We now know more about the deadly plane crash that killed a doctor and his teenage son in Jackson County earlier this month.

A preliminary report from the National Transportation Safety Board shows Dr. David Holtrop was not instrument rated to fly in bad weather. Holtrop's single engine plane crashed in a remote, wooded area southeast of Osseo. Witnesses told the NTSB it was rainy and foggy that night.

Holtrop and his 16-year-old son Max were flying from the Lake Elmo Airport near St. Paul. They were on their way home to Sheboygan.

Dr. Holtrop's colleagues say they were on their way home from a paintball convention to celebrate Max's birthday.

The doctor's biography shows he briefly worked in Chippewa Falls before he moved to Sheboygan in 1989.

It could be up to a year before the NTSB issues its final report.