CEN10IA397

According to the pilot, the helicopter was on final approach to a platform in the Gulf of Mexico when he raised the collective to perform a go-around. However, the helicopter did not respond properly; rather, its performance and torque indications remained fixed at 45 percent. The pilot began a slow climb and diverted to a land-based airport at a cruise speed of about 60 knots. Because of a complete loss of collective pitch control, the pilot made a running landing on the runway at the airport, touching down about 45 knots. The helicopter came to a stop in the grass about 100 feet past the end of the runway. An examination of the helicopter revealed that several fasteners were missing from the top clevis of the collective control tube, which led to the control tube becoming disconnected from the collective pitch arm on the swash plate. The missing fasteners were found loose on the deck in the transmission compartment. Records showed that maintenance to reinstall the transmission and main rotor hub had been completed about 6 flight hours before the incident and that several mechanics and two pilots had examined the helicopter before the incident flight without noting the improperly secured/missing fasteners.

On July 12, 2010, about 1428 central daylight time, a Bell 206 L4 helicopter, N523RL, sustained minor damage after a flight control malfunction over the Gulf of Mexico approximately 62 miles south of Patterson, Louisiana. The commercial pilot and one passenger were not injured. The helicopter was owned and operated by Rotorcraft Leasing Company LLC, Broussard, Louisiana. A company flight plan had been filed for the 14 Code of Federal Regulations Part 135 passenger flight. Visual meteorological conditions prevailed at the time of the incident. The helicopter was attempting to land at a production platform in Eugene Island block 208-K after departing another platform approximately one mile away. According to the pilot, while on final approach to the platform, he raised the collective to perform a go-around, but the helicopter did not respond. The pilot noted that the helicopter performance and torque indication remained fixed at 45 percent. There were no abnormal noises, vibrations, or instrument indications. The pilot initiated a slow climb to 1,000 feet above ground level and diverted to Harry P. Williams Memorial Airport (PTN), Patterson, Louisiana, at a cruise speed of about 60 knots. On his first approach to runway 24, the pilot was not able to slow the helicopter and executed a go-around. On his second approach, with a complete loss of collective pitch control, the pilot made a successful running landing, touching down about 45 knots. The helicopter came to a stop in the grass about 100 feet past the end of the runway. The Federal Aviation Administration (FAA) inspectors who responded to the scene reported that the fasteners were missing from the top clevis of the collective control tube, mounted above the collective bellcrank. The control tube had subsequently become disconnected from the collective pitch arm on the swashplate. There was no deformation, bending, elongation, or damage in that area. The missing fasteners were found loose on the deck in the transmission compartment. Maintenance to reinstall the transmission and main rotor hub had been completed on July 7, 2010. Investigators were unable to establish why these fasteners were not properly secured, as several mechanics and pilots had examined the helicopter prior to the incident flight.