# Main rotor mast/swashplate - 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 mast/swashplate - NTSB code: 01046230 - Cases: 13 - In the probable cause: 12 - Fatal cases: 9 - All cases: https://openairdocs.org/ntsb-findings/01046230/cases.md - Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/01046230/cases.md?cause=1 - Page: https://openairdocs.org/ntsb-findings/01046230 ## Cases per year (in the probable cause / all) - 2010: 1 / 1 - 2011: 1 / 1 - 2012: 2 / 2 - 2013: 1 / 1 - 2014: 1 / 1 - 2015: 1 / 1 - 2016: 2 / 2 - 2021: 2 / 2 - 2022: 0 / 1 - 2024: 1 / 1 ## Defining events in these cases - [Mast bumping](https://openairdocs.org/ntsb-events/245): 3 cases - [Part(s) separation from AC](https://openairdocs.org/ntsb-events/338): 2 cases - [Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330): 2 cases - [Abrupt maneuver](https://openairdocs.org/ntsb-events/270): 2 cases - [Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340): 1 cases - [Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333): 1 cases - [Loss of control in flight](https://openairdocs.org/ntsb-events/240): 1 cases - [Unknown or undetermined](https://openairdocs.org/ntsb-events/000): 1 cases ## Aircraft models (registry) - [Robinson Helicopter R66](https://openairdocs.org/model/robinson-helicopter-r66): 2 cases - [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44): 2 cases - [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii): 1 cases - [Eurocopter Deutschland EC 135 P2+](https://openairdocs.org/model/eurocopter-deutschland-ec-135-p2-plus): 1 cases - [Garlick Helicopters UH-1H](https://openairdocs.org/model/garlick-helicopters-uh-1h): 1 cases - [Fairchild Hiller FH-1100](https://openairdocs.org/model/fairchild-hiller-fh-1100): 1 cases - [Arrow Falcon Exporters OH-58C](https://openairdocs.org/model/arrow-falcon-exporters-oh-58c): 1 cases - [Bell 222U](https://openairdocs.org/model/bell-222u): 1 cases - [Bell 214ST](https://openairdocs.org/model/bell-214st): 1 cases - [Bell OH-58A](https://openairdocs.org/model/bell-oh-58a): 1 cases ## Other findings in the same cases - [Not determined, general](https://openairdocs.org/ntsb-findings/05000000) (Not determined): 2 cases - [Terrain induced turbulence](https://openairdocs.org/ntsb-findings/03032010) (Environmental issues): 2 cases - [Aircraft control](https://openairdocs.org/ntsb-findings/02063040) (Personnel issues): 2 cases - [Replacement](https://openairdocs.org/ntsb-findings/02062020) (Personnel issues): 2 cases - [Incorrect action performance](https://openairdocs.org/ntsb-findings/02041015) (Personnel issues): 2 cases - [Convective turbulence](https://openairdocs.org/ntsb-findings/03032020) (Environmental issues): 1 cases - [Use of policy/procedure](https://openairdocs.org/ntsb-findings/02063032) (Personnel issues): 1 cases - [Use of equip/system](https://openairdocs.org/ntsb-findings/02063015) (Personnel issues): 1 cases - [Recent experience w/ equipment](https://openairdocs.org/ntsb-findings/02031045) (Personnel issues): 1 cases - [Motivation/respond to pressure](https://openairdocs.org/ntsb-findings/02021025) (Personnel issues): 1 cases ## Newest cases - [NTSB ANC24FA063](https://openairdocs.org/ntsb/ANC24FA063), Jul 11, 2024: Robinson Helicopter R44 (N144KW), Kekaha, HI, substantial damage, 3 fatal. Probable cause: An encounter with turbulence due to downdraft winds that resulted in mast bumping and an in-flight breakup. - [NTSB ERA22FA105](https://openairdocs.org/ntsb/ERA22FA105), Jan 11, 2022: Eurocopter Deutschland EC135 P2+ (N531LN), Drexel Hill, PA, substantial damage. Probable cause: An inflight attitude upset for undetermined reasons that resulted in a rotor system overspeed, a reduction of power from both engines, and a subsequent hard landing. - [NTSB ERA21FA317](https://openairdocs.org/ntsb/ERA21FA317), Aug 7, 2021: Rotorway Exec 162F (N162KJ), Argyle, NY, destroyed, 2 fatal. Probable cause: The pilot’s abrupt control inputs, which resulted in a low G condition, main rotor mast bumping, and the subsequent severing of the tail boom by a main rotor blade. - [NTSB WPR21FA300](https://openairdocs.org/ntsb/WPR21FA300), Aug 1, 2021: Robinson Helicopter R66 (N7000J), Colusa, CA, destroyed, 4 fatal. Probable cause: The pilot’s abrupt flight control input that led to mast bumping and a subsequent in-flight breakup. - [NTSB CEN17FA012](https://openairdocs.org/ntsb/CEN17FA012), Oct 6, 2016: Fairchild Hiller FH 1100 (N4035G), Lino Lakes, MN, destroyed, 2 fatal. Probable cause: The separation of the main rotor assembly due to mast bumping. - [NTSB WPR16FA130](https://openairdocs.org/ntsb/WPR16FA130), Jun 23, 2016: Robinson Helicopter R66 (N117TW), Wikieup, AZ, destroyed, 2 fatal. Probable cause: An encounter with turbulence due to updrafts and/or dust devils that resulted in mast bumping and an in-flight break-up. - [NTSB WPR15LA178](https://openairdocs.org/ntsb/WPR15LA178), May 31, 2015: Garlick Helicopters UH 1H (N462CC), Cove, OR, substantial damage. Probable cause: The failure of the engine-to-transmission drive shaft coupling assembly due to a fatigue fracture of one of its attachment bolts, which resulted in a loss of power to the main rotor. - [NTSB WPR15FA051](https://openairdocs.org/ntsb/WPR15FA051), Dec 2, 2014: Robinson Helicopter R44 (N3234U), Bountiful, UT, substantial damage, 2 fatal. Probable cause: The pilot/mechanic's failure to properly secure the pitch link hardware of one main rotor blade to the rotating swash plate, which resulted in the pitch link separating in flight and a subsequent… - [NTSB ERA13FA186](https://openairdocs.org/ntsb/ERA13FA186), Apr 3, 2013: Robinson R44 (N3101H), Miami, FL, destroyed, 2 fatal. Probable cause: The mechanic's failure to properly secure the pitch link hardware of one main rotor blade to the rotating swash plate, which resulted in the pitch link separating in flight and the pilot's subsequent… - [NTSB WPR12LA096](https://openairdocs.org/ntsb/WPR12LA096), Jan 21, 2012: Arrow Falcon Exporters OH-58A (N902SF), Brawley, CA, substantial damage. Probable cause: The failure of the main rotor mast due to fatigue cracks that originated from corrosion pits. Contributing to the accident was the operator’s failure to adhere to the manufacturer’s recommended… 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.