# NTSB Accident DEN90FA055
> **MITSUBISHI MU-2B-60** · 1990-02-09 · RAPID CITY, SD, USA · FATL
## Event
- **NTSB number:** DEN90FA055
- **Event ID:** 20001212X22539
- **Type:** Accident
- **Date:** 1990-02-09
- **Location:** RAPID CITY, SD, USA
- **Coordinates:** 44.070594, -103.229591
## Injuries
- **Highest injury:** FATL
- **Fatal:** 1
- **Serious:** 1
- **Minor:** 2
- **Uninjured:** 0
- **Total aboard:** 4
## Aircraft
- **Make:** MITSUBISHI
- **Model:** MU-2B-60
- **Registration:** N64MD
- **FAR Part:** 135
- **Engines:** 2
- **Damage:** SUBS
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

FAILURE OF THE PILOT TO MAINTAIN ADEQUATE AIRSPEED (VMC), WHICH RESULTED IN A LOSS OF AIRCRAFT CONTROL. A FACTOR RELATED TO THE ACCIDENT WAS: FATIGUE FAILURE OF A COUPLING SHAFT IN THE #1 ENGINE, WHICH RESULTED IN LOSS OF POWER IN THAT ENGINE.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=DEN90FA055) · MORVS · CC0 1.0*