Last month, an American Airlines passenger jet and an Army helicopter collided as the plane prepared to land at Washington D.C.’s Ronald Reagan National Airport.

The Federal Aviation Administration said the Learjet 35A veered off the runway as it arrived at Scottsdale Municipal Airport around 2:45 p.m. It hit a Gulfstream 200 business jet that was parked on private property, officials said at a news conference.

The National Transportation Safety Board provided an update on Friday into the investigation of the deadly Army Black Hawk helicopter and American Airlines flight collision.

LIVE: Watch the NTSB press conference in the video player above. The collision was the deadliest plane crash in the U.S. since 2001, when a jet slammed into a New York City neighborhood just after takeoff,