# Main rotor blade system - Type: NTSB finding subsection - Path: [Aircraft](https://openairdocs.org/ntsb-findings/01) › [Aircraft propeller/rotor](https://openairdocs.org/ntsb-findings/0104) › [Main rotor system](https://openairdocs.org/ntsb-findings/010462) › Main rotor blade system - NTSB code: 01046210 - Cases: 60 - In the probable cause: 51 - Fatal cases: 15 - All cases: https://openairdocs.org/ntsb-findings/01046210/cases.md - Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/01046210/cases.md?cause=1 - Page: https://openairdocs.org/ntsb-findings/01046210 ## Cases per year (in the probable cause / all) - 2008: 2 / 4 - 2009: 3 / 4 - 2010: 5 / 5 - 2011: 4 / 5 - 2012: 3 / 4 - 2013: 2 / 2 - 2014: 2 / 3 - 2015: 3 / 4 - 2016: 4 / 4 - 2017: 3 / 3 - 2018: 2 / 2 - 2019: 3 / 3 - 2020: 3 / 3 - 2021: 1 / 1 - 2022: 2 / 2 - 2023: 5 / 5 - 2024: 3 / 3 - 2025: 1 / 3 ## Defining events in these cases - [Loss of control in flight](https://openairdocs.org/ntsb-events/240): 8 cases - [Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330): 7 cases - [Part(s) separation from AC](https://openairdocs.org/ntsb-events/338): 6 cases - [Hard landing](https://openairdocs.org/ntsb-events/092): 6 cases - [Miscellaneous/other](https://openairdocs.org/ntsb-events/900): 5 cases - [Loss of lift](https://openairdocs.org/ntsb-events/500): 2 cases - [Aircraft structural failure](https://openairdocs.org/ntsb-events/337): 2 cases - [Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333): 2 cases - [Inflight upset](https://openairdocs.org/ntsb-events/271): 2 cases - [Abrupt maneuver](https://openairdocs.org/ntsb-events/270): 2 cases ## Aircraft models (registry) - [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta): 6 cases - [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d): 6 cases - [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii): 4 cases - [Eurocopter AS 350 B2](https://openairdocs.org/model/eurocopter-as-350-b2): 2 cases - [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44): 2 cases - [Enstrom F-28C](https://openairdocs.org/model/enstrom-f-28c): 2 cases - [Bell Helicopter Textron Canada 429](https://openairdocs.org/model/bell-helicopter-textron-canada-429): 2 cases - [Bell OH-58C](https://openairdocs.org/model/bell-oh-58c): 2 cases - [Bell 47D1](https://openairdocs.org/model/bell-47d1): 2 cases - [CSP Leasing CAVALON](https://openairdocs.org/model/csp-leasing-cavalon): 2 cases ## Other findings in the same cases - [Aircraft control](https://openairdocs.org/ntsb-findings/02063040) (Personnel issues): 16 cases - [Incorrect action performance](https://openairdocs.org/ntsb-findings/02041015) (Personnel issues): 6 cases - [Prop/rotor parameters](https://openairdocs.org/ntsb-findings/01062052) (Aircraft): 6 cases - [Not determined, general](https://openairdocs.org/ntsb-findings/05000000) (Not determined): 4 cases - [Use of equip/system](https://openairdocs.org/ntsb-findings/02063015) (Personnel issues): 4 cases - [Incorrect action selection](https://openairdocs.org/ntsb-findings/02041010) (Personnel issues): 4 cases - [Scheduled/routine inspection](https://openairdocs.org/ntsb-findings/02061520) (Personnel issues): 3 cases - [Monitoring environment](https://openairdocs.org/ntsb-findings/02021545) (Personnel issues): 3 cases - [Policy/procedure development](https://openairdocs.org/ntsb-findings/04011025) (Organizational issues): 2 cases - [Gusts](https://openairdocs.org/ntsb-findings/03034045) (Environmental issues): 2 cases ## Newest cases - [NTSB CEN26LA081](https://openairdocs.org/ntsb/CEN26LA081), Dec 23, 2025: Ela ELA10 (N396S), Morris, IL, substantial damage. Probable cause: The pilot’s failure obtain the proper rotor rpm before applying power for the takeoff roll which resulted in a loss of control. - [NTSB WPR25LA203](https://openairdocs.org/ntsb/WPR25LA203), Jul 6, 2025: Robinson Helicopter R44 (N715SG), Park City, UT, substantial damage. Probable cause: The pilot’s failure to maintain rotor rpm during an approach to landing in a mountainous area, which resulted in a collision with terrain. - [NTSB WPR25LA093](https://openairdocs.org/ntsb/WPR25LA093), Feb 13, 2025: Airbus Helicopters EC 130 T2 (N3WL), Moab, UT, substantial damage. Probable cause: The inflight collision with debris during takeoff. - [NTSB WPR25LA010](https://openairdocs.org/ntsb/WPR25LA010), Oct 9, 2024: Enstrom Helicopter 280C (N646H), Vale, OR, substantial damage. Probable cause: The pilot’s failure to maintain engine and rotor rpm during takeoff, that resulted in a hard landing. - [NTSB WPR24LA319](https://openairdocs.org/ntsb/WPR24LA319), Sep 26, 2024: Bell 206L (N9984K), Fern Prairie, WA, substantial damage. Probable cause: An aeroelastic interaction between the helicopter’s main rotor blades and nodal beam system, which resulted in oscillations that exceeded the design limits of the tailboom. Contributing to the… - [NTSB CEN24LA358](https://openairdocs.org/ntsb/CEN24LA358), Sep 11, 2024: Hughes 369 (N8969F), Canton, MI, substantial damage. Probable cause: Fatigue cracking of the main rotor blade that occurred at an undetermined time. - [NTSB WPR23LA313](https://openairdocs.org/ntsb/WPR23LA313), Aug 9, 2023: Bell OH-58A (N861CC), Guernsey, CA, substantial damage. Probable cause: The pilot’s overpitching of the main rotor blades while maneuvering at low altitude in a high-temperature environment at high gross weight, which resulted in a reduction of engine and rotor speed,… - [NTSB ERA23LA326](https://openairdocs.org/ntsb/ERA23LA326), Aug 5, 2023: Hughes 369 (N353AH), Elberon, VA, substantial damage. Probable cause: The pilot’s failure to maintain clearance from a power line structure arm, which resulted in main rotor blade contact. - [NTSB ERA23LA289](https://openairdocs.org/ntsb/ERA23LA289), Jun 27, 2023: Hughes 269A (N90270), Anderson, SC, substantial damage. Probable cause: The mechanics’ improper torquing of the main rotor blade dampers, which resulted in a ground resonance event during landing. - [NTSB CEN23LA199](https://openairdocs.org/ntsb/CEN23LA199), May 23, 2023: Bell Helicopter Textron Canada 407 (N451PH), Abbeville, LA, substantial damage. Probable cause: The pilot’s failure to maintain proper helicopter control during autorotation that resulted in an abnormal ground contact which caused the subsequent main rotor strike on the tail boom that severed… NTSB has coded findings and defining events since 2008; earlier cases used its older occurrence and cause codes and aren't counted. Findings: https://openairdocs.org/ntsb-findings.md. Defining events: https://openairdocs.org/ntsb-events.md. Phases of flight: https://openairdocs.org/ntsb-phases.md. Every investigation, filtered by finding, event, phase, state, year or model: https://openairdocs.org/ntsb.md (for example ?state=MI&fatal=1). NTSB's definitions: Accident and incident, 49 CFR 830.2 (https://www.ecfr.gov/current/title-49/subtitle-B/chapter-VIII/part-830/subpart-A/section-830.2), CICTT occurrence categories (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/OccurrenceCategoryDefinitions.pdf), CICTT phases of flight (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/PhaseofFlightDefinitions.pdf), and NTSB coding manual, before 2008 (PDF) (https://www.ntsb.gov/GILS/Documents/codman.pdf). NTSB publishes no definitions for its findings, only their names. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.