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

The NTSB is, however, making “urgent safety recommendations,” per Homendy, regarding helicopter routes near Ronald Reagan Washington National Airport. “Urgent recommendations require immediate action to prevent similar accidents or incidents when we issue them,” Homendy said. “We believe a critical safety issue must be addressed without delay.”

Investigators issued their preliminary report Tuesday in the probe into the devastating crash between an American Airlines plane and a U.S. Army Black Hawk helicopter.