OpenAirDocs.org

Reduction gear and shaft

Open the Markdown

NTSB finding · Aircraft › Aircraft power plant › Engine (turbine/turboprop)

All 8 cases
Cases
8
In the probable cause
8 (100%)
Fatal cases
0
NTSB code
01057210

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\", '01057210') 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\", '01057210'))
  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\", '01057210') 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 · 8

NTSB ERA23LA327Accident · No injuriesClass 3 · LimitedFinal reportAir Tractor AT502 · Leipsic, OHThe incorrect assembly of the turbine engine’s reduction gear box second-stage ring gear, which resulted in an internal failure of multiple engine components and a total loss of power.Aug 4, 2023 · N5048S · Substantial damageNTSB ENG23LA034Incident · No injuriesClass 3 · LimitedFinal reportHall Lester R Legacy · Rochester, MNMechanically distressed reduction gears causing an engine overspeed and turbine blade tensile overload and subsequent uncontainment. Contributing to the uncontainment was the operator’s use of the engine after knowingly purchasing the engine in an…Jul 20, 2023 · N707MM · Minor damageNTSB DCA12IA114Incident · No injuriesIncident investigationFinal reportBoeing 787 · Charleston, SCThe separation of the fan mid shaft resulted from environmentally assisted cracking under static load. Contributing to the incident was the combination of dry film lubricant applied to the fan mid-shaft and graphite grease used during assembly which made the…Jul 28, 2012 · VT-ANJ · Minor damageNTSB CEN11LA404Accident · Minor injuriesLimited investigationFinal reportAyres S2R-T34 · Athleimer, ARFailure of the first stage planetary gearset in the propeller reduction gearbox, which resulted in catastrophic engine failure. Contributing to the failure was the misrepresentation of the gearset being zero-timed by the company that sold the gearset to the…Jun 16, 2011 · N30902 · Substantial damageNTSB ENG11IA032Incident · No injuriesIncident investigationFinal reportDehavilland DHC-6-300 · Peach Springs, AZA quality control failure in the Sungear, Inc. manufacturing and quality control process allowed sungears with surface finishes of the root fillet radius of the spline that did not conform to the drawing specifications to be released. The surface finish…May 21, 2011 · N178GC · No damageNTSB ERA10TA493Accident · Minor injuriesFinal reportBell 412 · Brooklyn, NYThe fatigue fracture of the reduction gearbox output drive gear, which resulted in the loss of power output from the engines to the helicopter rotor blade system and a subsequent forced landing. The fracture of the output drive gear was caused by a fatigue…Sep 22, 2010 · N412PD · Substantial damageNTSB ERA09LA523Accident · No injuriesLimited investigationFinal reportCessna 208 · Sheffield, MAA total loss of engine power due to a failure of the 1st stage sun gear output splines for unknown reasons, which resulted in a power turbine overspeed condition, with subsequent blade distress/release.Sep 15, 2009 · N336DN · DestroyedNTSB CEN09LA602Accident · Minor injuriesLimited investigationFinal reportAir Tractor AT-301A · New Miner, WIA total loss of engine power due to the fatigue failure of the engine torsion shaft. Contributing to the accident was the chrome plating of the shaft by an undetermined maintenance/overhaul facility.Aug 22, 2009 · N3651R · 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\", '01057210'))
  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.