# NTSB ANC83LA063: Cessna 170B, N1955C, North Pole, AK, March 31, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 31, 1983, 16:30 local (20:30 UTC)
- Place: North Pole, AK
- Coordinates: 64.769691, -147.330673 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=64.7697&lon=-147.3307&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 4110
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC83LA063
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/4110/pdf
- Page: https://openairdocs.org/ntsb/ANC83LA063

## Sequence of events

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

- Loss of control - on ground/water, landing - roll
  - landing gear,ski assembly - improper (contributing factor)
  - maintenance,installation - improper (contributing factor)
  - landing gear,ski assembly - worn (cause)
  - directional control - not possible, pilot in command
- On ground/water collision with object, landing - roll
  - object - aircraft parked/standing (contributing factor)
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - snowbank (contributing factor)

## Analysis

THE PLT OF THE SKI EQUIPPED ACFT HAD TAKEN OFF FROM AN ABANDONDED STRIP THAT WAS IN A DETERIORATING CONDITION WITH ROCKS SCATTERED ALONG THE LANDING AREA. AFTER ARRIVING AT HIS DESTINATION, HE LANDED ON A WELL GRADED RWY WITH PACKED SNOW THAT WAS SUITABLE FOR EITHER WHEEL OR SKI OPERATION. AFTER TOUCHDOWN, THE ACFT BEGAN TO VEER TO THE LEFT. SUBSEQUENTLY, IT WENT OFF THE LEFT SIDE OF THE RWY & THE LEFT WING OF THE ACFT HIT THE LEFT WING OF A PIPER PA-12, N3140M. AFTER THAT, THE ACFT CONTINUED UNTIL IT STRUCK A SNOWBANK, THEN TRAVELED ABOUT 50 FT FURTHER BEFORE COMING TO REST. AN EXAM OF THE GEAR REVEALED THAT THE LEFT SKI WAS WORN. THE OVERLAYER WAS SCRAPED AWAY & APRX AN 18 INCH, OUTBOARD PORTION WAS BENT INWARD. THERE WAS EVIDENCE THAT THE SKI HAD HIT THE SNOWBANK WHILE THE LEFT WING WAS LOW CAUSING A TRANSVERSE FRACTURE & FAILURE OF THE LEFT AXLE (A NON-STANDARD C-185 AXLE). IMPROPER BOLTS HAD BEEN USED TO INSTALL THE NON-STANDARD AXLES & NO SHIMS HAD BEEN USED TO PROVIDE PROPER AXLE ALIGNMENT.

## Aircraft

- Registration: [N1955C](https://openairdocs.org/aircraft/N1955C), registered now, S/N 26100, 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: 26100
- Airframe hours: 3500
- Engines: LYCOMING IO-360-B 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Keith W. Mitchell
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 1, 1982
- Departed: CHICKEN, AK
- Airport: Lakloey, runway 24, 4,000 × 90 ft, snow

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 1,170 total, 1,170 in this make and model, 1,150 as pilot in command, 50 in the last 90 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 10 knots
- Visibility: 80 statute miles
- Lowest ceiling: none
- Temperature: 36 °F, dew point 16 °F
- Altimeter: 29.00 inHg

## 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 19830331012509A](https://openairdocs.org/incident/19830331012509A), Mar 31, 1983: Cessna 170B, North Pole, AK, Substantial damage. Swerved off the runway into a parked aircraft and a snowbank on landing. Prior ski damage. Rocky departure airport.

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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