# NTSB Accident WPR17LA188
> **ROBINSON HELICOPTER COMPANY R44 II** · 2017-08-26 · El Dorado Hills, CA, USA · MINR
## Event
- **NTSB number:** WPR17LA188
- **Event ID:** 20170826X21023
- **Type:** Accident
- **Date:** 2017-08-26
- **Location:** El Dorado Hills, CA, USA
- **Coordinates:** 38.723888, -121.070274
## Injuries
- **Highest injury:** MINR
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 2
- **Uninjured:** 0
- **Total aboard:** 2
## Aircraft
- **Make:** ROBINSON HELICOPTER COMPANY
- **Model:** R44 II
- **Registration:** N61NM
- **FAR Part:** 091
- **Engines:** 1
- **Damage:** SUBS
## Conditions
- **Light:** DUSK
- **Weather:** VMC
## Probable cause

Maintenance personnel's inadequate routine maintenance on the helicopter engine, which led to low cylinder compression, improper magneto timing, and camshaft lobe wear, which subsequently resulted in degraded engine performance.

---
*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=WPR17LA188) · AI Analytics · CC0 1.0*