HISTORY OF FLIGHT On August 14, 2005, at 1620 eastern daylight time, an MBB Eurocopter BK 117 B-1, N117US, registered to SunTrust Leasing Corp. doing business as CJ Systems Aviation Group, operating as a 14 CFR Part 91 air ambulance positioning flight, conducted an emergency landing after takeoff, and rolled over in Jacksonville, Florida. Visual meteorological conditions prevailed at the accident site and the pilot initiated flight following after takeoff. The helicopter sustained substantial damage. The commercial pilot, and two flight crewmembers were not injured. The flight originated from the University Hospital helipad, Jacksonville, Florida on August 14, 2005 at 1615. According to the pilot, after completing the before takeoff checklist, the helicopter departed the University Hospital helipad enroute to Middleburg, Florida. Approximately thirty seconds after takeoff, the pilot reported a loud noise, and the helicopter shuttered. The pilot attempted to gain forward airspeed to continue the flight on one engine, however after the helicopter cleared a set of power lines, the pilot decided to execute a precautionary landing into the backyard of a residential home. The pilot instructed the crew to prepare for landing. Upon touching down on what the pilot believed was a hedgerow, the helicopter rolled onto the right side. PERSONNEL INFORMATION Review of pilot records revealed that the pilot held a commercial pilot certificate with ratings for single, multi-engine land, airplane, and helicopter instrument. Review of medical records revealed the commercial pilot held a second-class medical certificate issued on April 7, 2004. Review of company records indicated that the pilot accumulated a total of 3230 flight hours in the BK-117, and a total flight time of 10440 flight hours. WRECKAGE AND IMPACT INFORMATION Examination of the wreckage site revealed that the helicopter was located approximately 100-yards from the University hospital helipad resting on its left side. The main rotor blades broke between 6 and 16 inches outboard of the pendulum weights. The tail rotor blades intact, and tail boom buckled on the lower surface aft of the attach fitting. Mechanical continuity was established between main and tail rotor assemblies. Mechanical control continuity was established with the cyclic, collective, and anti-torque controls. Throttle continuity was verified on both engines units. Movement of the cyclic stick resulted in appropriate movement of the rotor head. The main rotor head assembly was intact, and the swash-plate was intact, and the rotating star rotated smoothly. The main rotor system pitch links were found intact. The right landing skid was buckled and bent into the lower airframe of the helicopter. The fuel tanks were breached and the smell of fuel was observed at the wreckage site. Approximately 60-gallons of fuel was removed from the fuel tanks. The number one engine, part number LTS101-750B-1 was successfully tested no discrepancies were noted during the engine run-up. The number two engine, did not start, and after several maintenance items were checked, the engine still would not start. The Power Turbine Thrust Kit was removed and examined. Examination of the power turbine kit revealed the elbow assembly was pierced allowing pressure control air to escape. The retention nut was not fitted on the stub shaft, and the lock cup was fractured. Evidence of fretting corrosion was found in the housing.