On March 23, 1996, at 0832 eastern standard time, a Robinson R22-Beta, N221CW, was substantially damaged during a collision with terrain, while hovering at the Essex County Airport, Fairfield, New Jersey. The certified flight instructor and student pilot were not injured. Visual meteorological conditions prevailed for the instructional flight that originated at Essex County Airport (CDW), at 0810. No flight plan had been filed for the flight conducted under 14 CFR Part 91. In the certified flight instructor's (CFI) written statement, he said: "...The student had the controls and was making a landing from a hover. Winds were approximately 15 knots from the west. After landing, the helicopter made an immediate takeoff and drifted to the left rear with low rotor RPM light and horn...[I] immediately took the controls and attempted to increase throttle and stabilize the helicopter with cyclic input, but by that time the helicopter was uncontrollable. It then entered a 720 degree spin, settled to the ground and rolled onto it's left side..." According to the student pilot (SP), he was setting the helicopter down from a 3-foot-hover when the low RPM warning horn activated. The SP stated that the CFI then took over the controls. The SP further stated: "...The PIC tried to roll on throttle to get rotor RPM back in the green. He tried to pull back on the cyclic and the tail rotor hit the ground. The helicopter then did a 720 [degree turn] and hit the ground." Examination of the wreckage revealed no pre-impact failure of the helicopter controls or drive train. The tail rotor section, which included the blades, hub, gear box, and upper and lower vertical fins, were separated from the tail boom. These components were located about 50 feet northwest of the main wreckage. One tail rotor blade had separated from the hub. The main rotor blades were curved upwards and formed a bow shape.