# NTSB investigations: Hiller UH-12E: Airframe/component/system failure/malfunction

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 SEA00TA013](https://openairdocs.org/ntsb/SEA00TA013.md): Hiller UH-12E · Stites, ID · Accident · Serious injuries · Final report · Nov 2, 1999 · N5388V · Substantial damage
  > Inadequate inspection of the control rotor cuff by a company mechanic and subsequent fatigue fracture of the cuff, resulting in an inflight separation of the control rotor blade. Factors contributing to the accident were: inadequate quality control during…
- [NTSB SEA99FA013](https://openairdocs.org/ntsb/SEA99FA013.md): Hiller UH-12E · Marshall, WA · Accident · 1 fatal · Field investigation · Final report · Nov 10, 1998 · N752GB · Destroyed
  > The loss of the bolt that connects the lateral cyclic linkage push rod to the lower end of the upper firewall-mounted lateral cyclic linkage bellcrank, resulting in an uncontrolled descent into the terrain.
- [NTSB FTW98LA253](https://openairdocs.org/ntsb/FTW98LA253.md): Hiller UH-12E · Delaplaine, AR · Accident · No injuries · Limited investigation · Final report · Jun 2, 1998 · N4028T · Substantial damage
  > The failure of maintenance personnel to comply with and airworthiness directive, which resulted in failure of the planetary gear due to lack of lubrication. A contributing factors was the lack of suitable terrain for the pilot to execute a forced landing.
- [NTSB NYC97LA101](https://openairdocs.org/ntsb/NYC97LA101.md): Hiller UH-12E · Granby, NY · Accident · Serious injuries · Limited investigation · Final report · May 29, 1997 · N4029S · Substantial damage
  > failure of the pilot/owner to replace the torsional clutch as specified by the manufacturer, and subsequent failure of the helicopter's clutch, which resulted in a forced landing (autorotation). A related factor was: the encounter with trees in the emergency…
- [NTSB FTW96LA385](https://openairdocs.org/ntsb/FTW96LA385.md): Hiller UH12E · Hamburg, AR · Accident · Minor injuries · Limited investigation · Final report · Sep 12, 1996 · N156HA · Substantial damage
  > The loss of tail rotor control as result of a tail rotor blade strike by a partially disconnected ballast weight, due to a disconnected pin. A factor was the lack of suitable terrain for the forced landing.
- [NTSB LAX96LA279](https://openairdocs.org/ntsb/LAX96LA279.md): Hiller UH-12E · Healdsburg, CA · Accident · No injuries · Limited investigation · Final report · Jul 20, 1996 · N124HA · Substantial damage
  > The failure of the pilot to confirm a loss of power before entering autorotation after reading an erroneous instrument indication on the helicopter's dual tachometer. Factors in the accident were the erratic instrument, and maintenance personnel who failed to…
- [NTSB ATL96LA104](https://openairdocs.org/ntsb/ATL96LA104.md): Hiller UH-12E · Cottondale, FL · Accident · No injuries · Limited investigation · Final report · Jul 11, 1996 · N102HT · Substantial damage
  > failure of the main rotor drive torsional coupling and inner gimbal ring, which resulted in jamming of the flight controls during an attempted autorotation.
- [NTSB LAX95LA318](https://openairdocs.org/ntsb/LAX95LA318.md): Hiller UH-12E · Dos Palos, CA · Accident · No injuries · Limited investigation · Final report · Sep 1, 1995 · N4027D · Substantial damage
  > the fatigue failure of the tail rotor tension torsion bar plates.
- [NTSB LAX95LA109](https://openairdocs.org/ntsb/LAX95LA109.md): Hiller UH-12E · Arvin, CA · Accident · No injuries · Limited investigation · Final report · Feb 15, 1995 · N5335V · Substantial damage
  > The seizure of the transmission due to lack of lubrication from a plugged oil supply line.
- [NTSB LAX95LA096](https://openairdocs.org/ntsb/LAX95LA096.md): Hiller UH-12E · Chowchilla, CA · Accident · No injuries · Limited investigation · Final report · Feb 3, 1995 · N9293Z · Destroyed
  > the in-flight failure and separation of the main rotor hub due to a fatigue crack.
- [NTSB SEA94LA149](https://openairdocs.org/ntsb/SEA94LA149.md): Hiller-Soloy UH-12L4 · Clarkston, WA · Accident · Minor injuries · Limited investigation · Final report · Jun 14, 1994 · N67264 · Substantial damage
  > Disconnection of the ballast bar aft retaining pin. Factor(s) were: tail rotor blade separation and reduced aircraft control.
- [NTSB LAX94LA054](https://openairdocs.org/ntsb/LAX94LA054.md): Hiller UH-12E · Salinas, CA · Accident · Minor injuries · Limited investigation · Final report · Nov 20, 1993 · N161HA · Substantial damage
  > a fatigue failure of the torsion-tension bar pin due to fretting corrosion. A factor in this accident was an inadequate quality of material utilized in the manufacture of the pin.
- [NTSB LAX94LA043](https://openairdocs.org/ntsb/LAX94LA043.md): Hiller UH-12E · Salinas, CA · Accident · No injuries · Limited investigation · Final report · Nov 13, 1993 · N149HA · Destroyed
  > The pilot's improper handling of the helicopter which resulted in overloading of the rotor system in a maneuvering turn during aerial application of chemical, and subsequent failure of the main rotor paddle assembly.
- [NTSB LAX92LA349](https://openairdocs.org/ntsb/LAX92LA349.md): Hiller UH12-E, Saloy Conver · Arvin, CA · Accident · Minor injuries · Limited investigation · Final report · Aug 15, 1992 · N9753C · Substantial damage
  > The failure of the tension torsion bar pin due to fatigue. Contributing to this accident was that it was not possible for the pilot to flare the helicopter on landing.
- [NTSB LAX92LA146](https://openairdocs.org/ntsb/LAX92LA146.md): Hiller UH-12E · Huron, CA · Accident · No injuries · Limited investigation · Final report · Mar 21, 1992 · N93478 · Destroyed
  > A separation of the control rotor cuff due to fatigue.
- [NTSB LAX91LA191](https://openairdocs.org/ntsb/LAX91LA191.md): Hiller UH-12E · Delano, CA · Accident · No injuries · Limited investigation · Final report · May 4, 1991 · N4414 · Substantial damage
  > That the pilot improperly performed the autorotation by misjudging the flare altitude. Contributing to this accident was the total failure of the freewheeling sprag clutch due to excessive wear and the soft dirt terrain.
- [NTSB CHI90DTG02](https://openairdocs.org/ntsb/CHI90DTG02.md): Hiller UH-12-E · Garrison, ND · Accident · No injuries · Final report · Aug 4, 1990 · N133HA · Substantial damage
  > The failure of the helicopter tail rotor control cable. A factor related to the accident was the chafing of the tail rotor control cable.
- [NTSB CHI89DEM09](https://openairdocs.org/ntsb/CHI89DEM09.md): Hiller UH-12E · Hudsonville, MI · Accident · Minor injuries · Final report · Sep 28, 1989 · N4028T · Substantial damage
  > The fatigue failure of one of the tension-torsion pins.
- [NTSB CHI89DEP04](https://openairdocs.org/ntsb/CHI89DEP04.md): Hiller UH-12E · Waterford, WI · Accident · No injuries · Final report · May 22, 1989 · N3829 · Substantial damage
  > The pilot's inability to maintain control during an autorotational landing attempt following the failure of the main rotor drive train torsional coupling.
- [NTSB LAX89DVM02](https://openairdocs.org/ntsb/LAX89DVM02.md): Hiller UH-12E · Salinas, CA · Accident · Minor injuries · Final report · Apr 26, 1989 · N169HA · Substantial damage
  > The separation of the torsion coupling in the main rotor drive system.
- [NTSB CHI88DER06](https://openairdocs.org/ntsb/CHI88DER06.md): Hiller UH-12E · Buffalo Lake, MN · Accident · No injuries · Final report · Jul 30, 1988 · N173HA · Destroyed
  > When the helicopter lifted off, the left tail rotor cable separated. Directional control was lost and the aircraft collided with the terrain. The pilot reported no injuries, however the helicopter sustained substantial damage. An inspection of the left tail…
- [NTSB LAX87DUJ11](https://openairdocs.org/ntsb/LAX87DUJ11.md): Hiller UH-12E · Scottsdale, AZ · Accident · Minor injuries · Final report · Sep 1, 1987 · N236HA · Destroyed
  > During an aerial application flight, the plt made a turn-around & was starting to make another swath run when he heard a loud 'bang' & then the helicopter collided with terrain. An inspn of the main rotor head & pin revealed the hub had failed from hi cycle…
- [NTSB LAX86FVA14](https://openairdocs.org/ntsb/LAX86FVA14.md): Hiller UH-12E · Lemoore, CA · Accident · Minor injuries · Final report · Sep 18, 1986 · N688SB · Substantial damage
  > The plt reptd that while returning to the loading area after spraying a field, he heard a loud pop emanating from the engine compartment. Shortly thereafter he observed a fire in the engine compartment and lost forward and aft control of the helicopter. The…
- [NTSB LAX86DVA09](https://openairdocs.org/ntsb/LAX86DVA09.md): Hiller UH-12E · Delano, CA · Accident · No injuries · Final report · Jun 17, 1986 · N172ET · Substantial damage
  > The helicopter rotor blade delaminated shortly after departing the operator's north base at Delano, CA. The investigation determined the blade contained extensive voids on the bond line. The blade was rejected by the manufacturer as being unairworthy. The…
- [NTSB LAX86FVM05](https://openairdocs.org/ntsb/LAX86FVM05.md): Hiller UH12E · Castroville, CA · Accident · Minor injuries · Final report · Apr 27, 1986 · N5374V · Destroyed
  > The acft landed hard and rolled over after the lndg skid failed in a forced lndg. The plt said he was crusing at 500 ft AGL over an open field when he heard a loud bang. The helicopter began to vibrate severely and spiral to the right. The plt lost ground…
- [NTSB SEA86FA039](https://openairdocs.org/ntsb/SEA86FA039.md): Hiller-Soloy UH-12E · Horton, OR · Accident · 1 fatal · Field investigation · Final report · Jan 16, 1986 · N40290 · Destroyed
  > The fork connecting the rotorcraft's blue blade to the main rotor hub separated after a long term fatigue crack had spread through more than 60% of the fork circumference. The operator failed to carry out the appropriate inspection of the fork unit as…
- [NTSB DEN86LA016](https://openairdocs.org/ntsb/DEN86LA016.md): Hiller UH-12E · Vernal, UT · Accident · No injuries · Limited investigation · Final report · Nov 1, 1985 · N400AH · Substantial damage
  > The plt stated he had just departed a site located on top of a mountain, which is approximately 12,200 ft MSL. The pilot said 30 seconds later, the helicopter lost partial power. Requiring him to make a force landing. The inspection of the turbocharger…
- [NTSB LAX84LA494](https://openairdocs.org/ntsb/LAX84LA494.md): Hiller UH12ET · Yuma, AZ · Accident · Serious injuries · Limited investigation · Final report · Sep 25, 1984 · N9278Z · Destroyed
  > The pilot stated that he was carrying a load of pesticide for application on a broccoli field. The aircraft was in level flight, approximately 4 to 8 feet AGL when it became uncontrollable and impacted the ground. The aircraft was consumed by a post crash…
- [NTSB SEA84LA174](https://openairdocs.org/ntsb/SEA84LA174.md): Hiller UH-12E · Redmond, OR · Accident · Minor injuries · Limited investigation · Final report · Jul 16, 1984 · N1043L · Substantial damage
  > The acft collided with the ground after a in-flt main rotor blade separation during an aerial application flt. Inspection of the fracture surface of the failed blade revealed characteristics consistant with the high stress, low cycle fatigue. Lab findings…
- [NTSB ATL83LA355](https://openairdocs.org/ntsb/ATL83LA355.md): Hiller UH-12E · Cameron, SC · Accident · No injuries · Limited investigation · Final report · Sep 5, 1983 · N4029R · Substantial damage
  > The plt stated that he was on a trimming/swath run at about 15 ft AGL & 15 mph when he heard a strange noise which was followed by a 180 deg yaw. Subsequently, the helicopter crash landed, damaging the tail boom & tail rotor blades and spreading the landing…
- [NTSB MKC83LA207](https://openairdocs.org/ntsb/MKC83LA207.md): Hiller UH-12E · Corwith, IA · Accident · Minor injuries · Limited investigation · Final report · Aug 31, 1983 · N173HA · Destroyed
  > While en route, the plt heard a clanking noise behind him which was followed by a severe vibration of the flt controls. He initiated an autorotative descent from 3000 ft. he said the helicopter began to roll left, then righted itself. The helicopter touched…
- [NTSB CHI83LA297](https://openairdocs.org/ntsb/CHI83LA297.md): Hiller UH-12E · Brooten, MN · Accident · No injuries · Limited investigation · Final report · Jul 5, 1983 · N4028K · Substantial damage
  > The helicopter had just lifted off of the flatbed of a truck when it started to spin. The plt lowered the collective, reduced the power & landed beside the truck. During touchdown, the main rotor blades struck the truck. An investigation revealed that the…

## 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 x.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' x WHERE x.aircraft_model_code IN ('4360122', '4360137')
    AND EXISTS (SELECT 1 FROM 'https://openairdocs.org/data/latest/ntsb_occurrences.parquet' o WHERE o.case_mkey = x.case_mkey AND o.aircrafts_position = x.position AND o."occurrenceNumber" = 1 AND o."occurrenceCode" = 130))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb?model=4360122&occurrence=130

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