# NTSB ANC13CA034: Piper PA-16, N5942H, Big Lake, AK, March 17, 2013 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: March 17, 2013, 12:30 local (20:30 UTC) - Place: Big Lake, AK - Coordinates: 61.466667, -150.399993 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.4667&lon=-150.4000&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report June 24, 2013 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration - NTSB case key (mKey): 86458 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC13CA034 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86458/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86458 - Page: https://openairdocs.org/ntsb/ANC13CA034 ## Probable cause The pilot's decision to land on unsuitable terrain. ## 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: [Piper PA-16, 2 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=7101602), [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 · Contributed to outcome; cases with it: [Piper PA-16, 1 case](https://openairdocs.org/ntsb-findings/03023015/cases.md?model=7101602), [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-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) (defining event); cases with it: [Piper PA-16, 6 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=7101602), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-16, 9 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7101602), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was landing his tailwheel-equipped airplane on a 1,400-foot-long, remote airstrip located on a frozen, snow-covered lake. According to the pilot, the surface of the airstrip appeared to be hard, compacted snow with a turn-around at its south end. Before beginning the approach, the pilot determined a touchdown point in the turn-around area to afford maximum use of the landing surface. After touchdown, the main wheels sank into the snow, and the airplane nosed over, which resulted in substantial damage to the rudder, lift struts, and wings. Upon exiting the airplane, the pilot realized that the turn-around area was loose, soft snow that had not been compacted. The pilot reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. ## Factual narrative The pilot was landing his tailwheel-equipped airplane at a 1,400-foot-long, remote airstrip located on a frozen snow-covered lake. The surface of the airstrip appeared to be hard compacted snow with a turn-around at the south end of the airstrip. Before beginning the approach he determined a touchdown point in the turn-around area to afford maximum use of the landing surface. After touchdown the main wheels sank into the soft snow, and the airplane nosed over resulting in substantial damage to the rudder, lift struts and wings. Upon exiting the airplane, the pilot realized that the turn-around area was loose soft snow that had not been compacted. The pilot indicated there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation. ## Aircraft - Registration: [N5942H](https://openairdocs.org/aircraft/N5942H), registered now, S/N 16-564, built 1949 (OpenAirDocs) - Reported make and model: PIPER PA-16 - Registry model: [Piper PA-16](https://openairdocs.org/model/piper-pa-16) (registry code 7101602) (OpenAirDocs) - Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 16-564 - Airframe hours: 3407 - Engines: LYCOMING O-235 SERIES 108 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Ylvisaker Robert G - Registered owner: Ylvisaker Robert G - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 20, 2012 - Departed: PAAQ, Palmer, AK - Destination: PVT, Big Lake, AK - Airport: PVT, Private, runway 18, 1,400 × 40 ft, snow ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 76; injuries: none; commercial; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review October 27, 2012; seat: left; flight hours: 3,908 total, 171 in this make and model, 3,751 as pilot in command, 2 in the last 90 days, 2 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 18 °F, dew point 1 °F - Altimeter: 30.13 inHg - Observed at: PAAQ, 36 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 20130317003249A](https://openairdocs.org/incident/20130317003249A), Mar 17, 2013: Piper PA-16, Big Lake, AK, Substantial damage. Pilot was attempting to land a wheel plane on an airstrip on a frozen lake that had a marked out landing area made of hard packed snow. The approach end had a… ## Other investigations on N5942H (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 SEA05CA148](https://openairdocs.org/ntsb/SEA05CA148), Jul 20, 2005: Piper PA-16 (N5942H), Park City, MT, substantial damage. Probable cause: The failure of the pilot to maintain directional control of the airplane on the takeoff roll. Factors contributing to the accident included the loose gravel, ditch, and the fence. - [NTSB SEA02LA102](https://openairdocs.org/ntsb/SEA02LA102), Jun 15, 2002: Piper PA-16 (N5942H), Umpqua, OR, substantial damage. Probable cause: The pilot's failure to adequately compensate for unfavorable wind conditions and maintain clearance from the terrain during an attempted VFR go-around. Factors include an encounter with unfavorable… ## Docket (1 files) The files NTSB released with the investigation on April 18, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86458. 3.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40389663&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.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.