20060419004609A

(-23) On April 19, 2006, a Sikorsky sk 76-A, N8063R, departed on a flight from high island A-139 to west Houston airport (kiws), TX, at approximately 16:52, with 8 passengers and 2 flight crew members. Visual meteorological conditions prevailed at the time of departure and a flight plan was not filed for the 14 CFR part 135 flight. The aircraft made the approach to the north side of the west ramp from the north east, started a hover taxi towards the south taxiway on the west ramp via the parallel taxiway. The aircraft made a right pedal turn and was facing the terminal building on the south taxiway when the pilot lost tail rotor effectiveness. After about two or three 360 degree turns the aircraft and the rotorblades made contact with the ground and the aircraft came to a rest on its left side with the left gear bent underneath the belly of the aircraft. Inspectors opened the engine cowling to inspect the tail rotor drive shaft. Inspectors saw that the stainless steel cover over the drive shaft between the engines was not secured. The cover was contacting and rubbing against the tail rotor drive shaft. The aft portion of the cover was pushed over to the right hand engine side. A rip in the cowling was noticed on the left hand side of the drive shaft cover between the 3rd and 4th dzus fastener holes. Heat discoloration on the cowling was observed in that same location. Inspectors observed that none of the 10 dzus fasteners that secure the drive shaft cover were attached to the lower support structure of the drive shaft tunnel. Inspectors noticed large amounts of aluminum dust covering both engines and in the engine compartment area. The tail rotor drive shaft showed signs of heavy scoring from rubbing with the stainless steel drive shaft cowling. When the inspectors removed the drive shaft cowling from the drive shaft, a 1/8 cut completely through the drive shaft was found. Inspectors rotated the tail rotor blade assembly and found that drive shaft forward of the cut did not rotate. The inspectors photographed the entire process from the time the engine cowling was open to the time the cover was removed from the drive shaft. Inspectors found one of the dzus fasteners lying in the right hand engine area deck drain. The fastener shows signs of rubbing and wear marks on the collar. The cut on the tail rotor drive shaft matched up with a rivet that held the left hand, number one spring for the dzus fastener in place. The rivet, inside the cowling shows an extreme amount of rubbing on it with heat discoloring on the inside of the drive shaft cowling.