# Main rotor gearbox

- Type: NTSB finding subsection
- Path: [Aircraft](https://openairdocs.org/ntsb-findings/01) › [Aircraft propeller/rotor](https://openairdocs.org/ntsb-findings/0104) › [Main rotor drive](https://openairdocs.org/ntsb-findings/010463) › Main rotor gearbox
- NTSB code: 01046320
- Cases: 2
- In the probable cause: 2
- Fatal cases: 0
- All cases: https://openairdocs.org/ntsb-findings/01046320/cases.md
- Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/01046320/cases.md?cause=1
- Page: https://openairdocs.org/ntsb-findings/01046320

## Cases per year (in the probable cause / all)

- 2008: 1 / 1
- 2018: 1 / 1

## Defining events in these cases

- [Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333): 1 cases
- [Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330): 1 cases

## Aircraft models (registry)

- [Eurocopter France SA330J](https://openairdocs.org/model/eurocopter-france-sa330j): 1 cases
- [Schultz George E MINI 500](https://openairdocs.org/model/schultz-george-e-mini-500): 1 cases

## Other findings in the same cases

- [Aircraft control](https://openairdocs.org/ntsb-findings/02063040) (Personnel issues): 1 cases
- [Scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010) (Personnel issues): 1 cases

## Newest cases

- [NTSB ANC18LA020](https://openairdocs.org/ntsb/ANC18LA020), Jan 26, 2018: Eurocopter France SA330J Puma (N339EV), Pacific Ocean, Japan, substantial damage. Probable cause: The worn rear bearing of the freewheel unit. Contributing to the accident was the delay in analyzing an oil sample, which would have detected the increase in metal contaminants from the worn bearing.
- [NTSB CHI08CA105](https://openairdocs.org/ntsb/CHI08CA105), Apr 6, 2008: Schultz Mini 500 (N62GS), Batavia, OH, substantial damage. Probable cause: The failure of the helicopter's centrifugal clutch during hover which led to the pilot's inability to maintain control of the craft and its subsequent impact with the ground.

NTSB has coded findings and defining events since 2008; earlier cases used its older occurrence and cause codes and aren't counted.

Findings: https://openairdocs.org/ntsb-findings.md. Defining events: https://openairdocs.org/ntsb-events.md. Phases of flight: https://openairdocs.org/ntsb-phases.md. Every investigation, filtered by finding, event, phase, state, year or model: https://openairdocs.org/ntsb.md (for example ?state=MI&fatal=1).

NTSB's definitions: Accident and incident, 49 CFR 830.2 (https://www.ecfr.gov/current/title-49/subtitle-B/chapter-VIII/part-830/subpart-A/section-830.2), CICTT occurrence categories (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/OccurrenceCategoryDefinitions.pdf), CICTT phases of flight (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/PhaseofFlightDefinitions.pdf), and NTSB coding manual, before 2008 (PDF) (https://www.ntsb.gov/GILS/Documents/codman.pdf). NTSB publishes no definitions for its findings, only their names.

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