# NTSB investigations: Allison 250-C20 series: Loss of control in flight

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 WPR20CA162](https://openairdocs.org/ntsb/WPR20CA162.md): Bell 206 · Elko, NV · Accident · No injuries · Class 4 · Data collection · Final report · May 30, 2020 · N401HP · Substantial damage
  > The pilot's failure to maintain helicopter control in gusting wind that resulted in a loss in altitude and subsequent collision with a fence.
- [NTSB GAA18CA512](https://openairdocs.org/ntsb/GAA18CA512.md): Bell 206 · Battle Mountain, NV · Accident · No injuries · Class 4 · Data collection · Final report · Aug 18, 2018 · N8052G · Destroyed
  > The pilot's failure to maintain the proper altitude and airspeed while flying in a canyon in gusting wind conditions.
- [NTSB GAA18CA117](https://openairdocs.org/ntsb/GAA18CA117.md): Hughes Helicopters 369 · Wrightwood, CA · Accident · No injuries · Data collection · Final report · Feb 1, 2018 · N618SG · Substantial damage
  > The pilot’s high altitude, high gross weight landing with insufficient tail rotor thrust resulting in a loss of tail rotor effectiveness.
- [NTSB WPR18FA074](https://openairdocs.org/ntsb/WPR18FA074.md): Hughes 369D · Pomeroy, WA · Accident · 1 fatal · Field investigation · Final report · Jan 27, 2018 · N369TH · Substantial damage
  > A loss of control following the gunner's failure to ensure that the net maintained clearance from the tail rotor.
- [NTSB CEN14CA525](https://openairdocs.org/ntsb/CEN14CA525.md): Bell 206B · Nashoba, OK · Accident · No injuries · Data collection · Final report · Sep 25, 2014 · N152CA · Substantial damage
  > The pilot's loss of directional control due a loss of tail rotor effectiveness.
- [NTSB WPR13LA287](https://openairdocs.org/ntsb/WPR13LA287.md): Bell 206B · Royal City, WA · Accident · Serious injuries · Limited investigation · Final report · Jun 24, 2013 · N407FK · Substantial damage
  > The pilot's failure to maintain clearance from netting material during a low pass over trees, which resulted in a loss of helicopter control.
- [NTSB CEN12FA321](https://openairdocs.org/ntsb/CEN12FA321.md): Bell 206-L4 · (Gulf of Mexico) · Accident · 1 fatal · Field investigation · Final report · May 28, 2012 · N7077F · Substantial damage
  > The pilot’s failure to maintain clearance from an obstacle while landing on an obstructed helipad, which resulted in a collision and loss of control. Contributing to the accident was the failure of the helipad owner to mark the helipad closed and the failure…
- [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.

## 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" = '240'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-events/240/cases?engine=03020

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