# NTSB ATL92LA154: Weatherly 620A, N4650W, Cobb, GA, August 9, 1992

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: August 9, 1992, 11:30 local (15:30 UTC)
- Place: Cobb, GA
- Coordinates: 31.95919, -83.959152 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=31.9592&lon=-83.9592&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report July 29, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 8641
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL92LA154
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8641/pdf
- Page: https://openairdocs.org/ntsb/ATL92LA154

## Probable cause

THE CORRODED, AND SEPARATED, MAGNETIC CHIP DETECTOR PLUG WHICH ALLOWED THE LOSS OF ALL ENGINE OIL AND THE ENGINE'S SUBSEQUENT SEIZURE. FACTORS WERE THE INADEQUATE 100 HOUR INSPECTION, AND THE HIGH VEGETATION IN THE FORCED LANDING FIELD.

## 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 - aerial application
  - lubricating system,oil magnetic plug - corroded (cause)
  - maintenance,100-hour inspection - inadequate, company maintenance personnel (contributing factor)
  - fluid,oil - exhaustion (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, descent - emergency
  - terrain condition - crop
- Nose over, landing - roll
  - terrain condition - high vegetation (contributing factor)

## Analysis

WHILE CONDUCTING AN AERIAL APPLICATION FLIGHT, THE ENGINE SEIZED & A FORCED LANDING WAS MADE INTO A CORN FIELD. THE AIRPLANE NOSED OVER DURING THE LANDING ROLL. EXAMINATION OF THE AIRPLANE REVEALED THAT ENGINE OIL COVERED ITS BELLY. THE CHIP DETECTOR IN THE OIL SUMP OF THE ENGINE WAS FOUND BROKEN, WITH THE DETECTOR ELECTRODE HELD ON BY ITS TRANSMISSION WIRE. THE OPEN DETECTOR PORT HAD ALLOWED ALL OF THE ENGINE OIL TO ESCAPE. METALLURGICAL EXAMINATION OF THE DETECTOR ELECTRODE REVEALED THAT IT HAD SEPARATED BECAUSE OF CORROSION. THE OPERATOR'S MECHANIC STATED THAT HE USUALLY FOUND ABOUT ONE TABLESPOON OF WATER IN THE ENGINE SUMP DURING 100 HOUR OIL CHANGES.

## Aircraft

- Registration: [N4650W](https://openairdocs.org/deregistered/N4650W-2018-03-02), registration cancelled 2018-03-02, S/N 1539, built 1992 (OpenAirDocs)
- Reported make and model: WEATHERLY 620A
- Registry model: [Weatherly 620A](https://openairdocs.org/model/weatherly-620a) (registry code 9630603) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 1539
- Airframe hours: 300
- Engines: P&W R-985 450 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Varner Bass Aviation, Inc
- Registered owner: Varner Bass Aviation, Inc
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: 100 hour, July 11, 1992, 100 hours before
- Departed: NONE, LEESBURG, GA
- Destination: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 3,900 total, 500 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 3 knots
- Visibility: 7 statute miles
- Lowest ceiling: 10,000 ft broken
- Temperature: 84 °F, dew point 72 °F
- Altimeter: 30.00 inHg
- Observed at: ABY, 15 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 19920809033189A](https://openairdocs.org/incident/19920809033189A), Aug 9, 1992: Wthrly 620, Cobb, GA, Substantial damage. Lost oil during spray runs. Engine seized. Nosed over landing. Chip detector plug came out causing oil loss.

## Other investigations on N4650W (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 CHI03LA134](https://openairdocs.org/ntsb/CHI03LA134), May 24, 2003: Weatherly 620A (N4650W), Melville, ND, substantial damage. Probable cause: The pilot's failure to maintain clearance from the wires. The low altitude operation and the wires were contributing factors.

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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