National Transportation Safety Board investigators issued a pair of “urgent” safety recommendations for helicopter paths on Tuesday as part of their preliminary report into the deadly midair collision over the Potomac River in January.

Helicopters should be barred from a four-mile stretch over the Potomac River when flights are landing on Reagan National Airport’s Runway 33, National Transportation Safety Board Chair Jennifer Homendy said as the NTSB unveiled “urgent safety recommendations” after the deadly mid-air collision in January.

The National Transportation Safety Board on Tuesday released two reports — one on preliminary findings and another on safety recommendations — related to the deadly collision of an Army Black Hawk helicopter and an American Airlines regional jet in January. The crash killed 67 people.