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.

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.

A preliminary FAA report says that staffing at the D.C. airport’s air-traffic control tower was “not normal for the time of day.”