# NTSB ANC91LA089: Cessna 170B, N3158A, Prospect Creek, AK, July 4, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 4, 1991, 13:30 local (21:30 UTC)
- Place: Prospect Creek, AK
- Coordinates: 64.809654, -147.719696 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=64.8097&lon=-147.7197&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report May 3, 1993
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5572
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC91LA089
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5572/pdf
- Page: https://openairdocs.org/ntsb/ANC91LA089

## Probable cause

CONTINUED VFR FLIGHT INTO INSTRUMENT METEOROLOGICAL CONDITIONS (IMC) BY THE PILOT, AND HIS DELAY IN REVERSING COURSE (REMEDIAL ACTION).  THE TERRAIN AND WEATHER CONDITIONS WERE RELATED FACTORS.

## Sequence of events

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

- In flight encounter with weather, cruise
  - terrain condition - high terrain (contributing factor)
  - weather condition - clouds (contributing factor)
  - weather condition - rain (contributing factor)
  - weather condition - low ceiling (contributing factor)
  - weather condition - fog (contributing factor)
  - vfr flight into imc - inadvertent, pilot in command (cause)
- In flight collision with object, maneuvering - turn to reverse direction
  - remedial action - delayed, pilot in command (cause)
  - terrain condition - rising (contributing factor)
  - airspeed - not possible, pilot in command
  - stall/mush - inadvertent, pilot in command
  - object - tree(s)

## Analysis

IN THE AREA OF A MOUNTAIN PASS, THE PILOT ENTERED CONDITIONS OF RAIN THAT QUICKLY TURNED TO CLOUDS AND INSTRUMENT CONDITIONS.  HE ATTEMPTED A 180 DEGREE TURN BACK TO VFR CONDITIONS, BUT ENCOUNTERED RISING TERRAIN WHILE FLYING ABOVE THE TREETOPS.  SUBSEQUENTLY, THE AIRCRAFT MUSHED INTO TREES AND CRASHED.

## Aircraft

- Registration: [N3158A](https://openairdocs.org/deregistered/N3158A-2014-10-09), registration cancelled 2014-10-09, S/N 25802, 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 C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 25400
- Engines: FRANKLIN 6A-350-C reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Daniel E. Wheeler
- Registered owner: Daniel E. Wheeler
- Airworthiness certificate: Standard, Normal
- Last inspection: Unknown, January 2, 2000
- Departed: FAI, FAIRBANKS, AK
- Destination: 1AK1, CREVICE CREEK, AK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 68; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 2,155 total, 1,519 in this make and model, 2,080 as pilot in command, 26 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Day
- Wind: calm

## 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 19910704026229A](https://openairdocs.org/incident/19910704026229A), Jul 4, 1991: Cessna 170B, Prospect Creek, AK, Substantial damage. Encountered rain,fog and clouds. Saw hole during 180. Descended into trees on rising terrain.

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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