# NTSB ANC16CA041: Piper PA18, N4231Z, Palmer, AK, June 27, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: June 27, 2016, 10:00 local (18:00 UTC) - Place: Palmer, AK - Coordinates: 61.438056, -148.66806 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.4381&lon=-148.6681&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report December 5, 2016 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration - NTSB case key (mKey): 93600 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC16CA041 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93600/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93600 - Page: https://openairdocs.org/ntsb/ANC16CA041 ## Probable cause The pilot's selection of unsuitable terrain for an off-airport landing, which resulted in a collision with trees and a ground-loop. ## 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: [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Decision related to condition (probable cause); cases with it: [All aircraft, 933 cases](https://openairdocs.org/ntsb-findings/03022020/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: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis The pilot was landing his tailwheel-equipped airplane on a rough and uneven, gravel covered, off-airport landing site adjacent to a river. Prior to landing, the pilot overflew the landing site multiple times at different altitudes for inspection. During the landing rollout the right wing struck tree branches, which resulted in a ground-loop. The airplane sustained substantial damage to the wings, empennage and left horizontal stabilizer. The pilot stated that there were no preaccident mechanical anomalies with the airplane that would have precluded normal operation. In the recommendation section of the NTSB Accident/Incident Reporting Form 6120.1, the pilot stated that the accident may have been prevented if he would have increased his familiarization of off-airport operations, or selected a more suitable landing site. ## Factual narrative The pilot was landing his tailwheel-equipped airplane on a rough and uneven, gravel covered, off-airport landing site adjacent to a river. Prior to landing, the pilot overflew the landing site multiple times at different altitudes for inspection. During the landing rollout the right wing struck tree branches, which resulted in a ground-loop. The airplane sustained substantial damage to the wings, empennage and left horizontal stabilizer. The pilot stated that there were no preaccident mechanical anomalies with the airplane that would have precluded normal operation. In the recommendation section of the NTSB Accident/Incident Reporting Form 6120.1, the pilot stated that the accident may have been prevented if he would have increased his familiarization of off-airport operations, or selected a more suitable landing site. ## Aircraft - Registration: N4231Z (not matched to a registry record) - Reported make and model: PIPER PA18 (A150) - Category: Airplane - Serial number: 18-8457 - Year built: 1966 - Airframe hours: 2897.4 - Engines: LYCOMING 0-320 SERIES 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 5, 2016 - Departed: PALH, Anchorage, AK - Destination: Palmer, AK - Equipment: Satellite tracking device, Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 26; injuries: none; commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; seat: front; restraint: 4-point; flight hours: 1,229 total, 128 in this make and model, 860 as pilot in command, 140 in the last 90 days, 24 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 12 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 45 °F - Altimeter: 30.14 inHg - Observed at: PAAQ, 17 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 20160627023639A](https://openairdocs.org/incident/20160627023639A), Jun 27, 2016: Piper PA-18-150, Palmer, AK, Substantial damage. The right wheel came in contact with unseen rise in gravel bar on landing roll out causing the aircraft to make a sudden right turn. The right wing tip struck… ## Docket (1 files) The files NTSB released with the investigation on October 25, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93600. 658 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 658 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40445665&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-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.