On July 6, 2003, at 1430 Hawaiian standard time, a Robinson R22 Beta, N8318A, made a hard landing during a practice autorotation at Waimea 'Kohala Airport (MUE), Waimea, Hawaii. Hawaii Pacific Aviation, Inc., was operating the helicopter under the provisions of 14 CFR Part 91. The certified flight instructor (CFI) and the student were not injured; the helicopter sustained substantial damage. The local area instructional flight departed Kona International Airport (KOA), Kona, Hawaii, about 1330. Visual meteorological conditions prevailed and no flight plan had been filed. The CFI reported the purpose of the flight was to prepare the student for a commercial flight test the following day. After a series of maneuvers, they stopped the flight for a break and for additional fuel. After the break, two 180-degree autorotations from 1,000 feet above ground level (agl) were completed. Then they completed a 180-degree autorotation from 700 feet agl uneventfully. During a second 180-degree autorotation, about 100 feet agl at 70 knots, the CFI felt a sudden increase in the descent rate. He called for a go-around and assisted on the controls by adding throttle; however, the helicopter did not respond. The helicopter impacted the runway in a level attitude; the skids were "spread completely." During the descent, the rpm remained "in the green" and the low rotor rpm horn did not activate. The wind conditions reported by the CFI at the airport were 040 at 20 knots, gusting to 28 knots. The closest official weather reporting station is the Kona airport, which is located 26 miles southwest of the accident site. While there are no intervening topographical features between Kona and the accident site, the Waimea-Kohala airport is at the base of Mauna Kea mountain. At 1454, the winds were 230 degrees at 10 knots, while the 1353 report showed winds from 200 degrees at 12 knots. The winds reported on the METAR observations 3 hours each side of the accident time were from the southwest at generally 10 to 15 knots. No mechanical problems were noted with the helicopter prior to the accident.