On February 24, 2014, at 1330 central standard time, a Robinson R44II helicopter, N360AH, rolled over while hovering in Presidio, Texas. The pilot and one passenger were not injured. A second passenger was seriously injured. The helicopter as substantially damaged. The helicopter was registered to Nopal Services LLC, and was operated by the private pilot as a 14 Code of Federal Regulations 91 personal flight. Visual meteorological conditions prevailed and no flight plan was filed. The local flight originated from Presidio, Texas. The pilot reported he was surveying ranch land and was hovering at an altitude of 12 to 15 feet above the ground just prior to the accident. He reported he was transitioning to forward flight and was not able to maintain sufficient power and altitude. The low rotor rpm horn sounded and the pilot decreased the collective to try and "fly out of it", but the helicopter was too close to the ground. The helicopter lost tail rotor effectiveness and spun around one revolution prior to contacting the ground and rolling over. The pilot reported that there were no mechanical failures/malfunctions of the helicopter that would have prevented the normal operation of the helicopter.