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Main rotor mast/swashplate

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NTSB finding · Aircraft › Aircraft propeller/rotor › Main rotor system

All 13 cases12 in the probable cause
Cases
13
In the probable cause
12 (92%)
Fatal cases
9
NTSB code
01046230

NTSB has coded findings and defining events since 2008. Earlier cases used its older occurrence and cause codes, so they aren’t counted here.

When and where

In green, cases where NTSB made it part of the probable cause; in gray, a factor or other finding. Findings are coded with the final report, often a year or more after the event, so the latest years are incomplete.

Cases per year

2008In the probable causeFactor only2026

Where

Open the map
Query with SQL
duckdb -csv -c "SELECT year(c.\"eventDate\") AS year, count(DISTINCT f.case_mkey) AS cases,
    count(DISTINCT f.case_mkey) FILTER (WHERE f.\"inProbableCause\") AS in_probable_cause
  FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' f JOIN 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c ON c.\"mKey\" = f.case_mkey
  WHERE starts_with(f.\"findingCode\", '01046230') AND c.\"eventDate\" >= DATE '2000-01-01'
  GROUP BY 1
  ORDER BY 1"

Prints the counts as CSV. It reads the release’s Parquet files over HTTPS, so there’s nothing to download first. Install DuckDB to run it.

In the same cases

Defining events
Aircraft models

Aircraft matched to the registry by N-number and date.

Other findings
Query with SQL
duckdb -csv -c "WITH matched AS (SELECT DISTINCT case_mkey, aircrafts_position FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' WHERE starts_with(\"findingCode\", '01046230'))
  SELECT * FROM (
  SELECT 'Defining event' AS kind, e.\"tier2Number\" AS code, max(e.\"eventTier2Name\") AS name, count(DISTINCT f.case_mkey) AS cases
  FROM matched f JOIN 'https://openairdocs.org/data/latest/ntsb_events.parquet' e ON e.case_mkey = f.case_mkey AND e.aircrafts_position = f.aircrafts_position AND e.\"isDefiningEvent\"
  WHERE e.\"tier2Number\" <> ''
  GROUP BY ALL
  UNION ALL
  SELECT 'Aircraft model', a.aircraft_model_code, any_value(concat_ws(' ', m.manufacturer, m.model)), count(DISTINCT f.case_mkey)
  FROM matched f JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = f.case_mkey AND a.position = f.aircrafts_position
  LEFT JOIN 'https://openairdocs.org/data/latest/faa_aircraft_model.parquet' m ON m.code = a.aircraft_model_code
  WHERE a.aircraft_model_code IS NOT NULL
  GROUP BY ALL
  UNION ALL
  SELECT 'Other finding', left(g.\"findingCode\", 8), max(g.\"tier4Name\"), count(DISTINCT g.case_mkey)
  FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' g
  WHERE g.case_mkey IN (SELECT case_mkey FROM matched) AND NOT starts_with(g.\"findingCode\", '01046230') AND g.\"findingCode\" GLOB '[0-9][0-9]*'
  GROUP BY ALL
  )
  QUALIFY row_number() OVER (PARTITION BY kind ORDER BY cases DESC) <= 10
  ORDER BY kind, cases DESC"

Prints the counts as CSV. It reads the release’s Parquet files over HTTPS, so there’s nothing to download first. Install DuckDB to run it.

Newest cases · 13

NTSB ANC24FA063Accident · 3 fatalClass 3 · FieldFinal reportRobinson Helicopter R44 · Kekaha, HIAn encounter with turbulence due to downdraft winds that resulted in mast bumping and an in-flight breakup.Jul 11, 2024 · N144KW · Substantial damageNTSB ERA22FA105Accident · Serious injuriesClass 3 · FieldFinal reportEurocopter Deutschland EC135 P2+ · Drexel Hill, PAAn 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.Jan 11, 2022 · N531LN · Substantial damageNTSB ERA21FA317Accident · 2 fatalClass 3 · FieldFinal reportRotorway Exec 162F · Argyle, NYThe 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.Aug 7, 2021 · N162KJ · DestroyedNTSB WPR21FA300Accident · 4 fatalClass 3 · FieldFinal reportRobinson Helicopter R66 · Colusa, CAThe pilot’s abrupt flight control input that led to mast bumping and a subsequent in-flight breakup.Aug 1, 2021 · N7000J · DestroyedNTSB CEN17FA012Accident · 2 fatalField investigationFinal reportFairchild Hiller FH 1100 · Lino Lakes, MNThe separation of the main rotor assembly due to mast bumping.Oct 6, 2016 · N4035G · DestroyedNTSB WPR16FA130Accident · 2 fatalField investigationFinal reportRobinson Helicopter R66 · Wikieup, AZAn encounter with turbulence due to updrafts and/or dust devils that resulted in mast bumping and an in-flight break-up.Jun 23, 2016 · N117TW · DestroyedNTSB WPR15LA178Accident · No injuriesLimited investigationFinal reportGarlick Helicopters UH 1H · Cove, ORThe 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.May 31, 2015 · N462CC · Substantial damageNTSB WPR15FA051Accident · 2 fatalField investigationFinal reportRobinson Helicopter R44 · Bountiful, UTThe 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 loss of control.Dec 2, 2014 · N3234U · Substantial damageNTSB ERA13FA186Accident · 2 fatalField investigationFinal reportRobinson R44 · Miami, FLThe 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 loss of control. Contributing to the accident was the…Apr 3, 2013 · N3101H · DestroyedNTSB WPR12LA096Accident · No injuriesLimited investigationFinal reportArrow Falcon Exporters OH-58A · Brawley, CAThe 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 overhaul interval for the main rotor mast.Jan 21, 2012 · N902SF · Substantial damage
See all 13 cases
Query with SQL
duckdb -csv -c "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\", '01046230'))
  ORDER BY c.\"eventDate\" DESC, c.\"ntsbNumber\" DESC"

Prints the whole list as CSV. It reads the release’s Parquet files over HTTPS, so there’s nothing to download first. Install DuckDB to run it.