On July 15, 2012, at 0900 eastern daylight time, a Piper PA-18-150, N8048D, registered to Barnstormers Flite Signs Inc., operating as Title 14 Code of Federal Regulations Part 91 banner tow flight experienced a partial loss of engine power while attempting to pick up a banner. The airplane collided with an airport perimeter fence and sustained substantial damage. The commercial pilot reported no injuries. Visual meteorological conditions prevailed and no flight plan was filed. The flight originated from Grand Strand Airport (CRE), North Myrtle Beach, South Carolina at 0845. The pilot stated he turned on final approach at 300 feet above ground level (agl) and reduced the power to the idle position. His airspeed was between 60 to 70 mph. The carburetor heat was not activated, which is company policy. When the airplane reached about 10 feet (agl) and 50 feet from the banner pick up poles, he added full power and noticed the rpm was at 2,500 which was 100 rpm less than full power. The pilot pitched the nose up and climbed to 200 feet and the rpm continued to decrease to 1500 rpm. He lowered the nose and checked the throttle and it was full forward. He increased the mixture and there was no change. The airplane would not maintain altitude and he informed the tower that he was going down. He reduced the throttle to the idle position and lowered the flaps to the full down position. He made a forced landing beyond the banner tow grass area, clearing a berm and colliding with the airport perimeter fence. The airplane nosed over and came to a complete stop and the engine stopped running. The pilot turned the fuel off at the fuel selector. The pilot stated he did not experience any mechanical problems with the airframe or flight controls before the accident. The registered owner stated "It has never been the company policy of Barnstormers Flite Signs to advise a pilot "NOT" use the carb heat in the event of any emergency situation for obvious reasons." The temperature at the time of the accident was 73 degrees Fahrenheit and the dew point temperature was 72 degrees Fahrenheit. According the carburetor icing chart the airplane would encounter serious icing at glide power. Review of Advisory Circular 91-51A EFFECT OF ICING ON AIRCRAFT CONTROL AND AIRPLANE DEICE AND ANTI-ICE SYSTEMS states in paragraph 5 DISCUSSION b. " There are two kinds of icing that are significant to aviation: structural icing and induction icing....c. Small aircraft engines commonly employ a carburetor fuel system or a pressure fuel injection system to supply fuel for combustion. Both types of induction systems hold the potential for icing which can cause engine failure. (1) The pilot should be aware that carburetor icing can occur at temperature between 13 degrees Celsius (C) (20 degrees Fahrenheit (F) and +21C (70F) when there is visible moisture or high humidity. This can occur in the carburetor because vaporization of fuel, combined with the expansion of air as it flows through the carburetor, causes sudden cooling, sometimes by a significant amount within a fraction of a second. Carburetor ice can be detected by a drop in rpm in fixed pitch propeller airplanes and a drop in manifold pressure in constant speed propeller airplanes. In both types, usually there will be a roughness in engine operation. Some engines are equipped with carburetor heat for use in both prevention and removal of ice."