# NTSB Incident DEN00IA133
> **Diamond Aircraft Industries 20C-1** · 2000-07-01 · SPANISH FORK, UT, USA · NONE
## Event
- **NTSB number:** DEN00IA133
- **Event ID:** 20001212X21430
- **Type:** Incident
- **Date:** 2000-07-01
- **Location:** SPANISH FORK, UT, USA
- **Coordinates:** 40.01984, -111.550804
## Injuries
- **Highest injury:** NONE
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 2
- **Total aboard:** 2
## Aircraft
- **Make:** Diamond Aircraft Industries
- **Model:** 20C-1
- **Registration:** N991CT
- **FAR Part:** 091
- **Engines:** 1
- **Damage:** MINR
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

The company maintenance personnel's inadequate torquing procedures of the propeller attachment bolts which resulted in the fatigue failure of the propeller attachment bolts and the in-flight separation of the propeller.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=DEN00IA133) · AI Analytics · CC0 1.0*