ERIE, Colo. -- A single-engine plane crashed Saturday afternoon just after takeoff from the Erie Airpark, killing both men on board.

The men have been identified as a flight instructor, Matthew Crine, 41, of Wheat Ridge; and a student pilot, Emmet Murphy, 58, of Riverton, Wyo.

The crash, reported at about 2:48 p.m., closed Colorado Highway 7 between County Line Road and Lowell Boulevard for a time.

Witness Karilyn Clark told 7NEWS she saw a single-engine plane taking off from the Erie Airpark when it appeared to have difficulty turning back toward the airport and spiraled into the ground.

The plane was registered to Skyraider Aviation, a company that trains pilots on light aircraft.

The plane crashed in a field near the 300 block of Airport Drive.

Investigators with the National Transportation Safety Board say it appears the plane was trying to turn around, possibly to go back to the airport. They say it is too soon to know what caused the accident. The investigation will take six to eight months.