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 not be allowed to travel over a four-mile stretch over the Potomac River following the deadly air collision near Washington in January, according to urgent safety

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 Federal Aviation Administration says helicopters will be permanently banned from flying near Washington, D.C.’s airport on the route where an airliner and an Army helicopter collided in midair.

The Federal Aviation Administration said on Friday it is imposing permanent restrictions on non-essential helicopter operations around Washington's Reagan National Airport and eliminating helicopter and passenger jet mixed traffic.