On June 8, 1996, at 1715 central daylight time, a Hughes 269 helicopter, N269A, was substantially damaged following a loss of control while attempting to hover at Addison Airport, Dallas, Texas. The certified flight instructor and student pilot were not injured. The helicopter was owned and operated by PSF Enterprises, Terrell, Texas. Visual meteorological conditions prevailed and no flight plan was filed for the Title 14 CFR Part 91 instructional flight. In a telephone interview and on NTSB Form 6120.1/2, the flight instructor reported the following information: The flight was pre-planned with the intent for the student pilot to practice hover related maneuvers. The practice area was a smooth, flat, grassy area on the west side of the airport, between the control tower and the runway. With the instructor pilot "riding the controls", the student pilot prepared to lift into a hover. The flight instructor stated that, the helicopter was "into the wind", the controls "appeared to feel correct", and control inputs were "slow, smooth, and deliberate." The aircraft "left the ground (not completely) right skid low", and began to roll to the right (the pilot stated that, he believed that the right skid did not break contact with the ground). Despite the instructor's application of left lateral cyclic, the craft continued to roll right, resulting in the main rotor blades contacting the ground. Subsequently, the helicopter came to rest on its right side. Examination of the helicopter by a FAA inspector revealed the following: Control lever positions; collective-"full up"; cyclic-"full right" (approximately centered forward & aft); Anti-torque pedals-"right pedal approximately 2 1/2 inches forward of left pedal." Mechanical control continuity was established from the cockpit controls to the main rotor and tail rotor assemblies, and no missing components were noticed. The main rotor mast was found fractured approximately 8 inches above the transmission mount plate, and just above the mast support attachment point. Several dark spots (possible corrosion) were observed in the mast cylinder at the lower portion of the fractured area; however, most of the fracture surface area indicated evidence of overload failure. There was no evidence of long term fatigue cracking. The main rotor blades showed evidence of contact with the ground (dirt deposits on the leading edges). The entire swashplate assembly and the main rotor pitch change links appeared to be intact with minimal damage. No mechanical anomalies were found that could have been a factor in the cause of the accident. The winds at the time of the accident were from 350 degrees at 20 knots, gusting to 30 knots.