircraft after latest fatal mid-air collision

The U.S. Army on Friday grounded all aircraft — except those in "critical missions" — following a mid-air collision Thursday involving two helicopters in Alaska which left three soldiers dead and a fourth wounded. It marked the second such mid-air collision in the last month.

The Army said in a news release provided to CBS News that Chief of Staff James McConville ordered the "aviation stand down" after the two recent fatal accidents which claimed the lives of 12 soldiers, including a mid-air collision involving two Black Hawk helicopters near Fort Campbell, Kentucky, March 29 which left nine soldiers dead.

All aviators, except those in critical missions, are grounded until they "complete the training," the Army said.