On July 20, 1993, about 0845 eastern daylight time, a Head AX8-105 balloon, N45124, registered to Charles M. Vaughn, dba Balloon Man, landed hard near Jacksonville, Florida, while on a 14 CFR Part 91 sightseeing flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The balloon was not damaged and the pilot and one passenger were not injured. One passenger sustained serious injuries. The flight originated about 0730 from Jacksonville, Florida. The pilot stated that he initiated a descent to land in a field but observed a fence in the middle of the field. He added burner heat and cleared the fence but according to the passenger, the pilot told him to pull the red lanyard when the balloon was 15-20 feet above ground level. The pilot never advised him of the effect of pulling the red lanyard which opens the deflation panel at the top of the envelope. The other passenger stated that the pilot told her it was going to be a rough landing and while she was sitting down, the balloon landed "like a rock."