# NTSB SEA90LA048: Bell BH-47G3B2, N4073G, Des Moines, WA, March 1, 1990

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: March 1, 1990, 15:50 local (23:50 UTC)
- Place: Des Moines, WA
- Coordinates: 47.380325, -122.309928 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.3803&lon=-122.3099&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report February 12, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41171
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA90LA048
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41171/pdf
- Page: https://openairdocs.org/ntsb/SEA90LA048

## Probable cause

PARTIAL LOSS OF ENGINE POWER, CAUSE UNDETERMINED. THE AIRCRAFT WAS NOT RECOVERED AND EXAMINATION OF THE ENGINE WAS NOT POSSIBLE.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power, cruise - normal
  - reason for occurrence undetermined (cause)
- Forced landing, cruise - normal
- Ditching, descent - emergency

## Analysis

THE ENGINE BEGAN RUNNING ROUGH DURING CRUISE FLIGHT AND RPM DECREASED FROM 3200 TO 2800. THE PILOT WAS NOT ABLE TO REACH SHORE WITH THE AVAILABLE POWER AND DITCHED THE AIRCRAFT IN A SALTWATER BAY. HE WAS RECOVERED FROM THE WATER BY A PRIVATE BOAT. THE AIRCRAFT SANK IN 300 FT. DEEP WATER AND WAS NOT RECOVERED.

## Aircraft

- Registration: [N4073G](https://openairdocs.org/deregistered/N4073G-2012-11-19), registration cancelled 2012-11-19, S/N 6703, built 1968 (OpenAirDocs)
- Reported make and model: BELL BH-47G3B2
- Registry model: [Bell 47G-3B-2](https://openairdocs.org/model/bell-47g-3b-2) (registry code 1181029) (OpenAirDocs)
- Registry engine: [Lycoming TVO-435-GIA](https://openairdocs.org/engine/lycoming-tvo-435-gia) (registry code 41526, turbo-prop) (OpenAirDocs)
- Category: Helicopter
- Serial number: 6703
- Airframe hours: 6204
- Engines: LYCOMING VO-435 280 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Richard H. Butz
- Airworthiness certificate: Standard, Normal
- Last inspection: Unknown, August 16, 1989, 36 hours before
- Departed: S50, AUBURN, WA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 14,900 total, 1,600 in this make and model, 40 in the last 90 days, 12 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 6 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 61 °F, dew point 30 °F
- Altimeter: 30.00 inHg
- Observed at: SEA, 5 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19900301052099A](https://openairdocs.org/incident/19900301052099A), Mar 1, 1990: Bell 47G3B2, Des Moines, WA, Destroyed. Engine lost power at cruise. Ditched in 300 feet of water. Helicopter sank. Cause power loss unknown.

## Other investigations on N4073G (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB DEN86LA119](https://openairdocs.org/ntsb/DEN86LA119), Apr 25, 1986: Bell 47G-3B-2 (N4073G), Santa Fe, NM, substantial damage

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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