On October 16, 2004, about 1250 central daylight time, a Schweizer 269C, N119DM, registered to and operated by a private individual, as a Title 14 CFR Part 91 personal flight, caught fire during shutdown near Diamondhead Airport, Diamondhead, Mississippi. Visual meteorological conditions prevailed and no flight plan was filed. The private-rated pilot and one passenger received no injuries, and the helicopter was destroyed. The flight had originated 15 minutes earlier from the Diamondhead Airport. The pilot stated that a few minutes after departure, he performed a precautionary off airport landing in cleared area in marsh section next to the bay, to correct a sticking floor push-to-talk microphone switch. The helicopter was shut down and pilot corrected the sticking microphone switch. The helicopter was started and as it took off to a hover it spun to the right. The pilot managed to land the helicopter in the marsh area. He shut down the helicopter; however, the grass caught fire from the heat of the engine exhaust system. The fire quickly spread, consuming the helicopter and a section of the marsh area before the fire department arrived to extinguish the fire.