# NTSB DEN84IA281: Mooney M20F, N9121V, Saratoga, WY, September 5, 1984

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: September 5, 1984, 10:00 local (16:00 UTC)
- Place: Saratoga, WY
- Coordinates: 41.450744, -106.810188 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.4507&lon=-106.8102&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16276
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN84IA281
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16276/pdf
- Page: https://openairdocs.org/ntsb/DEN84IA281

## 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
  - reason for occurrence undetermined (cause)
  - maintenance,service bulletin/letter - not followed
  - fluid,oil - starvation (contributing factor)
  - engine assembly,crankshaft - overtemperature (contributing factor)
  - engine assembly,crankshaft - fatigue (cause)
- Forced landing, descent - emergency
- Gear collapsed, landing - roll
  - airport/facilities - rough/uneven (contributing factor)
  - terrain condition - mountainous/hilly (contributing factor)

## Analysis

WHILE IN LEVEL CRUISE FLT AT 10500 FT, THE PLT HEARD A HIGH-PITCHED WHINE THAT LASTED FOR ABOUT 5 SECONDS. THE ENGINE THEN SEIZED AND THE PLT MADE A FORCED LANDING IN MOUNTAINOUS FOOTHILLS. DURING THE LANDING ROLL, THE LANDING GEARCOLLAPSED. EXAMINATION OF THE DISASSEMBLED ENGINE REVEALED EVIDENCE OF HIGH HEAT DISTRESS AND A FRACTURED CRANKSHAFT. DETAILED EXAMINATION OF THE CRANKSHAFT REVEALED EVIDENCE OF A LACK OF LUBRICATION AND FATIGUE. MAINTENANCE RECORDS REVEALED THAT THE ACFT WAS INVOLVED IN A GEAR COLLAPSE INCIDENT IN 1977 THAT RESULTED IN A PROP STRIKE AND SUDDEN ENGINESTOPPAGE. THE ENGINE WAS NOT DISASSEMBLED AND INSPECTED AT THAT TIME AS SUGGESTED BY AVCO LYCOMING SERVICE LETTER NO. L163B.

## Aircraft

- Registration: [N9121V](https://openairdocs.org/aircraft/N9121V), registered now, S/N 690029, built 1969 (OpenAirDocs)
- Reported make and model: MOONEY M20F
- Registry model: [Mooney M20F](https://openairdocs.org/model/mooney-m20f) (registry code 5870214) (OpenAirDocs)
- Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 690029
- Engines: LYCOMING IO-360-A1A 180 horsepower reciprocating
- Damage: Minor damage
- Flight: Business, Part 91
- Operator: Robert B Anderson Jr
- Registered owner: Robert B. Anderson, Jr.
- Airworthiness certificate: Standard, Normal
- Departed: FML, FORT COLLINS, CO
- Destination: PIH, POCATELLO, ID
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 63; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 7,842 total, 5,842 in this make and model, 7,842 as pilot in command, 41 in the last 90 days, 41 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 60° at 5 knots
- Visibility: 60 statute miles
- Lowest ceiling: none
- Temperature: 72 °F, dew point 39 °F
- Altimeter: 30.00 inHg
- Observed at: RWL, 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).

- [Incident 19840905076689I](https://openairdocs.org/incident/19840905076689I), Sep 5, 1984: Mooney M20F, Saratoga, WY, Minor damage. Engine seized after pilot heard high pitched whine in flight. Landed on a foothill. Crankshaft had failed.

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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