# NTSB DEN87LA125: Cessna 170B, N1979C, Big Sky, MT, May 16, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 16, 1987, 12:00 local (18:00 UTC)
- Place: Big Sky, MT
- Coordinates: 45.25922, -111.320655 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.2592&lon=-111.3207&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report August 31, 1988
- Report: Approved by Office Director
- NTSB case key (mKey): 17225
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN87LA125
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17225/pdf
- Page: https://openairdocs.org/ntsb/DEN87LA125

## Sequence of events

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

- In flight encounter with weather, cruise - normal
  - weather condition - low ceiling (contributing factor)
  - weather condition - fog (contributing factor)
  - weather condition - obscuration (contributing factor)
  - weather evaluation - disregarded, pilot in command (cause)
  - flight into known adverse weather - continued, pilot in command (cause)
  - precautionary landing - attempted, pilot in command
- Loss of control - on ground/water, landing - roll
  - terrain condition - wet (contributing factor)
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - dirt bank/rising embankment (contributing factor)
  - landing gear,main gear - overload (contributing factor)

## Analysis

THE PRIVATE PLT WAS FLYING CROSS COUNTRY IN DETERIORATING WEATHER CONDITIONS. FOG WAS FORECAST AND LIGHT RAIN WAS IN PROGRESS. THE FLT ENCOUNTERED LESS THAN VFR CONDITIONS IN A MOUNTAINOUS AREA AND REVERSED COURSE. WEATHER WAS BELOW VFR ON THE REVERSE COURSE ALSO. THE PLT ELECTED TO CIRCLE FOR AN HOUR WAITING FOR VFR CONDITIONS. A PRECAUTIONARY LANDING WAS ATTEMPTED TO A LOGGING ROAD. DURING ROLL OUT, THE ACFT DEPARTED THE ROAD TO THE LEFT AND THE LEFT MAIN GEAR STRUCK AN EMBANKMENT AND FAILED. THE ACFT PIVOTED TO THE LEFT AND CAME TO REST LEFT WING DOWN.

## Aircraft

- Registration: [N1979C](https://openairdocs.org/deregistered/N1979C-2018-01-11), registration cancelled 2018-01-11, S/N 26124, built 1953 (OpenAirDocs)
- Reported make and model: CESSNA 170B
- Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs)
- Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 26124
- Airframe hours: 4950
- Engines: CONTINENTAL O-300 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Doug S. Chapman
- Registered owner: Chapman, Doug S.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, September 10, 1986, 10 hours before
- Departed: 29S, GARDINER, MT
- Destination: 6S5, HAMILTON, MT
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 24; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 300 total, 11 in this make and model, 247 as pilot in command, 44 in the last 90 days, 4 in the last 30 days

## Weather

- Conditions: Instrument (IMC), Day
- Wind: calm
- Visibility: 1 statute miles
- Lowest ceiling: 750 ft
- Temperature: 57 °F, dew point 57 °F

## 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 19870516013479A](https://openairdocs.org/incident/19870516013479A), May 16, 1987: Cessna 170B, Big Sky, MT, Substantial damage. Encountered deteriorating weather en route. Precautionary landing on road. Veered left striking an embankment.

## Other investigations on N1979C (1)

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.

- [NTSB SEA03CA155](https://openairdocs.org/ntsb/SEA03CA155), Jul 27, 2003: Cessna 170B (N1979C), Schafer, MT, substantial damage. Probable cause: The pilot's delayed remedial action during the takeoff roll. Factors include wet terrain, a fence and an embankment located at the end of the runway.

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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