What happened
A single-engine helicopter was performing a round-robin flight between two offshore oil platforms. During the return leg of the flight, the pilot experienced an unusual noise followed by pronounced roughness within the tail rotor system. Although the roughness decreased after several seconds and the pilot determined the tail rotor remained functional, the aircraft was landed safely.
Upon conducting a post-flight inspection, the pilot discovered a metal wire wrapped around both sides of the tail rotor. The pilot stated that a 3-foot-by-4-foot sunshade, intended to protect the cockpit windows, had departed the helicopter during the flight.
The investigation
Post-accident examination of the aircraft revealed structural damage to the tail rotor blades, the tail boom, and the lower portion of the vertical fin assembly, which included the tail skid. The investigation determined that the sunshade exited an open window because it had not been properly secured prior to takeoff, subsequently becoming entangled in the tail rotor system.