The National Transportation Safety Board (NTSB) is launching a three-day hearing on the deadly plane crash that took place in Washington, D.C., in January. The crash, which involved an Army helicopter and an American Airlines passenger jet, claimed the lives of 67 people.

Wreckage is seen in the Potomac River near Ronald Reagan Washington National Airport, on Thursday, Jan. 30.  (Petty Officer 1st Class Brandon Giles, U.S. Coast Guard via AP)

The outlet, citing a source who was not authorized to speak publicly, noted that there is usually only one air traffic controller after 9:30 PM, but a supervisor let one leave early. The midair collision that left 67 dead occurred just before 9:00 PM local time.

A crane is seen on Monday, Feb. 3, near the site of the plane crash near Reagan National Airport. (Fox News)

However, a person familiar with the matter explained to Fox News Digital that the positions get combined regularly if air controllers have to step away from the console for breaks, or if they are involved in a shift change. Controllers may also have to step away when air traffic is light, the person explained, speaking on condition of anonymity to discuss internal procedures.