# NTSB investigations: Tail rotor drive system

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 ERA25LA040](https://openairdocs.org/ntsb/ERA25LA040.md): Hughes 369D · Waycross, GA · Accident · Minor injuries · Class 4 · Limited · Final report · Nov 5, 2024 · N11AS · Substantial damage
  > An encounter with a foreign object, which resulted in a loss of control and collision with terrain.
- [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 ERA24LA263](https://openairdocs.org/ntsb/ERA24LA263.md): Rotorway Exec · Alva, FL · Accident · No injuries · Class 3 · Limited · Final report · Jun 14, 2024 · N99TE · Substantial damage
  > A loss of tail rotor control as a result of unsecured tail rotor drive belt tensioner bolts.
- [NTSB ERA24LA205](https://openairdocs.org/ntsb/ERA24LA205.md): Airbus Helicopters AS350B3 · Plant City, FL · Accident · No injuries · Class 3 · Limited · Final report · May 1, 2024 · N413JM · Substantial damage
  > The pilot’s inadequate yaw control of the helicopter while maneuvering at a low altitude and airspeed, which resulted in a hard landing.
- [NTSB ANC24LA013](https://openairdocs.org/ntsb/ANC24LA013.md): Robinson Helicopter R44 II · Glacier View, AK · Accident · No injuries · Class 3 · Limited · Final report · Feb 11, 2024 · N74868 · Substantial damage
  > A sudden stoppage of the tail rotor for unknown reasons, which resulted in the tortional overload failure of the tail rotor driveshaft.
- [NTSB WPR23LA004](https://openairdocs.org/ntsb/WPR23LA004.md): Bell 206B · Fresno, CA · Accident · Serious injuries · Class 3 · Limited · Final report · Oct 1, 2022 · N284CA · Substantial damage
  > The disbond of a tail rotor drive shaft splined adapter, which resulted in a loss of tail rotor drive and a subsequent hard landing.
- [NTSB WPR22LA340](https://openairdocs.org/ntsb/WPR22LA340.md): Bell Helicopter Textron 206L-1 · Banning, CA · Accident · Minor injuries · Class 3 · Limited · Final report · Sep 10, 2022 · N242BH · Substantial damage
  > The improper attachment of the tail rotor drive shaft to the air conditioner drive pulley without a drive ring, which resulted in the failure of the hardware, a loss of tail rotor drive, and the loss of control of the helicopter followed by a hard landing and…
- [NTSB WPR22LA084](https://openairdocs.org/ntsb/WPR22LA084.md): Bell UH-1E · Gustine, CA · Accident · No injuries · Class 3 · Limited · Final report · Jan 23, 2022 · N333XL · Substantial damage
  > Failure of the 90° gearbox due to the lack of lubricating oil, which resulted in a loss of rotational drive to the tail rotor and a subsequent loss of control of the helicopter.
- [NTSB ERA21LA386](https://openairdocs.org/ntsb/ERA21LA386.md): Hiller UH-12E · Millen, GA · Accident · Minor injuries · Class 3 · Limited · Final report · Sep 29, 2021 · N430NR · Substantial damage
  > The improper reassembly of the tail rotor gearbox following maintenance, which resulted in fatigue failure of the input pinion gear shaft, and the subsequent loss of tail rotor drive.
- [NTSB CEN21LA389](https://openairdocs.org/ntsb/CEN21LA389.md): Robinson Helicopter R22 Beta · Arnaudville, LA · Accident · Minor injuries · Class 3 · Limited · Final report · Aug 27, 2021 · N827SH · Substantial damage
  > The loss of tail rotor drive due to a fatigue failure of the tail rotor gearbox output shaft, which resulted in a loss of control during landing.
- [NTSB ERA21LA339](https://openairdocs.org/ntsb/ERA21LA339.md): Enstrom 280 · Port Orange, FL · Accident · No injuries · Class 3 · Limited · Final report · Aug 21, 2021 · N9285 · Substantial damage
  > The failure of the tail rotor drive shaft at the coupling due to torsionally applied shear stress.
- [NTSB ERA21FA195](https://openairdocs.org/ntsb/ERA21FA195.md): Bell Helicopter Textron Canada 429 · Eden, NC · Accident · 1 fatal · Class 3 · Field · Final report · Apr 28, 2021 · N53DE · Destroyed
  > The impact of the main rotor blades with the tail boom during low-altitude maneuvers, which severed the tail rotor drive shaft and resulted in a loss of control and impact with terrain.
- [NTSB ERA20LA310](https://openairdocs.org/ntsb/ERA20LA310.md): Robinson R22 · Fort Myers, FL · Accident · No injuries · Class 3 · Limited · Final report · Sep 6, 2020 · N194HC · Substantial damage
  > Foreign object damage of the turning tailrotor by a soft-bodied object, which resulted in the sudden stoppage of the tailrotor and the catastrophic failure of the tailrotor assembly and its mount structure.
- [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 CEN17LA375](https://openairdocs.org/ntsb/CEN17LA375.md): Hiller UH 12A · Griffith, IN · Accident · No injuries · Limited investigation · Final report · Sep 11, 2017 · N2686 · Substantial damage
  > The loss of tail rotor thrust due to a failed tail rotor driveshaft, which resulted in a loss of tail rotor control and a hard landing.
- [NTSB WPR17LA002](https://openairdocs.org/ntsb/WPR17LA002.md): Tamarack Helicopters UH-1H · Gila Bend, AZ · Accident · Minor injuries · Limited investigation · Final report · Oct 5, 2016 · N175SF · Substantial damage
  > The separation of the 90° tail rotor gearbox assembly as a result of fatigue to the tail rotor gearbox input quill assembly attachment studs due to the helicopter experiencing highly repetitive agricultural flight profiles for which it was not designed.
- [NTSB CEN16LA047](https://openairdocs.org/ntsb/CEN16LA047.md): Eurocopter EC120B · Goshen, IN · Accident · No injuries · Limited investigation · Final report · Nov 16, 2015 · N88HA · Substantial damage
  > The failure of the Thomas coupling at the interface with the main gear box tail rotor output shaft, which resulted in the helicopter's loss of tail rotor control.
- [NTSB CEN16LA027](https://openairdocs.org/ntsb/CEN16LA027.md): Bell 407 · San Antonio, TX · Accident · No injuries · Limited investigation · Final report · Nov 3, 2015 · N496AE · Substantial damage
  > The failure of the No. 3 tail rotor adapter and shaft due to a loss of torque on the retaining nut. Contributing to the accident was the lack of a requirement to inspect the tail rotor assembly for security in the helicopter manufacturer's maintenance manual…
- [NTSB ERA16LA015](https://openairdocs.org/ntsb/ERA16LA015.md): Bell 206L 3 · Dickinson, AL · Accident · No injuries · Limited investigation · Final report · Oct 15, 2015 · N206CJ · Substantial damage
  > The improper installation by company maintenance personnel of the securing hardware of a tail rotor driveshaft section, which resulted in that section of tail rotor driveshaft disconnecting and a complete loss of tail rotor thrust.
- [NTSB ANC15LA073](https://openairdocs.org/ntsb/ANC15LA073.md): Robinson Helicopter R44 · Fort Glenn, AK · Accident · No injuries · Limited investigation · Final report · Sep 19, 2015 · N7162R · Substantial damage
  > The separation of the tail rotor gearbox from the tailboom attachment point due to overstress loads imposed by a tail rotor blade imbalance as the result of impact with an undetermined object during low-level flight operations.
- [NTSB CEN15LA412](https://openairdocs.org/ntsb/CEN15LA412.md): Guisinger Gary G Baby Belle · Stuart, IA · Accident · Minor injuries · Limited investigation · Final report · Sep 12, 2015 · N135PA · Substantial damage
  > The failure of the tail rotor driveshaft for reasons that could not be determined due to the mechanically and thermally deformed fracture surface.
- [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 ERA15LA218](https://openairdocs.org/ntsb/ERA15LA218.md): Bell 206L-3 · Kearny, NJ · Accident · No injuries · Limited investigation · Final report · May 20, 2015 · N210MH · Substantial damage
  > The deliberate concealment and reuse of an unairworthy tail rotor driveshaft by unknown personnel, which resulted in an overstress separation at a bonded flange adapter as a result of driveshaft imbalance.
- [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 ERA13LA390](https://openairdocs.org/ntsb/ERA13LA390.md): Continental Copters 47G · Sandy Hook, KY · Accident · No injuries · Limited investigation · Final report · Aug 31, 2013 · N6356X · Substantial damage
  > The in-flight disengagement of the tail rotor extension shaft from the tail rotor gearbox, resulting in a loss of tail rotor control.
- [NTSB ANC13TA076](https://openairdocs.org/ntsb/ANC13TA076.md): Bell UH-1B · Tok, AK · Accident · No injuries · Final report · Aug 8, 2013 · N70NW · Substantial damage
  > The failure of the tail rotor crosshead bearing, which resulted in a loss of tail rotor control.
- [NTSB CEN13FA192](https://openairdocs.org/ntsb/CEN13FA192.md): Sikorsky S-76A++ · Grand Lake, LA · Accident · 3 fatal · Field investigation · Final report · Mar 15, 2013 · N574EH · Destroyed
  > Fracture of the red tail rotor blade spar, which resulted in the separation and departure of the red tail rotor blade from the helicopter and subsequent compromised tail gearbox. The red tail rotor blade was not recovered, thus the cause of the initial…
- [NTSB ANC13FA017](https://openairdocs.org/ntsb/ANC13FA017.md): Eurocopter AS350 B3 · Beluga, AK · Accident · Serious injuries · Field investigation · Final report · Dec 15, 2012 · C-GYPH · Substantial damage
  > The pilot's failure to stabilize the external load, which led to the synthetic long-line separating about midspan and the remaining line becoming entangled in the tail rotor gearbox output shaft and resulted in the separation of the tail rotor gearbox and…
- [NTSB WPR13FA006](https://openairdocs.org/ntsb/WPR13FA006.md): Garlick Helicopters UH-1H · Shady Cove, OR · Accident · Minor injuries · Field investigation · Final report · Oct 7, 2012 · N1577 · Substantial damage
  > The separation of the tail rotor gearbox and tail rotor assembly as a result of fatigue to the tail rotor gearbox input quill assembly attachment studs.
- [NTSB ANC12CA100](https://openairdocs.org/ntsb/ANC12CA100.md): Aerospatiale AS350 B2 · Talkeetna, AK · Accident · No injuries · Data collection · Final report · Sep 1, 2012 · N178CH · Substantial damage
  > The entanglement of a plastic tarp in the helicopter’s tail rotor after becoming dislodged from its securement.
- [NTSB CEN12LA525](https://openairdocs.org/ntsb/CEN12LA525.md): Bell 214ST · Avalon, TX · Accident · No injuries · Limited investigation · Final report · Aug 7, 2012 · N409SB · Substantial damage
  > Maintenance personnel’s failure to properly torque the retaining nut and install the cotter pin that secured the helicopter’s tail rotor counterweight bellcrank. Contributing to the accident was the lack of detailed maintenance records that documented…
- [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 CEN12LA120](https://openairdocs.org/ntsb/CEN12LA120.md): Continental Copters 47G2 · Lohn, TX · Accident · Serious injuries · Limited investigation · Final report · Jan 1, 2012 · N9021R · Substantial damage
  > The improper installation of the tail rotor gearbox by maintenance personnel, which led to accelerated wear of the ring and pinion gears, resulting in the loss of tail rotor effectiveness and subsequent forced landing.
- [NTSB WPR11LA282](https://openairdocs.org/ntsb/WPR11LA282.md): Hiller UH12E · Hanford, CA · Accident · No injuries · Limited investigation · Final report · Jun 23, 2011 · N99579 · Substantial damage
  > The separation of the tail rotor drive gear shaft due to torsional fatigue of its threaded portion, which resulted in a loss of tail rotor control.
- [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 CEN11LA315](https://openairdocs.org/ntsb/CEN11LA315.md): Hughes 269B · Edgerton, IN · Accident · No injuries · Limited investigation · Final report · Apr 29, 2011 · N9561F · Substantial damage
  > A loss of clearance between the tail rotor drive shaft and the tailboom bulkhead for undetermined reasons, which resulted in the overstress failure of the drive shaft.
- [NTSB CEN11IA156](https://openairdocs.org/ntsb/CEN11IA156.md): Sikorsky 92 · Galliano, LA · Incident · No injuries · Incident investigation · Final report · Jan 19, 2011 · N920AL · Minor damage
  > The misalignment of the retaining washer during routine maintenance, resulting in the subsequent separation of the washer and nut.
- [NTSB WPR09LA226](https://openairdocs.org/ntsb/WPR09LA226.md): MD Helicopter 369FF · Santa Clarita, CA · Accident · No injuries · Limited investigation · Final report · May 1, 2009 · N67FF · Substantial damage
  > The pilot's failure to maintain clearance from the water while maneuvering at low altitude as a result of the helicopter's grappling hook temporarily becoming ensnared with an underwater obstruction.
- [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.
- [NTSB LAX08LA183](https://openairdocs.org/ntsb/LAX08LA183.md): Robinson R44 II · Topanga, CA · Accident · Minor injuries · Limited investigation · Final report · Jun 15, 2008 · N168AG · Substantial damage
  > The in-flight separation of the tail rotor gear box for an undetermined reason. Contributing to the accident was the hilly terrain, which was unsuitable for a forced landing.
- [NTSB CHI08LA104](https://openairdocs.org/ntsb/CHI08LA104.md): Vic Tatelman Baby Belle · Lakeland, FL · Accident · No injuries · Limited investigation · Final report · Apr 9, 2008 · N6261N · Substantial damage
  > The failure of the tailrotor driveshaft hanger bearing and jamming of the tailrotor.
- [NTSB DFW08LA100](https://openairdocs.org/ntsb/DFW08LA100.md): Hiller UH-12E · Quinton, OK · Accident · No injuries · Limited investigation · Final report · Apr 7, 2008 · N34SD · Substantial damage
  > An undetermined mechanical malfuction associated with the tail rotor drive system which led to a loss of control.
- [NTSB NYC08FA134](https://openairdocs.org/ntsb/NYC08FA134.md): Robinson R22 Beta II · Wilmington, NC · Accident · 1 fatal · Field investigation · Final report · Mar 13, 2008 · N2215R · Substantial damage
  > The pilot's failure to maintain proper rotor rpm after a partial loss of engine power.

## 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", '010465'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-findings/010465/cases

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