# NTSB ATL84FA100: Bell 47GL, N12KH, Cullman, AL, February 17, 1984

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: February 17, 1984, 09:04 local (15:04 UTC)
- Place: Cullman, AL
- Coordinates: 34.260147, -86.60958 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.2601&lon=-86.6096&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 6255
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL84FA100
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/6255/pdf
- Page: https://openairdocs.org/ntsb/ATL84FA100

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, maneuvering
  - lubricating system - contamination (cause)
  - maintenance,overhaul - improper, unqualified person (cause)
  - fluid,oil - starvation (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - ground
  - terrain condition - rising (contributing factor)

## Analysis

THE PLT HAD JUST COMPLETED AN ENG OVERHAUL & WAS TEST FLYING THE HELICOPTER. WHILE MANEUVERING AT APRX 100 FT AGL, THE ENG LOST POWER & THE PLT INITIATED AN AUTOROTATION. DURING THE LANDING, THE HELICOPTER IMPACTED HARD ON RISING TERRAIN, ROLLED ONTO ITS SIDE & BURNED. AN INVESTIGATION REVEALED THAT THE ENG HAD SEIZED. CONTAMINATION HAD ENTERED THE OIL SYSTEM DURING THE OVERHAUL WHICH HAD RESULTED IN THE SEIZURE. THE PLT WAS NOT A CERTIFIED POWERPLANT MECHANIC.

## Aircraft

- Registration: N12KH (not matched to a registry record)
- Reported make and model: BELL 47GL
- Category: Helicopter
- Serial number: CC1-73-1
- Airframe hours: 1084
- Engines: LYCOMING VO-435-A1F 260 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Part 91
- Registered owner: Billy Don Walker
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, April 1, 1983

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 29; commercial; airplane ratings: single-engine land, multi-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: center; toxicology performed; flight hours: 4,197 total, 11 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F

## 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 19840217004369A](https://openairdocs.org/incident/19840217004369A), Feb 17, 1984: Bell OH13H, Cullman, AL, Destroyed. Unauthorized overhaul by pilot caused engine failure. Contaminants found in rod bearings. Piston pins froze in rods

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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