# NTSB DEN85LA181: Cessna 170B, N2432D, Swan Lake, MT, July 6, 1985

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 5, 1985, 18:00 local (Jul 6, 1985, 00:00 UTC)
- Place: Swan Lake, MT
- Coordinates: 47.740287, -113.740089 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.7403&lon=-113.7401&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): 16718
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN85LA181
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16718/pdf
- Page: https://openairdocs.org/ntsb/DEN85LA181

## Sequence of events

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

- Loss of engine power(total) - nonmechanical, cruise - normal
  - fluid,fuel - exhaustion (contributing factor)
  - fuel supply - misjudged, pilot in command (cause)
  - fuel system,line - deteriorated (cause)
  - fuel supply - not identified, pilot in command (contributing factor)
  - fuel system,line - leak (cause)
  - maintenance,replacement - improper, other maintenance personnel (contributing factor)
- Forced landing, descent - emergency
- On ground/water collision with object, landing - roll
  - terrain condition - high terrain (contributing factor)
  - terrain condition - mountainous/hilly (contributing factor)
  - airport facilities,runway/landing area condition - ground (contributing factor)
  - airport facilities,runway/landing area condition - loose gravel/sandy (contributing factor)
  - airport facilities,runway/landing area condition - none suitable (contributing factor)
  - object - tree(s) (contributing factor)

## Analysis

THE PLT SAID THAT PRIOR TO DEPARTURE THERE WAS AN ESTIMATED 14 GALS OF FUEL ON BOARD. AFTER APRX 30 MINUTES OF FLIGHT THE ENG LOST ALL PWR AND A FORCED LANDING WAS ACCOMPLISHED IN A MOUNTAINOUS CREEK BED. DURING THE LANDING ROLL THE ACFT STRUCK A FEELED TREE AND OVERTURNED. POST-CRASH EXAM OF THE ACFT REVEALED ONLY TRACE AMOUNTS OF FUEL IN THE FUEL TANKS, LINES, CARBURETOR BOWL, AND ACCELERATOR PUMP. NO FUEL WAS FOUND IN THE GASCOLATOR. THE ENG WAS LATER TEST RUN AND OPERATED SATISFACTORILY. THE FUEL LINE BETWEEN THE FIREWALL AND CARBURETOR WAS SAID TO BE A RUBBER VACUUM LINE AND AN UNAPPROVED INSTALLATION. THE LINE WAS SO DETERIORATED AND BRITTLE THAT IT BROKE INTO SEVERAL PIECES WHILE BEING REMOVED FOR EXAMINATION. THE PLT REPORTED HE USED A STOPWATCH TO KEEP TRACK OF THE FUEL SUPPLY BECAUSE THE FUEL GAGES WERE INACCURATE.

## Aircraft

- Registration: [N2432D](https://openairdocs.org/deregistered/N2432D-2012-09-06), registration cancelled 2012-09-06, S/N 20584, built 1952 (OpenAirDocs)
- Reported make and model: CESSNA 170B
- Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs)
- Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 20584
- Airframe hours: 2980
- Engines: FRANKLIN O-300 165 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: David G. Jones
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, March 28, 1985, 50 hours before
- Departed: 8U4, SPOTTED BEAR, MT
- Airport: 8U4

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 23; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 104 total, 48 in this make and model, 76 as pilot in command, 48 in the last 90 days, 7 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 260° at 11 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 86 °F, dew point 41 °F
- Altimeter: 30.00 inHg
- Observed at: FCA, 40 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 19850706029729A](https://openairdocs.org/incident/19850706029729A), Jul 6, 1985: Cessna 170B, Swan Lake, MT, Substantial damage. Ran out of fuel 30 minutes after takeoff. Landed on creek bed, hit felled tree on rollout and overturned.

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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