On April 24, 2004, approximately 1050 central daylight time, a Robinson R22 Beta helicopter, N819TT, piloted by a certified flight instructor (CFI) and a dual student, was substantially damaged during an in-flight collision with terrain near Shakopee, Minnesota. The instructional flight was being conducted under 14 CFR Part 91 and was not on a flight plan. Visual meteorological conditions prevailed. The CFI and dual student reported no injuries. The local flight departed the Flying Cloud Airport (FCM), Minneapolis, Minnesota, about 1015. The CFI reported that they were approximately seven miles southwest of FCM practicing normal approaches when the accident occurred. He stated that the third approach was made to an open field and was terminated in a hover about five feet above ground level. The helicopter began yawing to the right and when the dual student did not correct for the rotation, the CFI applied left pedal to stop the yaw. The CFI reported that as he applied the left pedal control input, the dual student stated "You have it" and simultaneously made a "strong" right cyclic input. As he attempted to recover, the dual student "abruptly" raised the collective without increasing the throttle causing the rotor speed to decay. The CFI reported that the helicopter climbed and then began to settle toward the ground in a "right drift." He stated: "I was unable to recover the [rotor speed] or align the skids with the ground track before the right skid hit the ground. The skid dug in causing the helicopter to roll over on its right side." The dual student, who held a private pilot certificate with single and multi-engine airplane ratings, stated: "I brought the helicopter to within about 5 to 10 feet of the ground and attempted to hover. The helicopter turned a bit to the right and tilted to the left." He reported that he immediately attempted to transfer control to the CFI, saying "It is yours." The dual student reported that the CFI acknowledged. The dual student noted that the helicopter's movement seemed to become "more severe." He stated: "I sat with my hands and feet off the controls as the gyrations became progressively worse. Then it felt as though the body of the helicopter began to rapidly spin to the right. . . . My impression was that the right skid hit the ground and the helicopter slammed onto its right side." The CFI and dual student both reported that there were no failures or malfunctions associated with the helicopter. A Federal Aviation Administration inspector verified control continuity during the post-accident examination. No anomalies consistent with a pre-impact failure were observed. The CFI reported a total flight time of 247 hours, with 63 hours in the Robinson R22 Beta. He reported instructor flight time as 5.6 hours total and 0.4 hours in the R22.