# NTSB BFO92FA152: Mooney M20K, N99693, Weston, WV, September 21, 1992

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: September 20, 1992, 20:01 local (Sep 21, 1992, 00:01 UTC)
- Place: Weston, WV
- Coordinates: 39.039047, -80.459503 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.0390&lon=-80.4595&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report September 28, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 11738
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO92FA152
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/11738/pdf
- Page: https://openairdocs.org/ntsb/BFO92FA152

## Probable cause

TOTAL LOSS OF ENGINE POWER DUE TO THE INADEQUATE TORQUE OF THE NO. 1 CYLINDER ATTACH BOLTS AND STUDS, FATIQUE FAILURE OF THE BOLTS/STUDS, AND SEPARATION OF THE NO. 1 CYLINDER.  FACTORS RELATED TO THE ACCIDENT WERE: DARKNESS AND HILLY TERRAIN, WHICH WERE UNSUITABLE FOR A FORCED LANDING.

## 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
  - engine assembly,cylinder - fatigue (cause)
  - engine assembly,cylinder - separation (cause)
  - engine assembly,cylinder - undertorqued (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing
  - light condition - dark night (contributing factor)
  - terrain condition - mountainous/hilly (contributing factor)

## Analysis

AFTER BEING ALERTED TO AN OIL STREAK ALONG THE SIDE OF THE AIRPLANE, THE PILOT CHECKED THE OIL AND THEN DEPARTED ON A NIGHT FLIGHT OVER HILLY TERRAIN.  WHILE IN CRUISE FLIGHT, THE PILOT REPORTED 'MOTOR TROUBLES' TO APPROACH CONTROL AND RECEIVED VECTORS TO THE CLOSEST AIRPORT.  THIS AIRPORT HAD NO RUNWAY LIGHTING.  THE PILOT WAS ABLE TO MAINTAIN PARTIAL POWER FOR ABOUT 14 MINUTES.  DURING THIS TIME, THE ATC CONTROLER WAS UNSUCCESSFUL IN ATTEMPTS TO TURN ON THE RUNWAY LIGHTS AT THE CLOSEST AIRPORT, AND WAS UNAWARE THE LIGHTS WERE OUT OF SERVICE.  THE PILOT THEN REPORTED 'ITS DEAD' AS HE APPROACHED THE AIRPORT.  HE WAS UNABLE TO LAND AT THE UNLIT AIRPORT, DESPITE GUIDANCE FROM ATC AND ANOTHER AIRPLANE WHICH WAS IN THE VICINITY.  THE AIRPLANE IMPACTED TERRAIN AND WAS DESTROYED.  AN EXAM OF THE ENGINE REVEALED THE NO. 1 CYLINDER HAD SEPARATED FROM THE ENGINE CRANKCASE IN FLIGHT.  A METALLURGICAL EXAM REVEALED EVIDENCE OF FRETTING DAMAGE ON THE ATTACHMENT FLANGE AND FATIGUE FAILURE OF THE ATTACHING THROUGH BOLTS AND HOLD DOWN STUDS.

## Aircraft

- Registration: [N99693](https://openairdocs.org/deregistered/N99693-1997-08-21), registration cancelled 1997-08-21, S/N 250548 (OpenAirDocs)
- Reported make and model: MOONEY M20K
- Registry model: [Mooney M20K](https://openairdocs.org/model/mooney-m20k) (registry code 5870220) (OpenAirDocs)
- Category: Airplane
- Serial number: 25-0548
- Airframe hours: 1500
- Engines: CONTINENTAL TSIO-360-GB3 180 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: T And S Rentals
- Registered owner: T And S Rentals
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, February 25, 1992
- Departed: CRW, CHARLESTON, WV
- Destination: MGW, MORGANTOWN, WV
- Airport: 49I, Louis Bennett Field

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 64; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 1,200 total, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: calm
- Visibility: 12 statute miles
- Lowest ceiling: 20,000 ft broken
- Temperature: 72 °F, dew point 66 °F
- Altimeter: 30.00 inHg
- Observed at: CKB, 17 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 19920920037719A](https://openairdocs.org/incident/19920920037719A), Sep 20, 1992: Mooney M20K, Weston, WV, Destroyed, 2 fatal. Disregarded oil streaks from engine. Lost power en route. Crashed trying for airport. Cylinder holddown studs broke

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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