NTSB CAROL · Event
Event DCA12MA020
Registry · N37SH
FAA Aircraft Registry record.
Make / Model
ZENITH CH650 XL ZENAIR
Year of manufacture
2024
Engine
VIKING 130 (130 hp)
Seats / Engines
2 seats · 1 engine
Last airworthiness date
20250917
ADS-B equipped
Yes — Mode-S A4330A
Registrant of record
HUBIN DAVID SCOTT
Source: FAA Aircraft Registry (releasable master file).
Aircraft involved
Probable cause & findings
Sundance Helicopters’ inadequate maintenance of the helicopter, including (1) the improper reuse of a degraded self-locking nut, (2) the improper or lack of installation of a split pin, and (3) inadequate postmaintenance inspections, which resulted in the in-flight separation of the servo control input rod from the fore/aft servo and rendered the helicopter uncontrollable. Contributing to the improper or lack of installation of the split pin was the mechanic’s fatigue and the lack of clearly delineated maintenance task steps to follow. Contributing to the inadequate postmaintenance inspection was the inspector’s fatigue and the lack of clearly delineated inspection steps to follow.
Factual narrative
The Safety Board’s full report is available at http://www.ntsb.gov/investigations/reports_aviation.html. The Aircraft Accident Report number is NTSB/AAR-13/01. On December 7, 2011, about 1630 Pacific standard time, a Sundance Helicopters, Inc., Eurocopter AS350-B2 helicopter, N37SH, operating as a “Twilight tour” sightseeing trip, crashed in mountainous terrain about 14 miles east of Las Vegas, Nevada. The pilot and four passengers were killed, and the helicopter was destroyed by impact forces and postimpact fire. The helicopter was registered to and operated by Sundance as a scheduled air tour flight under the provisions of 14 Code of Federal Regulations (CFR) Part 135. Visual meteorological conditions with good visibility and dusk light prevailed at the time of the accident, and the flight operated under visual flight rules. The helicopter originated from Las Vegas McCarran International Airport, Las Vegas, Nevada, about 1621 with an intended route of flight to the Hoover Dam area and return to the airport. The helicopter was not equipped, and was not required to be equipped, with any on board recording devices. The Safety Board’s full report is available at http://www.ntsb.gov/investigations/reports_aviation.html. The Aircraft Accident Report number is NTSB/AAR-13/01. On December 7, 2011, about 1630 Pacific standard time, a Sundance Helicopters, Inc., Eurocopter AS350-B2 helicopter, N37SH, operating as a “Twilight tour” sightseeing trip, crashed in mountainous terrain about 14 miles east of Las Vegas, Nevada. The pilot and four passengers were killed, and the helicopter was destroyed by impact forces and postimpact fire. The helicopter was registered to and operated by Sundance as a scheduled air tour flight under the provisions of 14 Code of Federal Regulations (CFR) Part 135. Visual meteorological conditions with good visibility and dusk light prevailed at the time of the accident, and the flight operated under visual flight rules. The helicopter originated from Las Vegas McCarran International Airport, Las Vegas, Nevada, about 1621 with an intended route of flight to the Hoover Dam area and return to the airport. The helicopter was not equipped, and was not required to be equipped, with any on board recording devices. 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 Aircraft-Aircraft propeller/rotor-Rotorcraft flight control-Rotorcraft servo system-Incorrect service/maintenance
- C Aircraft-Fluids/misc hardware-Misc hardware-Fasteners-Incorrect service/maintenance
- C Personnel issues-Task performance-Maintenance-Installation-Maintenance personnel
- C Personnel issues-Task performance-Inspection-Post maintenance inspection-Maintenance personnel
- C Aircraft-Aircraft propeller/rotor-Rotorcraft flight control-Rotorcraft servo system-Failure
- — Aircraft-Aircraft oper/perf/capability-Performance/control parameters-(general)-Attain/maintain not possible
- F Personnel issues-Physical-Alertness/Fatigue-(general)-Maintenance personnel
- F Organizational issues-Management-Policy/procedure-Availability of policy/proc-Operator
Verbatim from NTSB's published report. Source file
NTSB_2011_DCA12MA020.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 (stall, 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 2023 · Conference paper
The Value of Strong Partnerships to Build a Successful Aviation Maintenance Career Pathway Program for Transitioning Military Service Members
The aerospace industry is competing with other industries for a qualified workforce, and many of those competing industries are investing heavily in creating workforce development pipelines.
- 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…
- NASA NTRS 2026 · Conference Paper
Computational Analysis of Steady State Aerodynamics of Transonic Truss-Braced Wing Configuration in Deep Stall
This study presents a computational investigation of steady state aerodynamics of the Subsonic Ultra-Green Aircraft Research (SUGAR) Transonic Truss-Braced Wing (TTBW) configuration over a wide range …
- 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.
Browse the full corpus — academia portal ↗