# Aircraft propeller/rotor - Type: NTSB finding subcategory - Path: [Aircraft](https://openairdocs.org/ntsb-findings/01) › Aircraft propeller/rotor - NTSB code: 0104 - Cases: 476 - In the probable cause: 432 - Fatal cases: 95 - All cases: https://openairdocs.org/ntsb-findings/0104/cases.md - Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/0104/cases.md?cause=1 - Page: https://openairdocs.org/ntsb-findings/0104 ## Cases per year (in the probable cause / all) - 2008: 45 / 50 - 2009: 24 / 27 - 2010: 26 / 28 - 2011: 34 / 38 - 2012: 34 / 39 - 2013: 24 / 26 - 2014: 20 / 26 - 2015: 38 / 43 - 2016: 24 / 25 - 2017: 20 / 21 - 2018: 21 / 21 - 2019: 22 / 22 - 2020: 18 / 20 - 2021: 15 / 17 - 2022: 19 / 21 - 2023: 19 / 20 - 2024: 23 / 24 - 2025: 6 / 8 ## Sections - [Propeller system](https://openairdocs.org/ntsb-findings/010461): 177 cases, 165 in the probable cause - [Main rotor system](https://openairdocs.org/ntsb-findings/010462): 104 cases, 92 in the probable cause - [Rotorcraft flight control](https://openairdocs.org/ntsb-findings/010467): 56 cases, 53 in the probable cause - [Tail rotor](https://openairdocs.org/ntsb-findings/010464): 54 cases, 46 in the probable cause - [Tail rotor drive system](https://openairdocs.org/ntsb-findings/010465): 46 cases, 41 in the probable cause - [Main rotor drive](https://openairdocs.org/ntsb-findings/010463): 44 cases, 41 in the probable cause - [Aircraft propeller/rotor, general](https://openairdocs.org/ntsb-findings/010400): 11 cases, 7 in the probable cause ## Defining events in these cases - [Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330): 76 cases - [Part(s) separation from AC](https://openairdocs.org/ntsb-events/338): 73 cases - [Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340): 57 cases - [Loss of control in flight](https://openairdocs.org/ntsb-events/240): 46 cases - [Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333): 39 cases - [Miscellaneous/other](https://openairdocs.org/ntsb-events/900): 24 cases - [Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342): 19 cases - [Loss of engine power (total)](https://openairdocs.org/ntsb-events/341): 17 cases - [Hard landing](https://openairdocs.org/ntsb-events/092): 15 cases - [Unknown or undetermined](https://openairdocs.org/ntsb-events/000): 9 cases ## Aircraft models (registry) - [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta): 17 cases - [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii): 16 cases - [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44): 14 cases - [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d): 13 cases - [Bell 206B](https://openairdocs.org/model/bell-206b): 11 cases - [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e): 8 cases - [Bell 407](https://openairdocs.org/model/bell-407): 5 cases - [Bell Helicopter Textron 206L-1](https://openairdocs.org/model/bell-helicopter-textron-206l-1): 5 cases - [Eurocopter AS 350 B2](https://openairdocs.org/model/eurocopter-as-350-b2): 4 cases - [Eurocopter Deutschland EC 135 P2+](https://openairdocs.org/model/eurocopter-deutschland-ec-135-p2-plus): 4 cases ## Other findings in the same cases - [Aircraft control](https://openairdocs.org/ntsb-findings/02063040) (Personnel issues): 72 cases - [Not determined, general](https://openairdocs.org/ntsb-findings/05000000) (Not determined): 42 cases - [Use of equip/system](https://openairdocs.org/ntsb-findings/02063015) (Personnel issues): 32 cases - [Installation](https://openairdocs.org/ntsb-findings/02062035) (Personnel issues): 32 cases - [Decision making/judgment](https://openairdocs.org/ntsb-findings/02041520) (Personnel issues): 32 cases - [Incorrect action performance](https://openairdocs.org/ntsb-findings/02041015) (Personnel issues): 27 cases - [Scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010) (Personnel issues): 24 cases - [Airspeed](https://openairdocs.org/ntsb-findings/01062010) (Aircraft): 19 cases - [Performance/control parameters, general](https://openairdocs.org/ntsb-findings/01062000) (Aircraft): 19 cases - [Delayed action](https://openairdocs.org/ntsb-findings/02041025) (Personnel issues): 17 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 WPR26LA062](https://openairdocs.org/ntsb/WPR26LA062), Dec 15, 2025: Bell 407 (N404LL), Las Vegas, NV, substantial damage. Probable cause: Tail rotor blade impact from an unidentified object at an undetermined time. - [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 ERA25LA236](https://openairdocs.org/ntsb/ERA25LA236), Jun 20, 2025: Sting Sport TL-2000 (N878N), Dunavant, VA, substantial damage. Probable cause: The inflight failure of the propeller due to its exceedance of the manufacturer’s overhaul requirement. - [NTSB ANC25LA028](https://openairdocs.org/ntsb/ANC25LA028), Mar 27, 2025: Piper PA-28-140 (N261FC), Royal Kunia, HI, substantial damage. Probable cause: Improper alteration of the crankshaft propeller flange at an unknown time, which resulted in an in-flight separation of the propeller assembly. - [NTSB CEN25LA117](https://openairdocs.org/ntsb/CEN25LA117), Mar 10, 2025: Vans RV-7A (N923ZA), Plainview, TX, substantial damage. Probable cause: The improper machining of the propeller blade bearing seat, which resulted in an inflight propeller blade fatigue failure. Contributing to the accident was the improper machining of the propeller hub… - [NTSB WPR25LA096](https://openairdocs.org/ntsb/WPR25LA096), Feb 16, 2025: Cessna 150J (N151GW), Minersville, UT, substantial damage. Probable cause: The failure of the propeller blade due to fatigue that originated from an impact pit sustained at an unknown time. Contributing to the accident was the failure of unknown maintenance personnel to… - [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 ERA25LA040](https://openairdocs.org/ntsb/ERA25LA040), Nov 5, 2024: Hughes 369D (N11AS), Waycross, GA, substantial damage. Probable cause: An encounter with a foreign object, which resulted in a loss of control and collision with terrain. - [NTSB CEN25LA013](https://openairdocs.org/ntsb/CEN25LA013), Oct 11, 2024: Rotorway Exec (N314AC), Plymouth, IN, substantial damage. Probable cause: A loss of control due to the failed forward tail rotor belt as a result of the owner’s failure to follow the helicopter manufacturer’s tail rotor belt replacement recommendations. 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.