# NTSB ANC17LA016: Piper PA18, N1268A, Sterling, AK, February 9, 2017 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: February 8, 2017, 15:03 local (Feb 9, 2017, 00:03 UTC) - Place: Sterling, AK - Coordinates: 60.510276, -150.850555 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=60.5103&lon=-150.8506&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report November 15, 2018 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 94703 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC17LA016 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/94703/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=94703 - Page: https://openairdocs.org/ntsb/ANC17LA016 ## Probable cause The pilot’s loss of control while maneuvering for reasons that could not be determined based on the available information. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Piper PA-18-125, 2 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7101812), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: lateral/bank control](https://openairdocs.org/ntsb-findings/01062023): Aircraft › Aircraft oper/perf/capability · Not specified (probable cause); cases with it: [Piper PA-18-125, 1 case](https://openairdocs.org/ntsb-findings/01062023/cases.md?model=7101812), [All aircraft, 390 cases](https://openairdocs.org/ntsb-findings/01062023/cases.md) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not specified (probable cause); cases with it: [Piper PA-18-125, 1 case](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=7101812), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Piper PA-18-125, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=7101812), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220); cases with it: [Piper PA-18-125, 1 case](https://openairdocs.org/ntsb-events/220/sequence.md?model=7101812), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Maneuvering-low-alt flying: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Piper PA-18-125, 1 case](https://openairdocs.org/ntsb-events/000/sequence.md?model=7101812), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) - [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Piper PA-18-125, 2 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7101812), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering-low-alt flying: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-18-125, 2 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7101812), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The private pilot reported that, while making a right turn during a personal flight, the flight controls "stuck." She was unable to make aileron or elevator control inputs, and was also unable to correct the airplane's bank using rudder inputs. The airplane subsequently descended in a right turn until it impacted the ground. The airplane was removed from the accident site before it could be examined. During recovery, both wings and their control cables were cut. The airplane was later examined on the pilot's property, strapped to a trailer. Examination of the airframe and engine revealed no evidence of any control anomalies that would have precluded normal operation; however, since the flight control system was compromised during the recovery, the pre-accident condition of the flight controls could not be determined and the investigation was unable to establish a reason for the pilot's reported loss of control. ## Factual narrative On February 8, 2017, about 1503 Alaska standard time (AST), a ski-equipped Piper PA-18-125 airplane, N1268A, sustained substantial damage when it impacted terrain while maneuvering about 4 miles southwest of Sterling, Alaska. The private pilot sustained serious injuries. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed for the personal flight, which originated from the pilot's private airstrip about 3 miles southwest of Sterling about 1445. An Alaska State Trooper who responded to the site just after the accident stated that, when he arrived, the pilot told him the airplane became uncontrollable when the aileron control system locked in place as she turned the airplane to the right. Unable to roll the wings level, the airplane subsequently descended nose low and struck the surface of a frozen river. The pilot added she was unable to make aileron or elevator control inputs and was unable to "correct" by using rudder inputs. A Garmin Aera 500 GPS was recovered from the airplane and downloaded by an NTSB Investigator. The accident flight was recorded starting at 12:18:31 AST on February 8, 2017. Refer to the GPS Factual Report in the public docket for further flight track information. Family members of the pilot removed the wreckage from the accident site without permission of the NTSB and before an on-scene examination was performed. Photographs taken the day of the accident showed that the airplane impacted an area of snow-and ice-covered terrain on a river. The airplane came to rest in a near-vertical, nose-down attitude. The right wing exhibited spanwise twisting and was displaced about 30° aft of the airplane's lateral axis. The left wing displayed impact damage on the forward inboard section and wingtip and separation from the fuselage at the rear spar attachment points, and was displaced about 60° forward of the airplane's lateral axis. The propeller remained attached to the engine and exhibited aft bending and torsional twisting of both blades. The airplane was examined on the pilot's property on February 9 strapped to a trailer with several of its components separated and placed inside the airplane cabin. Both wings and the landing gear were removed, and the control cables for both wings were cut during the recovery operation. Control continuity was established for the rudder and elevator control systems. The aileron cables displayed continuity except for a right wing through-cable pulley, which was no longer located on the pulley track but was wedged between the pulley and attachment hardware. The pulley was sent to the NTSB Materials Laboratory for further examination; no evidence of unusual wear in the pulley or cable and no slack or loose connections in the pulley system was found. ## Aircraft - Registration: [N1268A](https://openairdocs.org/aircraft/N1268A), registered now, S/N 18-1063, built 1951 (OpenAirDocs) - Reported make and model: PIPER PA18 (125) - Registry model: [Piper PA-18-125](https://openairdocs.org/model/piper-pa-18-125) (registry code 7101812) (OpenAirDocs) - Registry engine: [Lycoming 0-290 series](https://openairdocs.org/engine/lycoming-0-290-series) (registry code 41506, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 18-1063 - Year built: 1951 - Airframe hours: 3535 - Engines: LYCOMING O-320 SERIES 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 13, 2017 - Departed: Sterling, AK - Destination: Sterling, AK - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 27; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: front; restraint: 4-point; flight hours: 292 total, 262 as pilot in command, 15 in the last 90 days, 10 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 2,300 ft overcast - Temperature: 25 °F, dew point 10 °F - Altimeter: 29.84 inHg - Observed at: PASX, 6 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 20170208007499A](https://openairdocs.org/incident/20170208007499A), Feb 8, 2017: Piper PA-18-125, Soldotna, AK, Substantial damage. Statement from pilot- Pilot departed private airstrip at 1435 and flew towards kenai river and made a right hand turn. At this time the pilot reported that she… ## Docket (8 files) The files NTSB released with the investigation on September 13, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=94703. 4.3 MB in all. - Materials Laboratory (item 1, .PDF, 31 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466649&FileExtension=.PDF&FileName=Materials%20Laboratory-Master.PDF - GPS Factual Report (item 2, .PDF, 860 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466650&FileExtension=.PDF&FileName=GPS%20Factual%20Report-Master.PDF - GPS Factual Report - Attachment 1 (item 3, .PDF, 562 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466651&FileExtension=.PDF&FileName=GPS%20Factual%20Report%20-%20Attachment%201-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 4, .PDF, 854 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466652&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Memorandum for Record – Telephone Interview, Pilot (item 5, .PDF, 230 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466653&FileExtension=.PDF&FileName=Memorandum%20for%20Record%20%E2%80%93%20Telephone%20Interview,%20Pilot-Master.PDF - Memorandum for Record – Pilot's Spouse (item 6, .PDF, 275 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466654&FileExtension=.PDF&FileName=Memorandum%20for%20Record%20%E2%80%93%20Pilot%27s%20Spouse-Master.PDF - Wreckage Release (item 7, .PDF, 32 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466655&FileExtension=.PDF&FileName=Wreckage%20Release-Master.PDF - Accident Pictures (item 8, .PDF, 5 photos, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466656&FileExtension=.PDF&FileName=Accident%20Pictures-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.