On October 2, 1997, at 1440 central daylight time, a Bell 206B helicopter, N2163Y, registered to Flight Safety International, Inc., and operated by Petroleum Helicopter, Inc., as a Title 14 CFR Part 91 instructional flight, was substantially damaged during a practice autorotational landing at the Acadiana Regional Airport, New Iberia, Louisiana. The flight instructor sustained minor injuries, and the commercial pilot was not injured. Visual meteorological conditions prevailed, and a company flight plan was filed. The flight originated from the Lafayette Regional Airport, Lafayette, Louisiana, about 40 minutes prior to the accident. According to the operator, the flight instructor was demonstrating an autorotation with a 180 degree turn to the sod area adjacent to Seaway 34. The operator added that "the winds were variable, but were generally aligned with the landing direction." The fight instructor reported to the operator that "the aircraft touched down with only slight forward speed in a slightly nose low attitude." Following touchdown, the helicopter began pitching over on its nose and the flight instructor applied "slight downward collective." Subsequently, the helicopter nosed over, the main rotor blades contacted the ground ,and the helicopter came to rest on its left side. The commercial pilot receiving instruction stated in the narrative portion of the NTSB Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), that the aircraft touched down smoothly in a level attitude. He added that "we were carrying 5 to 10 knots forward speed" during the landing. Examination of the aircraft by the FAA inspector revealed that the tailboom was separated at the fuselage, the airframe sustained structural damage, and the main rotor and tail rotor blades were damaged. The FAA inspector confirmed that the ground was very soft and this condition contributed to the skids of the helicopter to dig into the soft ground, resulting in the helicopter to nose over. The FAA inspector recommended that the local helicopter operators to discontinue using the sod area for running landings and autorotations until the sod area is hard enough to practice running landing.