Federal investigators say the teenage pilot of a small airplane didn't have any radio contact before the aircraft crashed in Alabama on New Year's Day, killing the 17-year-old and two friends who were on board.

The National Transportation Safety Board released its preliminary report Thursday. It says authorities learned of the crash in Walker County after witnesses called 911.

The report doesn't say what caused the crash.

The report backs up authorities who say the pilot took the twin-engine Piper airplane on a joyride and crashed.

While the pilot's mother denies he stole the plane, the NTSB report says the airplane's owner didn't give the youth keys to the plane and didn't let him fly it.

The teen pilot, Jordan Ryan Smith, had worked at the Jasper airport, cleaning the facility.