# NTSB Accident WPR14LA308
> **MDHI 369D** · 2014-07-22 · Oso, WA, USA · SERS
## Event
- **NTSB number:** WPR14LA308
- **Event ID:** 20140722X53457
- **Type:** Accident
- **Date:** 2014-07-22
- **Location:** Oso, WA, USA
- **Coordinates:** 48.233333, -121.916664
## Injuries
- **Highest injury:** SERS
- **Fatal:** 0
- **Serious:** 1
- **Minor:** 0
- **Uninjured:** 0
- **Total aboard:** 1
## Aircraft
- **Make:** MDHI
- **Model:** 369D
- **Registration:** N5225C
- **FAR Part:** 133
- **Engines:** 1
- **Damage:** SUBS
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

The pilot/mechanic’s failure to properly perform required inspections of the main rotor blades at the necessary intervals, which resulted in an in-flight separation of a main rotor blade due to disbonding and fatigue cracking. Contributing to the accident was the lack of clear guidance in the helicopter maintenance inspection instructions, which allowed for the possible misinterpretation by maintenance personnel of their intent.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=WPR14LA308) · AI Analytics · CC0 1.0*