# NTSB ANC21LA029: Cessna 170A, N1291D, Lime Village, AK, April 7, 2021

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: April 7, 2021, 10:00 local (18:00 UTC)
- Place: Lime Village, AK
- Coordinates: 61.170239, -154.82187 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=61.1702&lon=-154.8219&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Alaska Regional Office
- Parties: FAA
- NTSB case key (mKey): 102922
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC21LA029
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102922/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102922
- Page: https://openairdocs.org/ntsb/ANC21LA029

## Probable cause

The pilot’s selection of unsuitable terrain for landing, which resulted in a landing gear collapse.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 170A, 3 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2072304), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md)
- [Light condition: flat light](https://openairdocs.org/ntsb-findings/03036025): Environmental issues › Conditions/weather/phenomena · Effect on personnel; cases with it: [Cessna 170A, 1 case](https://openairdocs.org/ntsb-findings/03036025/cases.md?model=2072304), [All aircraft, 42 cases](https://openairdocs.org/ntsb-findings/03036025/cases.md)
- [Terrain: sloped/uneven terrain](https://openairdocs.org/ntsb-findings/03021017): Environmental issues › Physical environment · Effect on operation; cases with it: [Cessna 170A, 1 case](https://openairdocs.org/ntsb-findings/03021017/cases.md?model=2072304), [All aircraft, 270 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md)
- [Runway/land/takeoff/taxi surface: snow/slush/ice covered surface](https://openairdocs.org/ntsb-findings/03023015): Environmental issues › Physical environment · Effect on equipment; cases with it: [Cessna 170A, 2 cases](https://openairdocs.org/ntsb-findings/03023015/cases.md?model=2072304), [All aircraft, 219 cases](https://openairdocs.org/ntsb-findings/03023015/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Cessna 170A, 33 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=2072304), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md)
- [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Cessna 170A, 11 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2072304), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md)
- [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Cessna 170A, 14 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2072304), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

The pilot reported that, while landing off-airport on snow-covered terrain, in flat light conditions, the terrain was “rougher” than he expected. Subsequently, during the landing roll, the airplane encountered a “bump”, the right ski penetrated the surface of the snow, and the right main landing gear collapsed. The airplane sustained substantial damage to the right wing and fuselage. The pilot reported no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

## Aircraft

- Registration: [N1291D](https://openairdocs.org/deregistered/N1291D-2024-06-29), registration cancelled 2024-06-29, S/N 19867, built 1951 (OpenAirDocs)
- Reported make and model: CESSNA 170A
- Registry model: [Cessna 170A](https://openairdocs.org/model/cessna-170a) (registry code 2072304) (OpenAirDocs)
- Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 19867
- Year built: 1951
- Airframe hours: 1180.1
- Engines: CONT MOTOR O-300 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: David A. Hensel
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, July 6, 2020
- Departed: Big Lake, AK
- Destination: Stoney River, AK
- Equipment: Handheld GPS

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; injuries: none; private; airplane ratings: single-engine land; medical: class 1; last flight review January 22, 2020; seat: left; flight hours: 608.7 total, 531.1 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: 6,000 ft overcast
- Temperature: 18 °F, dew point 14 °F
- Altimeter: 30.04 inHg
- Observed at: PASV, 22 nm away
- METAR: PASV 071755Z AUTO 00000KT 10SM -SHSN OVC026 M08/M10 A3004 RMK AO2 SHSNB1626 SLP210 P0000 60000 T10831097 11079 21089 57020

## 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 20210407004919A](https://openairdocs.org/incident/20210407004919A), Apr 7, 2021: Cessna 170A, Lime Village, AK, Substantial damage. During normal off field snow landing Attempt in an location, 21 NM East south east of Lime Village (61.10.12.9N/154.49.18.8W), the right main landing gear and…

## Docket (3 files)

The files NTSB released with the investigation on August 20, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102922. 824 KB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 668 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12212535&FileExtension=pdf&FileName=6120-Rel.pdf
- Additional information (item 2, PDF, 1 page, 40 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12211837&FileExtension=pdf&FileName=Additional%20Information_Redacted-Rel.pdf
- Accident pictures (item 3, PDF, 2 pages, 117 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12211959&FileExtension=pdf&FileName=Accident%20pictures-Rel.pdf

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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