# NTSB investigations: Tail rotor drive system, general

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 ANC24LA077](https://openairdocs.org/ntsb/ANC24LA077.md): Robinson R44 · Honolulu, HI · Accident · No injuries · Class 3 · Limited · Final report · Aug 19, 2024 · N740RH · Substantial damage
  > A 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.
- [NTSB CEN19LA174](https://openairdocs.org/ntsb/CEN19LA174.md): Robinson R44 · Key West, FL · Accident · No injuries · Class 3 · Limited · Final report · Jun 17, 2019 · N1241W · Substantial damage
  > The 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.
- [NTSB CEN19LA065](https://openairdocs.org/ntsb/CEN19LA065.md): Robinson R44 · Uvalde, TX · Accident · Minor injuries · Limited investigation · Final report · Jan 8, 2019 · N484AB · Substantial damage
  > The 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.
- [NTSB CEN18LA247](https://openairdocs.org/ntsb/CEN18LA247.md): Safari 400 · Aguilares, TX · Accident · Serious injuries · Limited investigation · Final report · Jul 2, 2018 · N326RW · Substantial damage
  > The loss of tail rotor control due to the in-flight failure of the tail rotor pinion.
- [NTSB CEN15LA379](https://openairdocs.org/ntsb/CEN15LA379.md): Robinson Helicopter R44 II · Ketchum, OK · Accident · Minor injuries · Limited investigation · Final report · Aug 25, 2015 · N444KD · Substantial damage
  > The 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.
- [NTSB WPR14LA225](https://openairdocs.org/ntsb/WPR14LA225.md): Emery Mark Rotorway 162F · Merced, CA · Accident · No injuries · Limited investigation · Final report · Jun 4, 2014 · N78291 · Destroyed
  > The 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…
- [NTSB ERA12LA368](https://openairdocs.org/ntsb/ERA12LA368.md): Schweizer 269C · Piney Flats, TN · Accident · No injuries · Limited investigation · Final report · May 24, 2012 · N760DA · Substantial damage
  > The 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.
- [NTSB CEN12LA181](https://openairdocs.org/ntsb/CEN12LA181.md): Sikorsky 269C · Staples, TX · Accident · No injuries · Limited investigation · Final report · Mar 5, 2012 · N1099N · Substantial damage
  > The 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.
- [NTSB CEN11LA414](https://openairdocs.org/ntsb/CEN11LA414.md): Enstrom F-28C-2 · Blair, NE · Accident · No injuries · Limited investigation · Final report · Jun 23, 2011 · N5694A · Substantial damage
  > The 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.
- [NTSB NYC08CA252](https://openairdocs.org/ntsb/NYC08CA252.md): Buschmann Robert E Helicycle · Stuart, FL · Accident · Minor injuries · Data collection · Final report · Jul 19, 2008 · N3375C · Substantial damage
  > The pilot's improper decision to take off with a known discrepancy. Contributing to the accident was spilled fuel on the drive belts.

## 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", '01046500'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-findings/01046500/cases

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