# NTSB Accident ANC18LA058
> **Robinson R44** · 2018-07-29 · Bettles, AK, USA · NONE
## Event
- **NTSB number:** ANC18LA058
- **Event ID:** 20180731X84010
- **Type:** Accident
- **Date:** 2018-07-29
- **Location:** Bettles, AK, USA
- **Coordinates:** 66.860557, -151.645278
## Injuries
- **Highest injury:** NONE
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 3
- **Total aboard:** 3
## Aircraft
- **Make:** Robinson
- **Model:** R44
- **Registration:** N744AK
- **FAR Part:** PUBU
- **Engines:** 1
- **Damage:** SUBS
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

Maintenance personnel's application of insufficient preload on the attachment hardware for the idler gear shaft during engine overhaul, which resulted in the dismounting of the idler gear shaft assembly due to wear and deformation and the subsequent total loss of engine power. Contributing to the accident was a mechanic's failure to identify metallic particles contained in the oil filter element at the most recent 100-hour inspection.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=ANC18LA058) · AI Analytics · CC0 1.0*