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 Safety Transportation Board has found that helicopter traffic out of Ronald Reagan International Airport posed an “intolerable risk to aviation safety by increasing the chances of a mid-air collision” ahead of a crash last month that resulted in the deaths of 67 people.