The U.S. Army confirmed that one of its helicopters collided with a small drone in domestic airspace on September 21 in what the service described as the first such incident. The Army is now reviewing its procedures for missions like the security flight it provided for the United Nations General Assembly meeting in New York City, where the collision happened.

While flying over Staten Island at 500 feet at 7:30 p.m., an Army UH-60M Black Hawk assigned to the 82nd Airborne Division collided with what appeared to be a “civilian quadcopter,” said Lt. Col. Joe Buccino, public affairs officer for the division, based at Fort Bragg, North Carolina. The collision caused “minor” visible damage to a main rotor blade and a window on the upper left-hand side of the helicopter, which landed safely at Linden Airport in New Jersey.

Four crew were flying in the helicopter, one of two Army Black Hawks providing security for the annual General Assembly session, which drew world leaders including President Donald Trump to New York City. As a precautionary measure, the Army replaced the affected rotor blade and returned the helicopter to service within 24 hours, Buccino said.

The FAA confirmed that it was assisting with the investigation of the incident, but said the U.S. Secret Service was the lead agency for media inquiries. The latter agency referred questions to the New York field office of the FBI, which said it was assisting the Army's investigation. The New York Police Department said it was also cooperating with the investigation, but it referred questions to the FAA and the military.

Buccino said the Army is rethinking its procedures for domestic missions over populated areas. “We traditionally fly [in] restricted airspace or in combat, so this is a new experience,” he said. “We were obviously flying over a residential area—a municipal area—supporting this mission. We are reviewing the process now should we receive another mission like this.”

Staten Island was in fact covered by a Temporary Flight Restriction at the time of the collision on September 21, which disallows civil drone-flying activity. FAA safety guidelines also call for keeping recreational drones below 400 feet and beyond five miles of an airport or heliport. Although the Army reported the drone was flying above 400 feet, the location of the collision over the eastern shore of Staten Island is not within five miles of either Newark Liberty International or Linden airports.