Three people were killed when two small airplanes, neither of which were in contact with air-traffic control, collided in the air over Boulder County on Saturday morning and crashed.

The Federal Aviation Administration says a single-engine Cessna 172, carrying a student pilot and a flight instructor, collided with a Sonex Xenos, a motorized glider carrying one person, according to the National Transportation Safety Board.

The collision happened at about 9 a.m. southeast of Vance Brand Airport in Longmont. The aircraft were flying at an altitude of about 7,000 feet when the crash happened.

A Boulder County first responder at one of two plane crash sites on Saturday, Sept. 17, 2022. (Handout)

The Boulder County Sheriff’s Office initially told The Colorado Sun that four people were killed in the collision, but the NTSB said the total number of fatalities was three.

Neither plane had a mid-air-collision warning system, according to the NTSB, and neither was required to have one. The pilots, who were flying under visual flight conditions rules, were also not required to be in contact with air-traffic control.

The Cessna had departed from Rocky Mountain Metropolitan Airport in Broomfield. The Sonex had taken off from Platte Valley Airpark in Hudson.

Mountain View Fire Rescue said the planes crashed between North 95th Street and U.S. 287 off of Niwot Road.

“The FAA and the National Transportation Safety Board will investigate,” the Federal Aviation Administration said in a news release. “The NTSB will be in charge of the investigation and will provide additional updates.”

It can take more than a year for the NTSB to release a final report on the cause of the crash.

The sheriff’s office said its detectives were also at the scene of the crash.

Authorities did not immediately release the identities of the people killed in the collision.

Mid-air collisions between aircraft are rare. The last one in Colorado happened in May 2021, when a Fairchild Swearingen Metroliner operated by Key Lime air collided with a Cirrus SR-22 while both aircraft were preparing to land at Centennial Airport.

The Cirrus, which was equipped with a parachute that deployed after the collision, crashed, but the two people aboard the plane were uninjured. The Metroliner landed safely but was heavily damaged.

UPDATE: This story was updated at 9:41 p.m. on Saturday, Sept. 17, 2022, with details throughout after the National Transportation Safety Board held a news conference on the crash.

Jesse Paul is a Denver-based political reporter and editor at The Colorado Sun, covering the state legislature, Congress and local politics. He is the author of The Unaffiliated newsletter and also occasionally fills in on breaking news coverage. A...