The final report on a fatal plane crash says the pilot was to blame.

The crash happened on September 5, 2009 in Chandler Park. 

The crash killed the pilot, Dr. Stephen Lester, his family and a family friend.

On board the plane was Lester’s wife Dana, daughters Laura and Christina, and Dr. Ken Veteto.

Authorities with the National Transportation Safety Board say the pilot was advised not to fly that day because of the heavy mist.

NTSB investigators say, "The non-instrument-rated pilot's decision to attempt flight in instrument meteorological conditions, which resulted in spatial disorientation and an in-flight collision with a radio tower guy wire."

Investigators believe Dr. Lester was disoriented because of the low visibility.

The group took off from Jones Riverside Airport in a single-engine Piper Cherokee to fly to Dallas for an OU football game.