Investigators analyze flight data to understand the crash between an American Airlines jet and a military helicopter and exactly what was going on before disaster struck.

A preliminary safety report from the Federal Aviation Administration reportedly found that air traffic control staffing was abnormally low at Ronald Reagan Washington National Airport on the evening of Wednesday, Jan. 29, according to The New York Times, which obtained a copy of the report.

There was no immediate word on casualties, but all takeoffs and landings from the airport near Washington have been halted.

The report, reviewed by The New York Times, said that one controller was communicating with both helicopters and planes. Those jobs are typically assigned to two people, not one.

The airspace around Ronald Reagan Washington National Airport has long been problematic due to heavy military and commercial flight activity in the nation’s capital, according to industry insiders.

According to the Patrick Leahy Burlington International Airport website, three American Airlines flights between DCA and BTV were canceled for Wednesday night and Thursday morning.

Ronald Reagan Washington National Airport is closed, according to an FAA alert posted Wednesday night. A ground stop will prevent planes from landing at the airport through at least 5 a.m. Thursday morning,

Political leaders had warned about the dangers of Ronald Reagan Washington National Airport in Washington, D.C. months before an American Airlines flight collided with a U.S. Army Black Hawk helicopter on its approach to the airport.

Ronald Reagan Washington National Airport (DCA) services both military helicopters and passenger planes every day.

Airport preferred by Washington lawmakers and lobbyists lies in some of the most congested airspace in the country.

Deadly mid-air collision over Washington, D.C., reignites concerns over air traffic congestion and safety risks at Ronald Reagan Washington National Airport