SEA06LA135

The pilot reported that he was maneuvering the helicopter at an altitude of about 200 feet agl conducting filming operations when he heard a loud bang after which the collective control felt "mushy" and "as if there was no positive control." He initiated a precautionary power on autorotative landing. The helicopter touched down on top of a ridgeline and then slid approximately 50 to 75 feet into a gully area, coming to rest in a 40 to 45 degree nose down attitude. During the landing, the main rotor contacted and severed the tail boom. Examination of the helicopter revealed that the collective bungee support bracket was fractured. A service information notice issued by the helicopter's manufacturer on March 7, 1980, called for a one time inspection of the collective bungee support bracket to ensure that thickness of the machine web surface in the aft lug area of the bracket was 0.065 inch or more. Excerpts from the helicopter's maintenance records provided by the pilot indicated that the service information notice was complied with prior to June 25, 1997. Examination of the fractured bracket revealed that the web thickness varied from 0.036 to 0.052 inch, which was below the minimum thickness requirement. Additionally, a hole that would have been drilled in the bracket during compliance with the service information notice was not present, indicating the procedure was not performed.

On June 30, 2006, about 1730 mountain daylight time, a Hughes 369D helicopter, N369PB, sustained substantial damage during a precautionary autorotative landing on rough terrain in Castle Valley near Moab, Utah. The commercial pilot and the two crewmembers aboard the helicopter were not injured. The helicopter was registered to Helicopter Aviation Services and Leasing Inc. of Miami, Florida, and operated by Camera Copters Inc. of Miami. Visual meteorological conditions prevailed and a company flight plan was filed for the 14 CFR Part 91 business flight. The purpose of the flight was to film a ground event.

The pilot reported that he was maneuvering the helicopter at an altitude of about 200 feet agl conducting filming operations when he heard a loud bang after which the collective control felt "mushy" and "as if there was no positive control." He initiated a precautionary power on autorotative landing. The helicopter touched down on top of a ridgeline and then slid approximately 50 to 75 feet into a gully area, coming to rest in a 40 to 45 degree nose down attitude. During the landing, the main rotor contacted and severed the tail boom. Examination of the helicopter revealed that the collective bungee support bracket was fractured.

According to a representative of the manufacturer of the helicopter, the collective bungee helps maintain the pilot's selected collective pitch stick position in flight by counteracting forces that are fed back into the collective pitch stick. The collective bungee counteracts these forces so that collective stick loads are relatively constant throughout the full range of collective stick travel. Failure of the collective bungee bracket would not result in loss of use of the collective control. It would result in the pilot experiencing varying degrees of feedback forces to the collective stick depending on collective position.

The helicopter manufacturer's representative provided a copy of Service Information Notice No. DN-54.1 issued on March 7, 1980. The notice called for a one time inspection of the collective bungee support bracket to ensure that thickness of the machine web surface in the aft lug area of the bracket was 0.065 inch or more.

The pilot provided excerpts from the helicopter's maintenance records. According to the pilot, these excerpts detailed major repairs made to the helicopter in Canada. Examination of the excerpts revealed that an entry dated June 25, 1997, stated in part, "COLLECTIVE BUNGEE ASSY P/N 369D27371 INSTALLED (PREV CERT C-FOZW)." Additionally, the entry included "DN 54.1 COLLECTIVE TORQUE TUBE BRACKET" in a list of DNs that "were found to be previously complied with."

The fractured collective bungee support bracket was examined under the supervision of an FAA inspector at the helicopter manufacturer's facility in Mesa, Arizona. The examination revealed the following:

1. The collective bungee support bracket fractured due to fatigue emanating from one of the corners bracketing the recessed area on the machined web. No material anomalies were observed at the fatigue origin.

2. Hardness of the material was measured to be 79 HBS, which coincides with the hardness range typical for the material used to manufacture the part.

3. Service Information Notice DN-54.1 directed that a hole be drilled in the web to perform a measurement of the web thickness. No hole was present at the prescribed location in the bracket, indicating that the procedure was not performed.

4. The machined web, including coating thickness, varied from 0.036 to 0.052 inch thick at the fracture surface, below the minimum thickness requirement of 0.065 inch specified in Service Information Notice DN-54.1.