Incident Overview
On May 22, 2012, at approximately 1430 Pacific daylight time, a Eurocopter AS-350 B2 (registration N105TV) sustained minor damage following an in-flight separation of a tail rotor pitch change link bolt. The helicopter was maneuvering near Seattle-Tacoma International Airport (SEA) in Seattle, Washington, at the time. The airline transport pilot and aerial photographer crewmember were not injured.
Flight Details
The helicopter was registered to KING Broadcasting Company, Seattle, Washington, and operated as an electronic news gathering flight under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and a company flight plan was activated. The flight originated from Boeing Field (BFI), Seattle, Washington, about 1415, with a planned destination of Seattle Private Number One Heliport (WN01).
Pilot Report
The pilot reported that he had just entered a slow orbit at about 1,200 feet above ground when the helicopter experienced a severe vibration. The vibration was continuous and severe, prompting the pilot to divert to BFI for landing. The pilot noted that just before landing, with full right pedal inputs, the helicopter entered a slow left turn that continued until touchdown on a taxiway.
Postincident Examination
A postincident examination revealed damage to the tail boom assembly and support structure. The examination also determined that one of the tail rotor pitch change link bolts (to the pitch arm) was missing and had likely released during the flight. This release resulted in asymmetrical pitch between the two tail rotor blades, leading to the subsequent vibration.
Maintenance Background
The accident flight followed a 100-hour maintenance inspection that concluded earlier that day. The inspection included maintenance and service to the tail rotor assembly. The pilot reported that the pitch change link bolt (to pitch arm) was not correctly tightened and secured during the maintenance and subsequently loosened and released during the flight.