# NTSB ANC90LA043: Cessna 170B, N4659C, Sulatna Cross, AK, March 17, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 16, 1990, 20:00 local (Mar 17, 1990, 00:00 UTC)
- Place: Sulatna Cross, AK
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report December 15, 1992
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5344
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC90LA043
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5344/pdf
- Page: https://openairdocs.org/ntsb/ANC90LA043

## Probable cause

THE PILOT FAILED TO ADEQUATELY ASSESS THE EXISTING SNOW CONDITIONS AND SURROUNDING TERRAIN (PREFLIGHT PLANNING) PRIOR TO TAKEOFF.  CONTRIBUTING FACTORS WERE: THE LIGHTING CONDITIONS, THE PILOT'S OVER CONFIDENCE IN THE AIRPLANE'S PERFORMANCE CAPABILITIES AND THE SNOW COVERED TERRAIN.

## Sequence of events

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

- In flight collision with object, takeoff - initial climb
  - light condition - dusk (contributing factor)
  - terrain condition - snow covered (contributing factor)
  - preflight planning/preparation - inadequate, pilot in command (cause)
  - overconfidence in aircraft's ability, pilot in command (contributing factor)

## Analysis

THE PILOT STATED THAT HE WAS ATTEMPTING TO TAKE OFF FROM A FROZEN LAKE AT DUSK. LOOSE SNOW ON THE SURFACE OF THE LAKE ADVERSELY AFFECTED THE AIRPLANE'S TAKEOFF DISTANCE. THE PILOT SAID THAT SHORTLY AFTER LIFT OFF, THE AIRPLANE'S HORIZONTAL STABILIZER STRUCK A TREE, AND THAT HE MADE AN IMMEDIATE EMERGENCY LANDING. THE PILOT SAID THAT THE ACCIDENT COULD HAVE BEEN AVOIDED IF HE HAD WAITED FOR BETTER LIGHTING CONDITIONS, OR IF HE WOULD HAVE ABORTED THE TAKEOFF EARLY IN THE TAKEOFF ROLL.

## Aircraft

- Registration: [N4659C](https://openairdocs.org/aircraft/N4659C), registered now, S/N 25603, 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: 25603
- Engines: LYCOMING O-360-A1A 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Wilbur M. Smith
- Departed: MCG, MCGRATH, AK
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; flight hours: 2,800 total, 600 in this make and model, 2,800 as pilot in command

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: calm
- Visibility: 20 statute miles
- Lowest ceiling: 10,000 ft broken
- Temperature: 25 °F, dew point -0 °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 19900316008549A](https://openairdocs.org/incident/19900316008549A), Mar 16, 1990: Cessna 170B, Sulatna Cross, AK, Substantial damage. Tried to depart from strip with loose snow,in poor light. A ski hit soft snow, slowed and took off. Hit a tree.

## Other investigations on N4659C (2)

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 ANC01LA065](https://openairdocs.org/ntsb/ANC01LA065), Jun 4, 2001: Cessna 170B (N4659C), Sand Point, AK, substantial damage. Probable cause: The pilot's inadequate compensation for wind conditions while on approach, and the inadvertent stall of the airplane while attempting a go-around. A factor associated with the accident was a…
- [NTSB ANC91LA083](https://openairdocs.org/ntsb/ANC91LA083), Jun 30, 1991: Cessna 170B (N4659C), Lake Louise, AK, substantial damage. Probable cause: THE PILOT NOT MAINTAINING DIRECTIONAL CONTROL DURING THE TAKEOFF ROLL. CONTRIBUTING TO THE ACCIDENT WAS THE ROUGH CONDITION OF THE AIRSTRIP.

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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