Primary finding
Probable cause
The pilot’s failure to maintain sufficient rotor rpm when transitioning the helicopter from a hover to forward flight, which resulted in a loss of helicopter control.
Investigator assessment
Analysis narrative
The pilot reported that he was surveying ranch land and that the helicopter was hovering about 12 to 15 feet above the ground just before the accident. While transitioning to forward flight, the helicopter was unable to maintain sufficient power and altitude. The low rotor rpm horn sounded, and the pilot decreased the collective to try to "fly out of it," but the helicopter was too close to the ground. The helicopter subsequently lost tail rotor effectiveness and spun around once before impacting the ground and rolling over. The pilot reported no mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
Source record
Factual narrative
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.