# NTSB DEN89LA221: Mooney M20C, N3456X, Neihart, MT, September 18, 1989

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: September 18, 1989, 07:22 local (13:22 UTC)
- Place: Neihart, MT
- Coordinates: 46.889499, -110.719978 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.8895&lon=-110.7200&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report January 22, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 17785
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN89LA221
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17785/pdf
- Page: https://openairdocs.org/ntsb/DEN89LA221

## Probable cause

VFR FLIGHT BY THE PILOT INTO INSTRUMENT METEOROLOGICAL CONDITIONS (IMC) AND HIS FAILURE TO MAINTAIN SUFFICIENT ALTITUDE.  RELATED FACTORS WERE:  THE HIGH TERRAIN AND ADVERSE WEATHER CONDITIONS.

## Sequence of events

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

- In flight encounter with weather, cruise
  - weather condition - clouds (contributing factor)
  - weather condition - low ceiling (contributing factor)
  - weather condition - fog (contributing factor)
  - weather condition - rain (contributing factor)
  - vfr flight into imc - continued, pilot in command (cause)
- In flight collision with object, descent
  - terrain condition - high terrain (contributing factor)
  - terrain condition - tree(s) (contributing factor)
  - proper altitude - not maintained, pilot in command (cause)

## Analysis

THE INSTRUMENT RATED COMMERCIAL PILOT REPORTED THAT HE WAS CRUISING AT 14,500 FEET WHEN HE ENCOUNTERED CLOUDS. HE DESCENDED TO 12,500 FEET AND THEN TO 11,000 FEET IN AN EFFORT TO AVOID THE WEATHER. HE STATED 'I DESCENDED DOWN TO ELEVEN THOUSAND AND THE TREES CAME RIGHT UP ON ME. I WAS VFR, DIDN'T FILE A FLIGHT PLAN . . .' ELEVATION OF THE CRASH SITE WAS 9175 FEET.

## Aircraft

- Registration: [N3456X](https://openairdocs.org/deregistered/N3456X-1989-09-18), registration cancelled 1989-09-18, S/N 3411, built 1966 (OpenAirDocs)
- Reported make and model: MOONEY M20C
- Registry model: [Mooney M20C](https://openairdocs.org/model/mooney-m20c) (registry code 5870208) (OpenAirDocs)
- Category: Airplane
- Serial number: 3411
- Engines: LYCOMING O-360-A1D 180 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Finster, John N.
- Airworthiness certificate: Standard, Normal
- Departed: MT02, HARDIN, MT
- Destination: LWS, LEWISTON, ID

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, expired; flight hours: 1,632 total

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 310° at 9 knots
- Temperature: -0 °F, dew point 10 °F
- Altimeter: 29.00 inHg
- Observed at: GTF, 43 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 19890918035389A](https://openairdocs.org/incident/19890918035389A), Sep 18, 1989: Mooney M20C, Neihart, MT, Destroyed. Reported was on top when weather deteriorated, descended into trees on mountain top. Reported he was VFR at impact.

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.