N690WAHughes Helicopters HUGHES 369D · 1978

The pilot reported that after landing at a remote landing zone (LZ) to pick up a single passenger, the passenger loaded their gear in the aft right seat and secured it with a seatbelt. While enroute, the two occupants heard a “loud and violent bang” and the nose of the helicopter moved to the right and vibrations followed. The pilot looked back at the tail rotor, saw it was spinning freely, and confirmed the tail rotor drive train had failed. The pilot performed an autorotation to an open field. A post flight inspection revealed that the passenger’s rain pants were missing from the aft right seat. It was determined that the rain pants had exited the helicopter and impacted the tail rotor resulting in substantial damage to the fuselage, tail boom, horizontal stabilizer and tail rotor assembly and gearbox. The pilot stated that there were no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation.