# NTSB Incident CEN17IA094
> **EUROCOPTER DEUTSCHLAND GMBH MBB BK 117 C-2** · 2017-01-27 · Sioux Falls, SD, USA · NONE
## Event
- **NTSB number:** CEN17IA094
- **Event ID:** 20170131X24430
- **Type:** Incident
- **Date:** 2017-01-27
- **Location:** Sioux Falls, SD, USA
- **Coordinates:** 43.578334, -96.748054
## Injuries
- **Highest injury:** NONE
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 3
- **Total aboard:** 3
## Aircraft
- **Make:** EUROCOPTER DEUTSCHLAND GMBH
- **Model:** MBB BK 117 C-2
- **Registration:** N911MK
- **FAR Part:** 135
- **Engines:** 2
- **Damage:** MINR
## Conditions
- **Light:** NITE
- **Weather:** VMC
## Probable cause

The gas generator rear bearing oil scavenge line blocked with coke, which resulted in a failed rear bearing due to an excess of oil lubrication. Contributing to the incident was the operator not completely performing the maintenance items and not utilizing an oil for higher temperatures.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=CEN17IA094) · AI Analytics · CC0 1.0*