Rob Sherman's plane crashed after a "loss of control," authorities said Thursday in a report that also indicated the well-known activist was flying after dark contrary to restrictions on the type of pilot's license he had.
Sherman's single-engine plane went down about 6:19 p.m. Dec. 9 shortly after takeoff, National Transportation Safety Board officials said in a preliminary finding.
The wreck was discovered Saturday in a field near Marengo. The NTSB said Sherman, 63, had left in his Zenair CH601 at 6:12 p.m. from the Poplar Grove Airport headed to the Schaumburg Regional Airport to attend a holiday party for the Experimental Aircraft Association, of which he was a board member.
Sherman, who died of multiple injuries, was certified as a sport pilot. Sport pilots may operate light, single-engine aircraft with seating for just two people. In general, sport pilots have certain restrictions that include not flying after dark, according to the Federal Aviation Administration.
There were no communications between any air traffic controllers and Sherman, the NTSB said, adding the weather was clear during the flight.
The plane came down about 12.6 miles east of the Poplar Grove Airport. Investigators based the time of the crash on radar data.
The longtime Buffalo Grove resident and aviation enthusiast moved to Poplar Grove this summer to a home with a hangar. Sherman had a wife and two grown children.
The atheist activist gained fame challenging towns for displaying crosses on water towers in the 1980s. He ran for public office unsuccessfully, took on numerous causes of separation of church and state, and recently spoke out against a proposed extension of Route 53.
The impact of the crash sent the aircraft's left, main landing gear 190 feet southeast of the main wreckage, part of the right wing 100 feet southeast, and a small satchel bag 500 feet south.
In general, individuals seeking a sport pilot license need a valid driver's license or a third-class medical certificate. A third-class medical certificate requires an applicant be in good health but has less stringent standards than those for a commercial pilot. Sherman had a third-class medical certificate, FAA records show.