# NTSB investigations: Main rotor system, general

NTSB aviation accident and incident investigations since 1962: the probable cause, findings, aircraft, crew, weather and docket of each, linked to the FAA registry and the FAA’s own reports.

## Latest cases

- [NTSB WPR25LA010](https://openairdocs.org/ntsb/WPR25LA010.md): Enstrom Helicopter 280C · Vale, OR · Accident · No injuries · Class 4 · Limited · Final report · Oct 9, 2024 · N646H · Substantial damage
  > The pilot’s failure to maintain engine and rotor rpm during takeoff, that resulted in a hard landing.
- [NTSB CEN24LA013](https://openairdocs.org/ntsb/CEN24LA013.md): Magni M24 · Mount Sterling, IL · Accident · No injuries · Class 3 · Limited · Final report · Oct 16, 2023 · N90HM · Substantial damage
  > The pilot’s failure to maintain gyroplane control on the downwind leg, which resulted in impact with terrain. Contributing to the accident was the pilot’s distraction.
- [NTSB CEN22LA318](https://openairdocs.org/ntsb/CEN22LA318.md): Hiller UH12E · Becker, MN · Accident · Serious injuries · Class 3 · Limited · Final report · Jul 6, 2022 · N64272 · Substantial damage
  > The in-flight failure of the main rotor mast hub due to several undetected fatigue fractures.
- [NTSB ERA21LA126](https://openairdocs.org/ntsb/ERA21LA126.md): Bell 206 · Pahokee, FL · Accident · No injuries · Class 3 · Limited · Final report · Feb 4, 2021 · N820H · Substantial damage
  > A loss of main rotor rpm for reasons that could not be determined, which resulted in an autorotation and a subsequent hard landing and rollover.
- [NTSB ERA17LA257](https://openairdocs.org/ntsb/ERA17LA257.md): Robinson Helicopter R44 · Myrtle Beach, SC · Accident · No injuries · Limited investigation · Final report · Jul 24, 2017 · N828RD · Substantial damage
  > A loss of available power to the main rotor due to a fractured exhaust pushrod and housing, which allowed engine oil to coat the V-belts. Contributing to the accident was the pilot's decision to continue the tour and his failure to maintain adequate rotor rpm…
- [NTSB WPR16LA069](https://openairdocs.org/ntsb/WPR16LA069.md): Bell 47G 3B 1 · Carson City, NV · Accident · Minor injuries · Limited investigation · Final report · Feb 13, 2016 · N1181W · Substantial damage
  > The pilot's failure to maintain sufficient main rotor rpm, which resulted in a loss of helicopter control and a dynamic rollover.
- [NTSB CEN16LA040](https://openairdocs.org/ntsb/CEN16LA040.md): Robinson Helicopter R22 Beta · Sugarland, TX · Accident · Minor injuries · Limited investigation · Final report · Nov 14, 2015 · N7058Z · Substantial damage
  > The overspeed of the main rotor system for reasons that could not be determined based on the available information.
- [NTSB GAA15LA191](https://openairdocs.org/ntsb/GAA15LA191.md): Celier Xenon RST · Livingston, TX · Accident · Minor injuries · Limited investigation · Final report · Jul 17, 2015 · N402ED · Substantial damage
  > The pilot’s loss of directional control after aborting the takeoff due to a grinding noise coming from the main rotor area, which resulted in a runway excursion.
- [NTSB WPR15LA178](https://openairdocs.org/ntsb/WPR15LA178.md): Garlick Helicopters UH 1H · Cove, OR · Accident · No injuries · Limited investigation · Final report · May 31, 2015 · N462CC · Substantial damage
  > 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 CEN15FA126](https://openairdocs.org/ntsb/CEN15FA126.md): Enstrom 280FX · Erie, CO · Accident · 2 fatal · Field investigation · Final report · Jan 26, 2015 · N86235 · Destroyed
  > An in-flight failure of the helicopter's #2 main rotor spindle due to undetected fatigue cracking, which resulted in an in-flight breakup. Contributing to failure were the nonconforming thread root radius of the spindle and the manufacturer's failure to…
- [NTSB CEN14LA465](https://openairdocs.org/ntsb/CEN14LA465.md): Bell 206B · Spring, TX · Accident · No injuries · Limited investigation · Final report · Jul 30, 2014 · N866H · Substantial damage
  > The pilot's distraction by a cell phone call, which led to his failure to perform an exterior check of the helicopter and resulted in a tie-down strap remaining attached to the main rotor during the engine start.
- [NTSB WPR13FA417](https://openairdocs.org/ntsb/WPR13FA417.md): Bell UH-1V · Cordes Lakes, AZ · Accident · 2 fatal · Field investigation · Final report · Sep 21, 2013 · N22490 · Destroyed
  > The pilot's improper maintenance on the helicopter’s main rotor blade pitch control system, which resulted in an in-flight loss of main rotor blade pitch control, mast bumping, and mast failure.
- [NTSB CEN13LA437](https://openairdocs.org/ntsb/CEN13LA437.md): Enstrom F-28A · Danbury, TX · Accident · Serious injuries · Limited investigation · Final report · Jul 26, 2013 · N287Q · Substantial damage
  > The loss of collective control for reasons that could not be determined due to extensive fire damage.
- [NTSB ERA13FA273](https://openairdocs.org/ntsb/ERA13FA273.md): Bell Helicopter Textron 206L-1 · Manchester, KY · Accident · 3 fatal · Field investigation · Final report · Jun 7, 2013 · N114AE · Destroyed
  > The pilot’s loss of helicopter control due to spatial disorientation when he inadvertently encountered night, instrument meteorological conditions, which resulted in the in-flight separation of the main rotor and tailboom.
- [NTSB WPR13FA243](https://openairdocs.org/ntsb/WPR13FA243.md): Hiller UH-12E · Wenatchee, WA · Accident · Minor injuries · Field investigation · Final report · May 26, 2013 · N99090 · Substantial damage
  > Fatigue failure of the six bolts that secured the bevel gear to the first stage planetary carrier, which caused the transmission to seize while the helicopter and main rotor were still operating.
- [NTSB ERA12TA538](https://openairdocs.org/ntsb/ERA12TA538.md): Bell 407 · Bath, NY · Accident · Minor injuries · Final report · Aug 31, 2012 · N11SP · Substantial damage
  > The pilot's improper recovery from an in-flight upset, which resulted in the main rotor striking and separating the tail boom. Contributing to the accident was the helicopter manufacturer's failure to warn pilots of unanticipated and unequal aft cyclic…
- [NTSB WPR12LA219](https://openairdocs.org/ntsb/WPR12LA219.md): Enstrom F28 · Twin Falls, ID · Accident · No injuries · Limited investigation · Final report · May 20, 2012 · N63VP · Substantial damage
  > The pilot's inability to maintain helicopter control during cruise flight due to the failure of the No. 2 main rotor Lamiflex bearing. Contributing to the accident was the pilot's decision to operate the helicopter with a known deficiency and the helicopter’s…
- [NTSB WPR12LA039](https://openairdocs.org/ntsb/WPR12LA039.md): Williams Helicopter UH-1H · Grand Canyon, AZ · Accident · Serious injuries · Limited investigation · Final report · Nov 15, 2011 · N502AW · Substantial damage
  > The loss of main rotor power due to a main rotor transmission failure from a lack of lubrication.
- [NTSB CEN11GA218](https://openairdocs.org/ntsb/CEN11GA218.md): Hughes 369D · Meeker, CO · Accident · Minor injuries · Final report · Mar 8, 2011 · N131AL · Substantial damage
  > Main rotor contact with the tail boom resulting in tail boom separation.
- [NTSB CEN10FA509](https://openairdocs.org/ntsb/CEN10FA509.md): Bell Helicopter Textron 206L-1 · Walnut Grove, AR · Accident · 3 fatal · Field investigation · Final report · Aug 31, 2010 · N62AE · Substantial damage
  > The pilot’s loss of aircraft control, due to spatial disorientation, resulting in the in-flight separation of the main rotor and tail boom.
- [NTSB CEN10IA438](https://openairdocs.org/ntsb/CEN10IA438.md): Bell 206 · Gulf of Mexico, LA · Incident · No injuries · Incident investigation · Final report · Jul 26, 2010 · N317RL · Minor damage
  > The loss of main rotor rpm during takeoff for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies.
- [NTSB WPR09LA184](https://openairdocs.org/ntsb/WPR09LA184.md): Sikorsky CH-54B · Corvallis, OR · Accident · No injuries · Limited investigation · Final report · Apr 7, 2009 · N719HT · Substantial damage
  > The improper assembly of main rotor blade control components by the operator's maintenance personnel, which resulted in the main rotor blade's divergent path and their contact with the tail rotor drive shaft during ground operation following landing.
- [NTSB ERA09LA107](https://openairdocs.org/ntsb/ERA09LA107.md): Moore David DM-1 · Salters, SC · Accident · Minor injuries · Limited investigation · Final report · Dec 25, 2008 · N75EW · Substantial damage
  > A hard landing following an autorotation that resulted from the separation of the red main rotor blade cap that led to the uncontrolled movement of the cyclic, autorotation and a hard landing.
- [NTSB ANC08LA083](https://openairdocs.org/ntsb/ANC08LA083.md): Bell UH-1B · Iliamna, AK · Accident · No injuries · Limited investigation · Final report · Jun 30, 2008 · N64RA · Substantial damage
  > The failure of company maintenance personnel to ensure the helicopter was properly maintained, resulting in a severe in-flight vibration due to collective bounce. Contributing to the accident was loose and worn bearings on the helicopter's stabilizer bar,…
- [NTSB MIA08LA106](https://openairdocs.org/ntsb/MIA08LA106.md): Eurocopter France AS350 B2 · Hiram, GA · Accident · No injuries · Limited investigation · Final report · May 21, 2008 · N417AE · Substantial damage
  > The failure of the starflex arm during engine run-up due to inadequate inspection by maintenance personnel.

## The whole list in SQL

Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS:

```sql
SELECT c."ntsbNumber", c."eventDate", c."eventType", c."eventCity", c."eventStateOrRegion", a.n_number, a."aircraftMake", a."aircraftModel", c."highestInjuryLevel", c."totalFatal", c."completionStatus", c.report_url
FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = c."mKey" AND a.position = 1
WHERE c."mKey" IN (SELECT f.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' f WHERE starts_with(f."findingCode", '01046200'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-findings/01046200/cases

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