Incident Overview
A helicopter was engaged in a mission to harvest Nilgai antelope. After a passenger shot a second antelope, the pilot maneuvered the helicopter downwind at 50 knots and 70 feet above ground level to guide the animal recovery vehicle to the location of the first antelope. The pilot then executed a right turn to bring the helicopter into a hover over the fallen antelope.
Engine and Rotor RPM Issues
As the pilot initiated a 'quick-stop' maneuver, the engine began to lug down. In response, the pilot rolled on the throttle, overriding the governor, and simultaneously nosed the helicopter over while lowering the collective. The main rotor low rpm warning sounded around the time forward cyclic was applied. Although the helicopter was gaining airspeed, the rotor rpm continued to decline. The pilot attempted to 'milk' the collective but was unable to recover rotor rpm.
Hard Landing and Damage
At an altitude of approximately 3 to 5 feet above ground level, rotor rpm had dropped to 80 percent. The pilot leveled the helicopter and attempted a run-on landing. The helicopter landed hard, causing a main rotor blade to strike the tail boom. The impact separated the tail boom at its mid-length.