# NTSB CHI89LA063: Beech 95-B-55, N27WF, Crothersville, IN, March 26, 1989

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: March 26, 1989, 15:30 local (21:30 UTC)
- Place: Crothersville, IN
- Coordinates: 38.790889, -85.839622 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.7909&lon=-85.8396&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed, report July 11, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 14332
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI89LA063
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14332/pdf
- Page: https://openairdocs.org/ntsb/CHI89LA063

## Probable cause

A FAILURE OF THE ENGINE DUE TO A CRANKSHAFT COUNTERWEIGHT FAILURE. THE PILOT PERFORMED EMERGENCY PROCEDURES AND EXECUTED A FORCED LANDING IN AN OPEN FIELD, WHERE THE AIRCRAFT ENCOUNTERED A LARGE MUDDY AREA, BOGGED DOWN AND NOSED OVER.

## 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, cruise - normal
  - eng assembly,crankshaft counterweights/vib damper - failure,total (cause)
  - maintenance,recordkeeping - poor, pilot in command
  - powerplant - failure,total (cause)
  - emergency procedure - performed, pilot in command
- Forced landing, descent - emergency
- Nose over, landing - roll
  - terrain condition - open field (contributing factor)
  - terrain condition - wet (contributing factor)
  - landing gear,nose gear - overload

## Analysis

DURING A LOCAL PLEASURE FLIGHT, WHILE IN NORMAL CRUISE, THE RIGHT ENGINE FAILED TOTALLY. THE PILOT REDUCED POWER ON THE LEFT (OPERATING) ENGINE TO 'CURTAIL THE VIOLENT VIBRATION OF THE AIRCRAFT' AND EXECUTED A FORCED LANDING IN AN OPEN FIELD. AS THE AIRCRAFT WAS ROLLING OUT AFTER TOUCHDOWN, IT ENCOUNTERED A MUDDY AREA. THE NOSE GEAR BOGGED DOWN, THEN COLLAPSED, AND THE AIRCRAFT NOSED OVER. POST-ACCIDENT EXAMINATION OF THE RIGHT ENGINE REVEALED THAT THE PIN RETAINING PLATE CUT THROUGH THE CRANKSHAFT COUNTERWEIGHT, RELEASING IT. FURTHER EXAMINATION REVEALED THAT THE COUNTERWEIGHTS HAD NOT BEEN 'TUFTRIDED', A SURFACE HARDENING PROCESS WHICH PREVENTS THE PIN RETAINING PLATE FROM CUTTING/WEARING THROUGH THE COUNTERWEIGHT. THIS PROCESS HAS BEEN REQUIRED ON NEW ENGINES SINCE 1968, AND ON REBUILT ENGINES SINCE 1973-74. THE ACCIDENT ENGINE WAS REBUILT BY THE MANUFACTURER IN 1971. LOGBOOK/MAINTENANCE INFORMATION PROVIDED BY THE PILOT WAS INCOMPLETE.

## Aircraft

- Registration: [N27WF](https://openairdocs.org/deregistered/N27WF-2013-06-06), registration cancelled 2013-06-06, S/N TC-694, built 1964 (OpenAirDocs)
- Reported make and model: BEECH 95-B-55
- Registry model: [Beech 95-B55 (T42A)](https://openairdocs.org/model/beech-95-b55-t42a) (registry code 1152706) (OpenAirDocs)
- Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: TC-694
- Airframe hours: 4645
- Engines: CONTINENTAL IO-470-L 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Casebolt, Fon
- Registered owner: Casebolt, Fon
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 18, 1988, 50 hours before
- Departed: BQM, LOUISVILLE, KY
- Destination: BQM, LOUISVILLE, KY

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 52; private; airplane ratings: multi-engine land, single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 474 total, 137 in this make and model, 332 as pilot in command, 10 in the last 90 days, 2 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Dawn
- Wind: 160° at 10 knots
- Visibility: 7 statute miles
- Lowest ceiling: none
- Temperature: 79 °F, dew point 52 °F
- Altimeter: 30.00 inHg
- Observed at: LOU, 32 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 19890326004529A](https://openairdocs.org/incident/19890326004529A), Mar 26, 1989: Beech 95B55, Crothersville, IN, Substantial damage. Crankshaft counterweight came off and tore apart engine. Nosed over landing in soft mud. Part not secured per AD.

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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