On July 17, 2006, about 1523 eastern daylight time, a Bell 206B, N515AA, registered to and operated by Anthony Leasing Inc., impacted with the ground at the Pompano Beach Airpark, Pompano Beach, Florida, during a Title 14 Code of Federal Regulations Part 91 maintenance check flight. Visual meteorological conditions prevailed and no flight plan was filed. The airline transport-rated pilot received minor injuries, and the helicopter incurred substantial damage. The flight was originating at the time of the accident. The pilot stated that he just completed a steep approach and elected to conduct another one. During the return toward the airport portion of the approach, at about 400 feet above the ground, the aircraft seemed to mush and feel sluggish to him. The helicopter had just had a two month long annual inspection and, during the preflight inspection, he noted minor issues during the hydraulic checks. With this in mind, he decided to discontinue the steep approach and fly to the landing spot on taxiway F. He wanted to increase the helicopter's airspeed to get "the aircraft on the ground A.S.A.P." There were no visual or auditoria warning indications from the helicopter instruments of a problem; however an unusual noise would not subside behind him. He elected to perform a run-on landing in the place of a flare to a quick stop arrival. Witnesses stated that the helicopter porpoised, hitting the ground nose first then the tail rotor, followed by the helicopter sliding on its side before stopping in the grassy area of the infield. The pilot exited the helicopter without assistance. A wreckage examination of the helicopter was conducted by representatives of the Bell Helicopter and the Rolls-Royce Corporation under NTSB oversight. Examination of the airframe, controls, rotor components, and landing gear revealed damage consistent with the observed ground scars and reported sequence of events. An air conditioner compressor in the aft lower portion of the engine compartment was observed with the belt off its pulley. Damages to the belt were consistent with it chafing against the nuts on the driveshaft Thomas coupling. An incorrect belt was installed and the pulleys were misaligned. The support bracket for the compressor was loose and had missing rivets. The Helicopter's maintenance records showed that the air conditioner compressor had a belt change and the base plate was re-shimmed to realign the driveshaft and the compressor during the annual inspection. Examination of the engine revealed the engine did not sustain any damage. Fuel was present throughout the fuel supply system to the fuel nozzle. There were no impediments to the air flow in the engine compressor inlet section. Airframe damage was consistent with a powered rotor system.