On April 27, 2004, at 1130 central daylight time, a Bell 407 helicopter, N407BP, registered to Textron Financial Corp, of Wichita, Kansas, and operated by the Bell Training Academy, of Hurst, Texas, was substantially damaged during a practice autorotation at the Bell Helicopter Flight Training Facility (OTE2), near Hurst, Texas. The flight instructor (CFI) and the commercial pilot who was receiving recurrent training were not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 instructional flight. The local flight originated from OTE2 at 1030. The 13,200-hour CFI reported on the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that during the flight, the 1,413-hour pilot who was receiving instruction and was at the controls, initiated a practice, full-touchdown autorotation. During the cyclic "flare," just prior to touchdown, the helicopter’s pitch attitude became "excessively" nose high. Subsequently, the tailboom stinger struck the ground. The CFI stated that he was "unable to correct the aircraft attitude" before the stinger struck the ground. Examination of the helicopter by a Federal Aviation Administration inspector, who responded to the site of the accident, revealed that three of the five Thomas couplings on the tail-rotor drive shaft were compressed. Multiple wrinkles were observed along the length of the tail boom. The tail stinger was bent upward. The helicopter was operating normally during the flight, and post-accident examination of the flight controls did not reveal anamalies that could have contributed to the accident.