Bell 206L-3 N3174Y

While in cruise flight over open ocean water, the pilot of the air taxi helicopter heard a "bang," and the helicopter yawed. The pilot was unable to control the yaw, so he initiated an autorotation. Prior to water entry, the skid mounted floats were successfully deployed. After touchdown on the water, the helicopter rolled over inverted, and the pilot and passenger exited the helicopter and were rescued by a recovery boat. Examination of the wreckage revealed a main rotor blade contact mark just aft of the exhaust stack on a downward angle of approximately 45 degrees. Cyclic, collective, and tail rotor control continuity was established throughout the flight control system. Removal. of the tail rotor drive shaft cowling revealed that the #6 drive shaft (s/n VNMK-47448) twisted apart into two sections, with respective adjacent disc pack couplings deformed. The #8 drive shaft (s/n VNMKH-48083) was found twisted, but not separated, no deformity was noted on the adjacent disc pack couplings. One tail rotor blade (s/n CS-9003) showed damage to its leading edge, and was fractured along the chord in perpendicular to the leading edge. A "bluish", plastic appearing material was found smeared onto the damaged leading edge. The opposite tail rotor blade displayed no visible damage, however, some of the "bluish" coloration was found on its blade tip weight rivets. The tail boom showed evidence of scrapping along its left side, corresponding to the tip path plane of the tail rotor disc. Additional "bluish" coloration was present in the area of the scrapes, and on the tail rotor gearbox output shaft. All damage found was within the rotational arc of the tail rotor disc, with the exception of the exception the main rotor blade and the twisted #6 section of the tail rotor drive shaft. The baggage compartment door and latches were inspected for integrity. The door interior was not deformed and did not show visible evidence of impact marks and the latches were in good condition with no looseness when the door was in the closed & latched position. An electrical continuity check of the baggage door open warning system found no anomalies, and the caution panel bulbs were not damaged or burned. Additionally, neither the pilot or passenger reported noticing any warning lights being illuminated during the accident. All four passenger and crew doors were closed and latched, and would not open by normal means from inside the cabin. During recovery, examination, and interviews, some of the aircraft's standard on-board equipment and internal cargo that was loaded prior to take off were not found. Unoccupied Rear Cabin (5 seating positions): 3 personal flotation devices; 1 newspaper; 1 manila folder with contents. Baggage Compartment: 2 cardboard boxes, measuring 12 inches by 12 inches; 1 envelope; 1 plastic hard hat; 1 ice water cooler. Material analysis of the "bluish" marks on the tail rotor were not conclusive as to what type of object or material could have come into contact with the tail rotor during flight. No mechanical anomalies were discovered that could have contributed to the accident.

Quoted verbatim from the NTSB record.