# NTSB GAA18CA136: Cessna 180, N2934A, Big Lake, AK, February 17, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: February 17, 2018, 12:30 local (20:30 UTC) - Place: Big Lake, AK - Coordinates: 61.580001, -150.410003 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.5800&lon=-150.4100&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 14, 2018 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 96775 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA18CA136 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96775/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96775 - Page: https://openairdocs.org/ntsb/GAA18CA136 ## Probable cause The pilot’s selection of unsuitable terrain for landing, which led to both skis breaking through the ice while positioning the airplane after landing. ## 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 180, 16 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2072602), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Runway/land/takeoff/taxi surface: snow/slush/ice covered surface](https://openairdocs.org/ntsb-findings/03023015): Environmental issues › Physical environment · Decision related to condition (probable cause); cases with it: [Cessna 180, 5 cases](https://openairdocs.org/ntsb-findings/03023015/cases.md?model=2072602), [All aircraft, 219 cases](https://openairdocs.org/ntsb-findings/03023015/cases.md) - [Runway/land/takeoff/taxi surface: snow/slush/ice covered surface](https://openairdocs.org/ntsb-findings/03023015): Environmental issues › Physical environment · Effect on operation; cases with it: [Cessna 180, 5 cases](https://openairdocs.org/ntsb-findings/03023015/cases.md?model=2072602), [All aircraft, 219 cases](https://openairdocs.org/ntsb-findings/03023015/cases.md) - [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot; cases with it: [Cessna 180, 5 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=2072602), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Taxi: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) (defining event); cases with it: [Cessna 180, 7 cases](https://openairdocs.org/ntsb-events/900/sequence.md?model=2072602), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) ## Analysis The pilot reported that, after landing on a snow-covered, off-airport landing site, he was positioning the airplane for parking. He added that the left ski broke through the ice, followed by the right ski. He reported that he had not seen the area of "soft/thin" ice before taxiing. The airplane sustained substantial damage to the fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Factual narrative The pilot reported that, after landing on a snow covered, off airport landing site, he was repositioning the airplane for parking. He added that the left ski broke through the ice, followed by the right ski. He reported that he had not seen the area of "soft/thin" ice before taxiing. The airplane sustained substantial damage to the fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N2934A](https://openairdocs.org/aircraft/N2934A), registered now, S/N 30134, built 1953 (OpenAirDocs) - Reported make and model: CESSNA 180 (UNDESIGNAT) - Registry model: [Cessna 180](https://openairdocs.org/model/cessna-180) (registry code 2072602) (OpenAirDocs) - Registry engine: [Continental O-470 series](https://openairdocs.org/engine/continental-o-470-series) (registry code 17026, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 30134 - Year built: 1953 - Airframe hours: 3078.6 - Engines: CONT MOTOR O-470-A 225 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 12, 2017 - Departed: LHD, ANCHORAGE, AK - Destination: Big Lake, AK - Equipment: Electronic flight bag or handheld device, Electronic multifunction display, Handheld GPS, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; commercial; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review July 12, 2017; seat: left; restraint: 4-point; flight hours: 5,344 total, 2,172 in this make and model, 5,258 as pilot in command, 11 in the last 90 days, 4 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 40° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: 20,000 ft broken - Temperature: 16 °F, dew point 10 °F - Altimeter: 30.73 inHg - Observed at: PANC, 27 nm away ## 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 20180217003529A](https://openairdocs.org/incident/20180217003529A), Feb 17, 2018: Cessna 180, Big Lake, AK, Substantial damage. Pilot was taxing on frozen river, broke through ice when taxing to park. No injuries to pilot and passenger. ## Other investigations on N2934A (1) 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 ANC76DAG25](https://openairdocs.org/ntsb/ANC76DAG25), Aug 24, 1975: Cessna 180 (N2934A), Hook Creek, AK, substantial damage ## Docket (2 files) The files NTSB released with the investigation on April 5, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96775. 555 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 389 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461707&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Photo (Courtesy of Pilot) (item 2, .PDF, 1 photo, 166 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461708&FileExtension=.PDF&FileName=Accident%20Photo%20(Courtesy%20of%20Pilot)-Master.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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.