An Army helicopter flying in the D.C. airspace Thursday forced two commercial passenger jets inbound to Ronald Reagan Washington National Airport to perform go-around maneuvers — roughly three months after the airport was the site of the nation’s worst aviation fatality in more than two decades.

The National Transportation Safety Board is now investigating the aborted landings of two commercial flights approaching Reagan National Airport on Thursday as a U.S. Army Black Hawk helicopter was approaching the Pentagon nearby.

The Black Hawk was trying to land at the Pentagon’s heliport, bringing it close to a pair of airliners, according to the Federal Aviation Administration.