U.S. Transportation Secretary Sean Duffy says it’s “unacceptable” that two commercial jetliners had to abort landings this week at Ronald Reagan Washington National Airport because of an Army Black Hawk helicopter.

The incident Thursday afternoon occurred three months after 67 people were killed in a mid-air collision near the airport between a Black Hawk and a passenger jet.

In an email reported by Politico, Chris Senn, Federal Aviation Administration assistant administrator for government and industry affairs, said the Army helicopter “took a scenic route around the Pentagon versus proceeding directly from the west to the heliport.”

Senn said the helicopter violated safety standards and required air traffic controllers to order two commercial jetliners to perform “go-around maneuvers,” aborting their landings and returning on another approach.