# NTSB investigations: Allison 250-C20 series: Loss of engine power (partial)

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 WPR26LA347](https://openairdocs.org/ntsb/WPR26LA347.md): Bell 206B-III · Creswell, NC · Accident · No injuries · Class 3 · Limited · Preliminary report · Sep 18, 2026 · N50141 · Substantial damage
  > On September 18, 2026, at 1018 eastern daylight time, a Bell 206B-III, N50141, was substantially damaged when it was involved in an accident near Creswell, North Carolina. The pilot was not injured. The helicopter was being operated as a Title 14 Code of…
- [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 CEN22LA146](https://openairdocs.org/ntsb/CEN22LA146.md): Hughes 369 · Adair, IA · Accident · Minor injuries · Class 3 · Limited · Final report · Mar 17, 2022 · N500MZ · Substantial damage
  > The mechanic’s failure to properly torque a fuel control unit B-nut, which resulted in a partial loss of engine power, an attempted autorotation, and an impact with terrain.
- [NTSB ERA22LA117](https://openairdocs.org/ntsb/ERA22LA117.md): Hughes 369D · Bel Air, MD · Accident · No injuries · Class 3 · Limited · Final report · Feb 9, 2022 · N9159F · Substantial damage
  > A loss of engine power due to bearing failures in the turbine section resulting from a fatigue fracture of the oil supply line that fed oil to the Nos. 6 and 7 bearings. The oil line failure led to rapid deterioration of the bearings from oil starvation.…
- [NTSB WPR19LA087](https://openairdocs.org/ntsb/WPR19LA087.md): MD Helicopter 369 · Kukuihaele, HI · Accident · Serious injuries · Class 3 · Limited · Final report · Feb 21, 2019 · N506PH · Substantial damage
  > The partial loss of engine power due to corrosion in the engine bleed valve due to wash solution intrusion. Contributing to the accident was the installation of a bushing manufactured to incorrect dimensions in the bleed valve, and the uneven terrain at the…
- [NTSB WPR18LA164](https://openairdocs.org/ntsb/WPR18LA164.md): Bell 206 · Sanders, KY · Accident · Minor injuries · Class 3 · Limited · Final report · Jun 5, 2018 · N518Z · Substantial damage
  > A partial loss of engine power for undetermined reasons, and a loss of main rotor rpm during the subsequent autorotation, which resulted in a hard landing.
- [NTSB CEN14IA270](https://openairdocs.org/ntsb/CEN14IA270.md): Bell 407 · Eugene Island 182A · Incident · No injuries · Incident investigation · Final report · May 30, 2014 · N1197 · No damage
  > The improper repair of the outer combustion case, which led to its ultimate failure due to the continued progression of a fatigue crack and resulted in a partial loss of engine power during takeoff.
- [NTSB WPR12LA125](https://openairdocs.org/ntsb/WPR12LA125.md): Aerospatiale AS 355F1 · Makakilo City, HI · Accident · No injuries · Limited investigation · Final report · Mar 3, 2012 · N101MZ · Substantial damage
  > A partial loss of engine power while maneuvering over rough/uneven terrain that was precipitated by the failure of a 3rd stage turbine blade as a result of high-cycle fatigue.

## 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.engine_model_code IN ('03020')
    AND EXISTS (SELECT 1 FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' e WHERE e.case_mkey = x.case_mkey AND e.aircrafts_position = x.position AND e."isDefiningEvent" AND e."tier2Number" = '342'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-events/342/cases?engine=03020

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