The flight instructor reported that he asked the pilot receiving instruction to demonstrate a run-on landing on the sod between the runway and taxiway. He reported that as the helicopter touched down at about 25 miles per hour (21.72 knots), the pilot lowered the collective to the full down position while the helicopter was still moving forward with considerable momentum. The helicopter began to "lurch forward" and the nose of the helicopter started to lower. The flight instructor then came on the flight controls, but the helicopter had progressed to an "extreme nose low attitude," and he applied aft cyclic to prevent the main rotor blades from impacting terrain. The main rotor blades instead impacted and separated the tailboom. The fuselage continued moving forward and the nose impacted terrain and then settled back on the skids. The helicopter sustained substantial damage to the fuselage, main rotor system, tailboom, and tail rotor system. The flight instructor verified that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. The flight instructor reported that he recommended landing on sod due to potential wear on the bottom of the skids from friction with the paved runway. He also reported that the pilot had successfully performed run-on landings in the past on the sod area. As a safety recommendation, the flight instructor reported that landing the helicopter on the runway instead of the sod may have lessened the effects of improper application of the collective at touchdown. He reported that he should have verbally reviewed the importance of using the collective to control the friction with the landing surface while in the traffic pattern to ensure the pilot's intentions were mutually understood. He further reported that he should have maintained a guarded position on the flight controls regardless of the pilot's abilities to decrease the flight instructor's reaction time for maneuver recovery. Enstrom Helicopter Corporation has published the Enstrom 280F Training Maneuvers Manual (2014). This manual discusses objectives and descriptions for a shallow approach and run-on landing, and states in part: Caution, Enstrom does not endorse practicing run-on landings. Run-on landings should only be accomplished on a smooth, hard surface; and should always be planned to the center of the runway to preclude sliding off the runway, and overturning. After ground contact, maintain heading with pedals and maintain collective position. Ensure that power is maintained until the helicopter comes to a complete stop to insure directional control. The Federal Aviation Administration has published the Helicopter Instructor's Handbook FAA-H-8083-4 (2012). This handbook provides instructional information for a shallow approach and run-on landing and states in part: In any case, do not rapidly lower the collective after touchdown. Smooth reduction of collective prevents a rapid stop that could result in damage to the aircraft or injury to the crew. For helicopters equipped with skids, it may be better to practice running landings on a hard surface runway instead of on a grassy field because there is less probability of catching a skid, which can lead to dynamic rollover. In addition, check the condition of the skid shoes before and after practicing running takeoffs and landings.