NTSB CAROL · Event
Event WPR12IA248
Aircraft involved
Probable cause & findings
Failure of maintenance personnel to ensure that the tail rotor pitch change link bolt was properly secured, which resulted in an in-flight separation of the bolt and subsequent vibration.
Factual narrative
On May 22, 2012, about 1430 Pacific daylight time, a Eurocopter AS-350 B2, N105TV, sustained minor damage following an in-flight separation of a tail rotor pitch change link bolt while maneuvering near the Seattle-Tacoma International Airport (SEA), Seattle, Washington. The airline transport pilot and aerial photographer crewmember were not injured. The helicopter was registered to KING Broadcasting Company, Seattle, Washington, and operated as an electronic news gathering flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and a company flight plan was activated for the flight that originated from Boeing Field (BFI), Seattle, Washington, about 1415. The pilot's planned destination was Seattle Private Number One Heliport (WN01). The pilot reported that he had just entered a slow orbit, about 1,200 feet above the ground, when the helicopter experienced what he described as a severe vibration. The vibration was continuous and so severe that the pilot diverted to BFI for landing. He reported that just before landing, with full right pedal inputs, the helicopter entered a slow turn to the left, which continued until touchdown on the taxiway. The pilot reported that a postincident examination of the helicopter revealed damage to the tail boom assembly and support structure. He reported the exam also revealed that one of the tail rotor pitch change link bolts (to the pitch arm) was missing and likely released during the flight, which resulted in an asymmetrical pitch between the two tail rotor blades and subsequent vibration. 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 while in maintenance and subsequently loosened and released during the flight. The pilot reported that he had just entered a slow orbit when the helicopter experienced what he described as a severe vibration. The vibration was continuous and so severe that the pilot diverted to a nearby airport and landed. Postincident examination of the helicopter revealed that one of the tail rotor pitch change link bolts (to the pitch arm) was missing. The incident 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 while in maintenance and subsequently loosened and released during the flight. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).
- C Personnel issues-Task performance-Maintenance-Scheduled/routine maintenance-Maintenance personnel - C
- C Aircraft-Fluids/misc hardware-Misc hardware-Fasteners-Incorrect service/maintenance - C
- C Aircraft-Aircraft propeller/rotor-Tail rotor-(general)-Malfunction - C
- C Aircraft-Aircraft handling/service-Maintenance/inspections-Scheduled maint checks-Incorrect service/maintenance - C
Verbatim from NTSB's published report. Source file
NTSB_2012_WPR12IA248.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (maintenance). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- Embry-Riddle Scholarly Commons 2026 · Journal article (IJAAA)
From Reactive to Predictive: A hybrid Trust-Mediated Adoption Framework for Data-Driven Maintenance in Distributed-Authority Aviation Environments
Modern aviation maintenance operates within increasingly data-intensive technological environments, yet the operational integration of predictive maintenance into routine decision-making remains incon…
- Semantic Scholar 2025 · Article (Applied Sciences)
Decision-Making Framework for Aviation Safety in Predictive Maintenance Strategies
The implementation of predictive maintenance (PM) in aviation presents unique challenges due to strict safety requirements, complex operational environments, and regulatory constraints.
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
Low-Resource Automatic Speech Recognition Domain Adaptation – A Case-Study in Aviation Maintenance
With timeliness and efficiency being critical in the aviation maintenance industry, the need has been growing for smart technological solutions that optimize and streamline the different underlying ta…
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
A New Trajectory in UAV Safety: Leveraging Reinforcement Learning for Distance Maintenance Under Wind Variations
In the field of aviation, safety is a critical cornerstone, and the operation of Unmanned Aerial Vehicle (UAV) systems is deeply connected with this principle.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Just Culture in Aviation: A Metaphorical Study on Aircraft Maintenance Students
Just Culture, a sub-dimension of safety culture, has been a prominent and debated topic in aviation safety in recent years.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Performance PRISM: A Comprehensive Framework For Performance Measurement In Aircraft Maintenance
Aircraft maintenance is governed by rigorous safety requirements and high operational complexity, demanding robust performance measurement frameworks to ensure optimal maintenance practices.
Browse the full corpus — academia portal ↗