# NTSB CEN13CA108: Piper PA-18-150, N3471Z, Okaton, SD, December 11, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: December 11, 2012, 09:00 local (15:00 UTC) - Place: Okaton, SD - Coordinates: 43.886112, -100.891944 - Nearby events: https://openairdocs.org/map.md?lat=43.8861&lon=-100.8919&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report April 3, 2013 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA - Rapid City FSDO - NTSB case key (mKey): 85841 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13CA108 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/85841/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=85841 - Page: https://openairdocs.org/ntsb/CEN13CA108 ## Probable cause The pilot's failure to perform an adequate preflight inspection of the airplane and obstruction of the aileron control system by snow and ice, which led to a loss of control during flight. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Piper PA-18-150, 4 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=7101828), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) - [Flight control system: aileron control system](https://openairdocs.org/ntsb-findings/01022710): Aircraft › Aircraft systems · Inadequate inspection (probable cause); cases with it: [Piper PA-18-150, 2 cases](https://openairdocs.org/ntsb-findings/01022710/cases.md?model=7101828), [All aircraft, 45 cases](https://openairdocs.org/ntsb-findings/01022710/cases.md) - [Temp/humidity/pressure: conducive to structural icing](https://openairdocs.org/ntsb-findings/03031025): Environmental issues › Conditions/weather/phenomena · Contributed to outcome (probable cause); cases with it: [Piper PA-18-150, 2 cases](https://openairdocs.org/ntsb-findings/03031025/cases.md?model=7101828), [All aircraft, 103 cases](https://openairdocs.org/ntsb-findings/03031025/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft inspection event](https://openairdocs.org/ntsb-events/050); cases with it: [Piper PA-18-150, 2 cases](https://openairdocs.org/ntsb-events/050/sequence.md?model=7101828), [All aircraft, 229 cases](https://openairdocs.org/ntsb-events/050/sequence.md) - [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Piper PA-18-150, 41 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7101828), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-18-150, 115 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7101828), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that 2 days before the accident, snow accumulated on the airplane’s wings while it was parked in an open front hangar. The day before the accident, the temperature was warmer, and the pilot believed that the snow melted and ran rearward to the aileron gap/hinge locations, re-freezing during the nighttime hours. On the day of the accident, the pilot was in a hurry to use the airplane to check his pastures and brushed the snow off of the wings but did not perform a thorough preflight check of the airplane, including checking freedom of movement of the ailerons. After takeoff, the airplane began turning to the left. The pilot attempted to correct the turn, but the airplane did not respond. When he looked out at the wings, he could see that the ailerons were not responding to control inputs as they should. As he was attempting to regain control, the airplane descended into trees, resulting in substantial damage to both wings, the fuselage, and tail surfaces. A postaccident examination of the airplane revealed no mechanical defects that were determined to have existed before the accident. ## Factual narrative The pilot reported that two days prior to the accident, snow accumulated on the wings of the airplane while it was in an open front hangar. The day prior to the accident the temperature was warmer and the pilot believed that the snow melted and ran rearward to the aileron gap/hinge locations, re-freezing during the nighttime hours. The day of the accident the pilot said he was in a hurry to use the airplane to check his pastures and brushed the snow off of the wings, but did not perform a thorough preflight check of the airplane and did not check freedom of movement of the ailerons. After takeoff, the airplane began turning to the left. The pilot said that he attempted to correct, but there was no response. When he looked out at the wings, he could see that the ailerons were not responding to control inputs as they should. As he was attempting to regain control, the airplane descended into trees. A postaccident examination of the airplane revealed no defects that were determined to have existed prior to the accident. The airplane sustained substantial damage to both wings, the fuselage and tail surfaces. ## Aircraft - Registration: [N3471Z](https://openairdocs.org/aircraft/N3471Z), registered now, S/N 18-7291, built 1960 (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: 18-7291 - Engines: LYCOMING O-320 SERIES 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Departed: PVT, Okaton, SD - Destination: PVT, Okaton, SD - Airport: PVT, Private airstrip, runway 09, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: front; flight hours: 2,000 total, 600 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 320° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 9,500 ft overcast - Temperature: 19 °F, dew point 16 °F - Altimeter: 29.85 inHg - Observed at: PHP, 37 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 20121211027059A](https://openairdocs.org/incident/20121211027059A), Dec 11, 2012: Piper PA-18-150, Okaton, SD, Substantial damage. Pilot stated that he had left the hanger doors open on Sunday, 12/08/12 and that a layer of snow approx. 8 inches thick had accumulated on the top of the wings… ## Other investigations on N3471Z (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 MKC72FTK29](https://openairdocs.org/ntsb/MKC72FTK29), May 23, 1972: Piper PA-18 (N3471Z), Fort Pierre, SD, substantial damage ## Docket (1 files) The files NTSB released with the investigation on January 16, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=85841. 102 KB in all. - Record of conversation with pilot (item 1, .PDF, 102 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40384777&FileExtension=.PDF&FileName=Record%20of%20conversation%20with%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.