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Tail rotor drive system, general

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NTSB finding · Aircraft › Aircraft propeller/rotor › Tail rotor drive system

All 10 cases
Cases
10
In the probable cause
10 (100%)
Fatal cases
0
NTSB code
01046500

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\", '01046500') 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\", '01046500'))
  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\", '01046500') 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 · 10

NTSB ANC24LA077Accident · No injuriesClass 3 · LimitedFinal reportRobinson R44 · Honolulu, HIA failure of the flex plate yoke flange assembly due to incorrectly torqued bolts. Contributing was the maintenance personnel’s inadequate inspection of the tail rotor flex plate assembly.Aug 19, 2024 · N740RH · Substantial damageNTSB CEN19LA174Accident · No injuriesClass 3 · LimitedFinal reportRobinson R44 · Key West, FLThe failure of maintenance personnel to properly secure the right-side tail boom mounting bolts which resulted in the failure of the bolts and an inflight separation of the tail rotor.Jun 17, 2019 · N1241W · Substantial damageNTSB CEN19LA065Accident · Minor injuriesLimited investigationFinal reportRobinson R44 · Uvalde, TXThe slipping of the sprag clutch due to galling of the sprags and corresponding sprag contact surfaces within the clutch assembly, which rendered the helicopter uncontrollable.Jan 8, 2019 · N484AB · Substantial damageNTSB CEN18LA247Accident · Serious injuriesLimited investigationFinal reportSafari 400 · Aguilares, TXThe loss of tail rotor control due to the in-flight failure of the tail rotor pinion.Jul 2, 2018 · N326RW · Substantial damageNTSB CEN15LA379Accident · Minor injuriesLimited investigationFinal reportRobinson Helicopter R44 II · Ketchum, OKThe separation of the tail rotor gearbox from the tailboom aft bulkhead due to overstress loads imposed by a blade imbalance from an in-flight impact with an undetermined object.Aug 25, 2015 · N444KD · Substantial damageNTSB WPR14LA225Accident · No injuriesLimited investigationFinal reportEmery Mark Rotorway 162F · Merced, CAThe helicopter pilot/owner's decision to install a belt type not recommended by the kit manufacturer in the tail rotor drive system using the incorrect tension values, which led to the belt’s in-flight failure and the subsequent loss of tail rotor drive…Jun 4, 2014 · N78291 · DestroyedNTSB ERA12LA368Accident · No injuriesLimited investigationFinal reportSchweizer 269C · Piney Flats, TNThe mechanic’s improper maintenance of the main transmission aft pinion nut and belt drive system, which resulted in the uncoupling of the tail rotor driveshaft and the subsequent loss of helicopter control.May 24, 2012 · N760DA · Substantial damageNTSB CEN12LA181Accident · No injuriesLimited investigationFinal reportSikorsky 269C · Staples, TXThe pilot's failure to attain the proper descent rate during autorotation, which resulted in a hard landing. Contributing to the accident were the inflight vibrations and loss of torque pedal response for undetermined reasons.Mar 5, 2012 · N1099N · Substantial damageNTSB CEN11LA414Accident · No injuriesLimited investigationFinal reportEnstrom F-28C-2 · Blair, NEThe failure of a tail rotor pitch change link due to the retaining bolt becoming separated in flight. Contributing to the accident was the pilot’s inadequate preflight inspection.Jun 23, 2011 · N5694A · Substantial damageNTSB NYC08CA252Accident · Minor injuriesData collectionFinal reportBuschmann Robert E Helicycle · Stuart, FLThe pilot's improper decision to take off with a known discrepancy. Contributing to the accident was spilled fuel on the drive belts.Jul 19, 2008 · N3375C · Substantial damage
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\", '01046500'))
  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.