# NTSB MKC90LA083: Bell 47G-2, N4779U, Harrisburg, AR, April 12, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: April 12, 1990, 01:45 local (06:45 UTC)
- Place: Harrisburg, AR
- Coordinates: 35.56007, -90.719429 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.5601&lon=-90.7194&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report March 5, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 34958
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC90LA083
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34958/pdf
- Page: https://openairdocs.org/ntsb/MKC90LA083

## Probable cause

FAILURE OF THE GENERATOR, AND FAILURE OF THE PILOT TO MAINTAIN ROTOR RPM.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering - aerial application
  - electrical system,generator - failure,total (cause)
  - instrument light(s) - inoperative
  - rotor rpm - not maintained, pilot in command (cause)
- Forced landing, maneuvering - turn to landing area (emergency)
- In flight collision with terrain/water, landing
  - light condition - night (contributing factor)
  - run on landing - attempted, pilot in command

## Analysis

THE PILOT SAID THAT WHILE FLYING AT LOW ALTITUDE OVER A PEACH ORCHARD TO PREVENT FROST DAMAGE, THE INSTRUMENT PANEL LIGHTS DIMMED.  ALSO, HE REPORTED THAT WITH THE RESTRICTED INSTRUMENT VISIBILITY, THE HELICOPTER 'GOT BEHIND THE POWER CURVE' AND THE ROTOR RPM DECAYED.  SUBSEQUENTLY, A RUN-ON LANDING WAS MADE, AND THE HELICOPTER WAS DAMAGED.  A POST-ACCIDENT INVESTIGATION REVEALED THE GENERATOR HAD FAILED.

## Aircraft

- Registration: N4779U (not matched to a registry record)
- Reported make and model: BELL 47G-2
- Category: Helicopter
- Serial number: 622
- Airframe hours: 1450
- Engines: FRANKLIN 6VS-335-A 210 horsepower reciprocating
- Damage: Substantial damage
- Flight: Other work use, Part 137
- Operator: Barr, Donald M
- Registered owner: Barr, Don M
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, December 1, 1989, 15 hours before
- Departed: HARRISBURG, AR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 34; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 2,161 total, 1,722 in this make and model

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: calm
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 34 °F, dew point -0 °F
- Altimeter: 29.00 inHg

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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