# NTSB investigations: Main rotor head system

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 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 CEN16LA330](https://openairdocs.org/ntsb/CEN16LA330.md): Hiller UH 12D · Cokeville, WY · Accident · Minor injuries · Limited investigation · Final report · Aug 23, 2016 · N97TH · Substantial damage
  > Failure of the control rotor cuff due to fatigue.
- [NTSB GAA15CA258](https://openairdocs.org/ntsb/GAA15CA258.md): Airbus AS350 · Draper, UT · Accident · No injuries · Data collection · Final report · Sep 9, 2015 · N253HP · Substantial damage
  > The ground recovery team member's failure to secure a rescue rope during the helicopter loading process in steep terrain, resulting in the rope fouling the helicopter's main rotor system.
- [NTSB CEN14LA056](https://openairdocs.org/ntsb/CEN14LA056.md): Pearson Jon M Dragonfly · Anahuac, TX · Accident · 1 fatal · Limited investigation · Final report · Nov 16, 2013 · N975DF · Destroyed
  > The incorrect installation by the pilot, who was not a certificated mechanic or repairman, of the main rotor head bearing block, which resulted in the in-flight separation of the rotor head.
- [NTSB DCA12FA024](https://openairdocs.org/ntsb/DCA12FA024.md): Bell 214 · Camp Bastion, Afghanistan · Accident · 3 fatal · Field investigation · Final report · Jan 16, 2012 · N5748M · Destroyed
  > the overtravel of the collective sleeve, which led to a severe and sudden reduction in main rotor blade collective pitch, resulting in a loss of control of the helicopter. The reason for the collective sleeve overtravel could not be determined since much of…
- [NTSB CEN12FA001](https://openairdocs.org/ntsb/CEN12FA001.md): Robinson Helicopter R66 · Philip, SD · Accident · 1 fatal · Field investigation · Final report · Oct 1, 2011 · N266CY · Destroyed
  > The in-flight separation of the main rotor mast following a mast bumping event. The reason for the mast bumping event could not be determined due to postaccident damage.
- [NTSB CEN11FA422](https://openairdocs.org/ntsb/CEN11FA422.md): Robinson R22 Beta · Del Valle, TX · Accident · 1 fatal · Field investigation · Final report · Jun 27, 2011 · N7779M · Substantial damage
  > The divergence of the main rotor from its normal plane of rotation for reasons that cannot be determined because the pilot’s control inputs leading up to the event are unknown, resulting in mast bumping and main rotor blade separation.
- [NTSB WPR09LA253](https://openairdocs.org/ntsb/WPR09LA253.md): Gauchat Safari · Rock Springs, AZ · Accident · 2 fatal · Limited investigation · Final report · May 22, 2009 · N147MD · Substantial damage
  > The separation of the main rotor head during cruise flight as a result of cyclic fatigue of the main rotor head spindle. The fatigue crack was due to an inadequate manufacturing process.
- [NTSB MIA08LA199](https://openairdocs.org/ntsb/MIA08LA199.md): Eurocopter AS-350-BA · Linden, NJ · Accident · No injuries · Limited investigation · Final report · Sep 19, 2008 · N906BA · Substantial damage
  > The flight instructor’s delayed remedial action (flight control inputs) during a practice autorotation/run-on landing resulting in fracture damage to the main rotor system Starflex.
- [NTSB NYC08LA318](https://openairdocs.org/ntsb/NYC08LA318.md): Hiller UH-12E · Naruna, VA · Accident · No injuries · Limited investigation · Final report · Sep 16, 2008 · N3324F · Substantial damage
  > The fatigue failure of a main rotor blade drag strut.

## 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", '01046220'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-findings/01046220/cases

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