# NTSB DEN89LA065: Piper PA-18-150, N83596, Medicine Lake, MT, January 19, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: January 19, 1989, 10:30 local (17:30 UTC)
- Place: Medicine Lake, MT
- Coordinates: 48.50053, -104.370109 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=48.5005&lon=-104.3701&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report January 31, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 17665
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN89LA065
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17665/pdf
- Page: https://openairdocs.org/ntsb/DEN89LA065

## Probable cause

SELECTION OF UNSUITABLE TERRAIN BY THE PILOT, RESULTING IN A COLLISION WITH SNOWDRIFTS DURING LANDING GROUND RUN.

## Sequence of events

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

- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - snowbank (contributing factor)
  - unsuitable terrain or takeoff/landing/taxi area - selected, pilot in command (cause)
- Nose down, landing - roll

## Analysis

THE COMMERCIAL PLT AND A FRIEND LANDED IN A SNOW COVERED FIELD DURING A PERSONAL TRANSPORTATION FLT. THE LEFT SKI STRUCK COMPACTED SNOW DRIFTS AND THE LEFT AXLE BROKE. WITH THE LEFT SKI GONE, THE LANDING GEAR DUG INTO THE SNOW AND THE ACFT NOSED DOWN.

## Aircraft

- Registration: [N83596](https://openairdocs.org/aircraft/N83596), registered now, S/N 18-7709096, built 1977 (OpenAirDocs)
- Reported make and model: PIPER PA-18-150
- Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 18-7709096
- Airframe hours: 2017
- Engines: LYCOMING O-320-A2B 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Carlson Aerial, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, March 16, 1988, 94 hours before
- Departed: PWD, PLENTYWOOD, MT
- Destination: NONE, BAINEVILLE, MT

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: rear; flight hours: 5,000 total, 1,200 in this make and model, 4,900 as pilot in command, 100 in the last 90 days, 30 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 15 knots, gusting 20
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 10 °F
- Altimeter: 30.00 inHg

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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