At 1606 Eastern time, the airplane was substantially damaged while landing at the Warren Airpark in Warren, Penn. The Private pilot received serious injuries and the passenger was fatally injured. Visual conditions prevailed for the personal flight that departed Butler, Penn., about 45 minutes earlier. According to a witness, the airplane touched down on Runway 6, then departed it to the right. The airplane then disappeared from his view, but he heard its engine RPM increase prior to the airplane impacting trees. A weather observation taken about 13 minutes prior to the accident 26 miles to the southeast included wind from 040 degrees at 11 knots with gusts to 18 knots.