On July 16, 2005, about 1019 central daylight time, a Robinson R-22B, N2614D, registered to and operated by Vortex Helicopters Incorporated, as a Title 14 CFR Part 91 instructional flight, crashed in Gulfport, Mississippi. Visual meteorological conditions prevailed, and no flight plan was filed. The commercial-rated instructor and private-rated student were not injured, and the helicopter incurred substantial damage. The flight originated the same day, about 1000. The instructor said that he and the student had been operating the helicopter in the traffic pattern at Gulfport-Biloxi International Airport when the accident occurred. According to the instructor, the student was flying the helicopter, and they were in a left-handed traffic pattern, on the downwind leg at an altitude of about 550 feet, with the intent to practice maximum performance takeoffs and straight-in autorotative landings. The instructor stated that he reminded the student to activate the carburetor heat, as the student reached forward he heard the engine quit running, the instructor never "observed" the student pull the carburetor heat. The engine rpm immediately "dropped all the way down" and he heard the engine correspondingly cease to operate. The instructor said he immediately took control of the helicopter from the student, entered the autorotation, and affected a landing to a golf course. During the landing, the helicopter incurred damage, which included damage to the main rotor, tailboom, skids and skid supports. The student pilot stated that he was practicing maximum performance take-off and autorotative landings with his flight instructor. When they were on the downwind leg, the instructor reminded him to make sure the carburetor heat was on, as he reached down to pull the carburetor heat, the engine stalled. The student didn't recall pulling the carburetor heat control or if his hand was on the carburetor heat knob. He said the instructor took control of the helicopter and preformed an autorotation, flared "hard" to avoid trees on the golf course. Upon impact with the ground, the student observed pieces of the tail rotor fly by as they spun sideways. The instructor pulled the rotor break to stop the rotor blades from turning. They excited the helicopter and waited for the police to arrive. An onscene examination was conducted under the supervision of an FAA inspector, and the examination revealed that the fuel shut off lever was in the on position, the carburetor heat control was set to "Off", the mixture control was set to "Full Rich" and the guard was in place, the main and auxiliary fuel tank positions displayed the presence of fuel, and the engine Hobbs meter displayed 6019.0 hours. In addition, a follow-on examination, as well as a test-run was performed on the engine, and it operated normally with no anomalies being noted.