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

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 episode followed a fatal collision between a military helicopter and a commercial jet in January, and prompted concern and outrage among officials.