# NTSB ATL91LA027: Beech 23C, N5147M, Dunlap, TN, December 8, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: December 8, 1990, 16:23 local (22:23 UTC)
- Place: Dunlap, TN
- Coordinates: 35.370761, -85.379501 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.3708&lon=-85.3795&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report December 14, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 8360
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL91LA027
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8360/pdf
- Page: https://openairdocs.org/ntsb/ATL91LA027

## Probable cause

THE PILOT'S FAILURE TO USE THE CARBURETOR HEAT PROPERLY, WHICH RESULTED IN THE FORMATION OF CARBURETOR ICE, FOLLOWED BY A COMPLETE LOSS OF ENGINE POWER. FACTORS TO THIS ACCIDENT WERE CARBURETOR ICING CONDITIONS AND THE ROUGH AND UNEVEN TERRAIN AT THE CRASH SITE.

## Analysis

WHILE CRUISING AT 4000 FEET, THE ENGINE QUIT. THE PILOT ATTEMPTED TO RESTART THE ENGINE, BUT FAILED. THE AIRPLANE CRSHED IN A ROCK PIT WHERE IT SUSTAINED MAJOR STRUCTURAL DAMAGE TO THE UNDERCARRIAGE. FUEL WAS IN BOTH TANKS WHEN EXAMINED AT THE ACCIDENT SITE. THE AIRPLANE EXAMINATION ALSO FAILED TO DISCLOSE ANY MECHANICAL PROBLEM WHICH WOULD HAVE PREVENTED NORMAL OPERATION. THE ENGINE OPERATED NORMALLY DURING THE FUNCTIONAL EXAMINATION. HOWEVER, THE ICING PROBABILITY CURVE INDICATED THE POSSIBILITY OF CARBURETOR ICE FORMATION. THE AIRPLANE WAS EQUIPPED WITH AN OPERATIONAL CARBURETOR HEAT SYSTEM.

## Sequence of events

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

- Loss of engine power(total) - nonmechanical, cruise - normal
  - weather condition - carburetor icing conditions (contributing factor)
  - carburetor heat - improper use of, pilot in command (cause)
- Forced landing, descent - emergency
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - rough/uneven (contributing factor)

## Aircraft

- Registration: [N5147M](https://openairdocs.org/deregistered/N5147M-1993-06-16), registration cancelled 1993-06-16, S/N M2035 (OpenAirDocs)
- Reported make and model: BEECH 23C
- Registry model: [Beech C23](https://openairdocs.org/model/beech-c23) (registry code 1151242) (OpenAirDocs)
- Category: Airplane
- Serial number: M-2035
- Airframe hours: 2600
- Engines: LYCOMING O-360-A4K 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Winchester, John L.
- Departed: CHA, CHATTANOOGA, TN
- Destination: M54, LEBANON, TN
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; flight hours: 3,395 total, 25 in this make and model, 3,000 as pilot in command, 30 in the last 90 days, 2 in the last 30 days

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 135° at 8 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 52 °F, dew point 12 °F
- Observed at: CHA, 37 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 19901208053259A](https://openairdocs.org/incident/19901208053259A), Dec 8, 1990: Beech C23, Dunlap, TN, Substantial damage. Engine quit en route. Crash landed in gravel pit. No engine defects. Conditions good for carburetor icing.

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

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