On August 2, 2016, about 1027 mountain standard time (MST), a Robinson R22 helicopter, N22UH, landed hard at Ernest A Love Field Airport, Prescott, Arizona. The certificated flight instructor and student pilot received minor injuries. The helicopter sustained substantial damage to the fuselage and the tail boom. The helicopter was registered to Alba Leasing Services and operated by Universal Helicopters under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 as an instructional flight. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight departed Prescott, Arizona, about 0950. The student pilot and the flight instructor were practicing straight in autorotations. During the glide, with the student pilot at the controls, about 400 feet above ground level, the flight instructor noticed a fast rate of decent and a decay in rotor RPM. The flight instructor stated to the student that he had the controls and started applying collective and throttle control to recover RPM. The instructor felt the collective go up and stated again to the student that he had the controls. The flight instructor was unable to arrest the decent or recover RPM prior to the hard landing. During touchdown, the landing skids collapsed, the main rotor blades connected with and severed the tail boom. The helicopter came to rest on its left side. The flight instructor reported no pre-impact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation.