# NTSB investigations: Allison 250-C20 series, UT

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 WPR26LA199](https://openairdocs.org/ntsb/WPR26LA199.md): Bell 206-L4 · Cedar City, UT · Accident · Minor injuries · Class 4 · Limited · Final report · May 23, 2026 · N917SU · Substantial damage
  > The flight instructor's failure to maintain helicopter control while manipulating the engine governor reference rpm adjustment during hover operations, which resulted in a loss of control and impact with the ground.
- [NTSB WPR23LA278](https://openairdocs.org/ntsb/WPR23LA278.md): Aerospatiale AS-355E Twin Star · Farmington, UT · Accident · No injuries · Class 3 · Limited · Final report · Jul 19, 2023 · N102UM · Substantial damage
  > The premature failure of one of the No. 2 engine compressor bleed valve, which resulted in a partial loss of power to that engine.
- [NTSB WPR14LA113](https://openairdocs.org/ntsb/WPR14LA113.md): Bell 206 · Bountiful, UT · Accident · No injuries · Limited investigation · Final report · Feb 5, 2014 · N3211N · Substantial damage
  > The pilots' inaccurate assessment of the snow depth on the landing zone, which resulted in a landing on snow deeper than that for which the helicopter was equipped and led to dynamic rollover.
- [NTSB WPR11LA151](https://openairdocs.org/ntsb/WPR11LA151.md): Bell 206B-III · Tooele, UT · Accident · No injuries · Limited investigation · Final report · Mar 1, 2011 · N206BY · Substantial damage
  > The pilot did not maintain yaw control of the helicopter during a maneuvering hover. Contributing to the accident was the pilot’s lack of experience in the make and model helicopter.
- [NTSB SEA06LA135](https://openairdocs.org/ntsb/SEA06LA135.md): Hughes 369D · Moab, UT · Accident · No injuries · Limited investigation · Final report · Jun 30, 2006 · N369PB · Substantial damage
  > The failure of the collective bungee support bracket due to non-compliance with a service information notice, which resulted in the pilot executing a precautionary autorotative landing. A contributing factor was the lack of suitable terrain for the landing.
- [NTSB DEN05LA024](https://openairdocs.org/ntsb/DEN05LA024.md): Bell 206B3 · Eureka, UT · Accident · No injuries · Limited investigation · Final report · Nov 13, 2004 · N130JH · Substantial damage
  > the pilot's improper in-flight planning and decision making and failure to maintain obstacle clearance, resulting in contact with a power transmission line. Contributing factors include the intentional low-level maneuver, the power transmission line, and the…
- [NTSB DEN02LA046](https://openairdocs.org/ntsb/DEN02LA046.md): Bell 206B-III · Moab, UT · Accident · No injuries · Limited investigation · Final report · May 24, 2002 · N191RH · Substantial damage
  > The pilot's failure to maintain rotor rpm during a forced landing. A contributing factor was fuel starvation.
- [NTSB FTW02LA102](https://openairdocs.org/ntsb/FTW02LA102.md): Bell 206L-3 · Oakley, UT · Accident · No injuries · Limited investigation · Final report · Mar 26, 2002 · N30YB · Substantial damage
  > The loss of engine power for an undetermined reason. A contributing factor was the lack of suitable terrain for the forced landing.
- [NTSB DEN02GA016](https://openairdocs.org/ntsb/DEN02GA016.md): Hughes 369E · Park City, UT · Accident · 3 fatal · Final report · Dec 27, 2001 · N280SP · Destroyed
  > the pilot's inadequate visual lookout, resulting in an inflight collision with powerlines. Contributing factors were the fog and the powerlines.
- [NTSB DEN02LA013](https://openairdocs.org/ntsb/DEN02LA013.md): Bell 206B · Bryce, UT · Accident · Serious injuries · Limited investigation · Final report · Dec 1, 2001 · N911KH · Substantial damage
  > loss of engine power for reasons undetermined. Contributing factors were the low airspeed and altitude at which to perform an autorotation.
- [NTSB DEN99TA031](https://openairdocs.org/ntsb/DEN99TA031.md): Hughes 369D · Woodruff, UT · Accident · No injuries · Final report · Jan 4, 1999 · N5013P · Substantial damage
  > A partial loss of engine power due to erosion in the compressor assembly module. Factors were a missing rotating labyrinth seal, the installation of which had not been performed by unknown maintenance personnel.
- [NTSB SEA92FA016](https://openairdocs.org/ntsb/SEA92FA016.md): Bell 206B · Salt Lake City, UT · Accident · 1 fatal · Field investigation · Final report · Nov 8, 1991 · N5736B · Destroyed
  > The pilot failed to maintain directional control. Factors to the accident were: inadeqaute remedial action, over confidence in personal ability, and lack of recent expereince.
- [NTSB SEA91TL#02](https://openairdocs.org/ntsb/SEA91TL%2302.md): Hiller-Soloy UH-12E · Vernal, UT · Accident · No injuries · Class 3 · Final report · Sep 18, 1991 · N7173S · Destroyed

## 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."eventStateOrRegion" = 'UT' AND c."eventCountry" = 'USA'
  AND c."mKey" IN (SELECT x.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' x WHERE x.engine_model_code IN ('03020'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb?engine=03020&state=UT

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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.