FTW01LA172

After an uneventful flight, the pilot initiated an approach to an offshore platform into the wind, when the helicopter made an "uncontrolled, un-induced yaw to the right." He then attempted to turn to the right to stop the yaw and to maneuver away from the platform. As he increased power, the aircraft "went into an uncontrollable and rapid spin to the right." The pilot then closed the throttle and reduced power, which "slowed but did not stop the spin." Just as the pilot "pulled" collective, the aircraft impacted the water, rolled over, and sank. Flight control continuity checks were performed after the helicopter was recovered from the water. No anomalies were found within the tail rotor drive or flight control systems that could not be attributed to impact or recovery damage.

On August 5, 2001, approximately 0700 central daylight time, a Bell 206-L1 helicopter, N2755N, registered to and operated by Air Logistics L.L.C., of New Iberia, Louisiana, was substantially damaged when it impacted the water after a loss of control during approach to an offshore platform (West Cameron 173) in the Gulf of Mexico. The commercial pilot and his two passengers received serious injuries. Visual meteorological conditions prevailed and a company flight plan was filed for the 14 Code of Federal Regulations Part 135 on-demand air taxi flight. The flight originated from the company's Creole base, Creole, Louisiana, at 0630.

According to the pilot, after an uneventful flight from Creole, the pilot initiated an approach to the platform into the wind, when the helicopter made an "uncontrolled, un-induced yaw to the right." He then attempted to turn to the right to stop the yaw and to maneuver away from the platform. As he increased power, the aircraft "went into an uncontrollable and rapid spin to the right." The pilot then closed the throttle and reduced power, which "slowed but did not stop the spin." Just as the pilot "pulled" collective, the aircraft impacted the water, rolled over, and sank.

The wreckage was recovered from the water and examined at the operator's base in New Iberia, Louisiana, on August 7, 2001. Under the supervision of an FAA inspector, the pilot's and co-pilot's seats were removed and a flight control continuity check was performed from the anti-torque pedals rearward. All controls displayed freedom of movement and continuity existed rearward to the "broom closet" area. Within the "broom closet," one vertical control tube (tail rotor) was found fractured at the top, approximately 1 inch from the connecting clevis, at the base of the clevis shaft. Also, about 9 inches down the tube, was an impact mark. As the tail rotor control pedals were moved in the cockpit, there was corresponding movement of the control tube to the fractured point. The tail boom and tail rotor drive shaft were found fractured just aft of the tail boom attachment bulkhead. The remainder of the tail boom outer skin and the control tubes were cut as part of the recovery.

According to the recovery personnel, the tail boom and tail rotor drive shaft were fractured when the helicopter was pulled from the water, however, the tailboom was held to the fuselage by the tail rotor and elevator control tubes and the upper tail boom skin.

The tail rotor hub and blade assembly was attached to the tail rotor output shaft. The 90-degree gearbox was intact. Rotation of the input shaft to the 90-degree gearbox produced normal rotation of the hub and blade assembly. The hub was intact and the control linkages on the hub were intact. Examination of the tail rotor drive shaft assembly revealed multiple rotational scoring features on the shaft cover and where the drive shaft passes through the forward firewall. The tail rotor blades had minimal leading edge damage and were found slightly bent about 10-inches outboard from their respective blade roots.

No anomalies were found within the tail rotor drive or flight control systems that could not be attributed to impact or recovery damage.