# NTSB investigations: Reduction gear and shaft

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 ERA23LA327](https://openairdocs.org/ntsb/ERA23LA327.md): Air Tractor AT502 · Leipsic, OH · Accident · No injuries · Class 3 · Limited · Final report · Aug 4, 2023 · N5048S · Substantial damage
  > The 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.
- [NTSB ENG23LA034](https://openairdocs.org/ntsb/ENG23LA034.md): Hall Lester R Legacy · Rochester, MN · Incident · No injuries · Class 3 · Limited · Final report · Jul 20, 2023 · N707MM · Minor damage
  > Mechanically 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…
- [NTSB DCA12IA114](https://openairdocs.org/ntsb/DCA12IA114.md): Boeing 787 · Charleston, SC · Incident · No injuries · Incident investigation · Final report · Jul 28, 2012 · VT-ANJ · Minor damage
  > The 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…
- [NTSB CEN11LA404](https://openairdocs.org/ntsb/CEN11LA404.md): Ayres S2R-T34 · Athleimer, AR · Accident · Minor injuries · Limited investigation · Final report · Jun 16, 2011 · N30902 · Substantial damage
  > Failure 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…
- [NTSB ENG11IA032](https://openairdocs.org/ntsb/ENG11IA032.md): Dehavilland DHC-6-300 · Peach Springs, AZ · Incident · No injuries · Incident investigation · Final report · May 21, 2011 · N178GC · No damage
  > A 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…
- [NTSB ERA10TA493](https://openairdocs.org/ntsb/ERA10TA493.md): Bell 412 · Brooklyn, NY · Accident · Minor injuries · Final report · Sep 22, 2010 · N412PD · Substantial damage
  > The 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…
- [NTSB ERA09LA523](https://openairdocs.org/ntsb/ERA09LA523.md): Cessna 208 · Sheffield, MA · Accident · No injuries · Limited investigation · Final report · Sep 15, 2009 · N336DN · Destroyed
  > A 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.
- [NTSB CEN09LA602](https://openairdocs.org/ntsb/CEN09LA602.md): Air Tractor AT-301A · New Miner, WI · Accident · Minor injuries · Limited investigation · Final report · Aug 22, 2009 · N3651R · Substantial damage
  > A 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.

## 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", '01057210'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-findings/01057210/cases

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.