# NTSB Accident CHI91DER13
> **BELL 47G-3B-1** · 1991-08-09 · MAPLE GROVE, MN, USA · NONE
## Event
- **NTSB number:** CHI91DER13
- **Event ID:** 20001212X17795
- **Type:** Accident
- **Date:** 1991-08-09
- **Location:** MAPLE GROVE, MN, USA
- **Coordinates:** 45.130474, -93.450279
## Injuries
- **Highest injury:** NONE
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 1
- **Total aboard:** 1
## Aircraft
- **Make:** BELL
- **Model:** 47G-3B-1
- **Registration:** N73998
- **FAR Part:** 137
- **Engines:** 1
- **Damage:** SUBS
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

THE PILOT'S FAILURE TO MAINTAIN DIRECTIONAL CONTROL OF THE HELICOPTER DURING THE FORCED LANDING.  RELATED FACTORS ARE THE LOSS OF ENGINE POWER, LOSS OF ROTOR RPM, THE ERODED COMPRESSOR BLADES, THE PILOT'S OPERATION WITH KNOWN DEFICIENCIES IN EQUIPMENT AND INADEQUATE AIRCRAFT PREFLIGHT, AND THE BLOCKED SPRAY EQUIPMENT.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=CHI91DER13) · AI Analytics · CC0 1.0*