On March 30, 2001, at approximately 0734 central standard time, a Piper PA-18A-150, N7471D, collided with trees 75 yards due east of Ruckel Airport in Niceville, Florida. The positioning flight was operated by Aerial Sign Company under the provisions of Title 14 CFR Part 91 with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane was destroyed. The commercial pilot received serious injuries. The positioning flight departed Ruckel Airport in Niceville, Florida, at 0730 central standard time. According to the pilot, the purpose of the departure was to take a quick flight around the traffic pattern to see what the weather looked like away from the airport. He stated that he flew to the departure end of the 3,000 foot grass strip and turned right for downwind to land back at the airfield. He further stated that as he entered a right 20 degree bank the aircraft lost power and departed controlled flight. According to an eyewitness, who lives approximately 250 yards west of the runway centerline, first sighted the airplane when it was already airborne in a shallow climb. He stated that the airplane began to enter the base of the clouds, but did not fully disappear into the clouds. He stated the airplane immediately leveled off and then began a shallow right turn. He further stated as the airplane's nose passed through approximately northeast, he lost sight as his view of the airplane became restricted by his house and trees. He then stated approximately 5-10 seconds later, he heard the sound of the airplane impacting trees. Examination of the accident site, showed the airplane struck pine trees in it's descent and flipped inverted at a 75 degree nose down angle. Examination of the engine revealed no evidence of internal failure, no loss of required electrical spark or any fuel system abnormalities.