# NTSB Accident WPR12TA364
> **AMERICAN EUROCOPTER LLC AS350B3** · 2012-08-18 · Sunburst, MT, USA · NONE
## Event
- **NTSB number:** WPR12TA364
- **Event ID:** 20120821X32707
- **Type:** Accident
- **Date:** 2012-08-18
- **Location:** Sunburst, MT, USA
- **Coordinates:** 48.885833, -111.89611
## Injuries
- **Highest injury:** NONE
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 2
- **Total aboard:** 2
## Aircraft
- **Make:** AMERICAN EUROCOPTER LLC
- **Model:** AS350B3
- **Registration:** N3939A
- **FAR Part:** PUBU
- **Engines:** 1
- **Damage:** SUBS
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

The improper installation of the engine-to-main gearbox flex coupling, which resulted in the failure of the flex coupling and a loss of power to the rotor system during takeoff.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=WPR12TA364) · AI Analytics · CC0 1.0*