What happened
During an instructional flight, the pilot receiving instruction was performing a steep approach at an altitude of approximately 300 feet with an airspeed of about 35 knots. During this maneuver, the Certified Flight Instructor (CFI) asked the rated pilot if the throttle could be rolled off. The rated pilot responded affirmatively and immediately reduced the throttle.
Following this action, the CFI observed an immediate drop in rotor RPM. The CFI took control of the aircraft while it was in a vertical rate of descent. In an effort to recover the rotor RPM, the instructor lowered the collective pitch; however, due to the low altitude, forward cyclic was not applied to increase airspeed. The helicopter subsequently struck a sod area with significant force and rolled onto its left side. There were no injuries reported in the accident.