# NTSB WPR21LA163: Piper PA-18-150, N83359, Wilsall, MT, April 18, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: April 18, 2021, 11:30 local (17:30 UTC) - Place: Wilsall, MT - Coordinates: 46.05, -110.685 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.0500&lon=-110.6850&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: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 102938 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA163 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102938/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102938 - Page: https://openairdocs.org/ntsb/WPR21LA163 ## Probable cause The pilot's failure to maintain directional control during the landing roll with a crosswind. ## 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-18-150, 160 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7101828), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Piper PA-18-150, 98 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=7101828), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Wind: crosswind](https://openairdocs.org/ntsb-findings/03034040): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Piper PA-18-150, 13 cases](https://openairdocs.org/ntsb-findings/03034040/cases.md?model=7101828), [All aircraft, 1,008 cases](https://openairdocs.org/ntsb-findings/03034040/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: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Piper PA-18-150, 109 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=7101828), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Piper PA-18-150, 18 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=7101828), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) ## Analysis The pilot of a tailwheel-equipped airplane reported that, while conducting a wheel landing on a grass runway with a direct crosswind, as the tailwheel settled onto the ground, the airplane veered right. He attempted to correct by applying left brake. Subsequently, the airplane ground looped to the right, substantially damaging the left wing and elevator when they impacted the ground. The pilot reported that there were no pre accident mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N83359](https://openairdocs.org/aircraft/N83359), registered now, S/N 18-7609099, built 1976 (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: 18-7609099 - Year built: 1976 - Airframe hours: 4560 - Engines: Lycoming O-320-B2B 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 11, 2020, 20 hours before - Destination: Same as departure - Airport: 9U1, Wilsall, runway 19, 3,100 × 78 ft, grass/turf - Equipment: Stall warning system, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review June 5, 2020; seat: front; restraint: 3-point; flight hours: 432 total, 66 in this make and model, 432 as pilot in command, 4 in the last 90 days, 3 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 10 knots - Temperature: 59 °F, dew point 25 °F - Altimeter: 30.11 inHg - Observed at: KBZM, 25 nm away - METAR: SA 18/04/2021 17:56-> METAR KBZN 181756Z VRB06KT 10SM CLR 15/M04 A3011 RMK AO2 SLP190 T01501044 10156 21050 58020= ## 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 20210418008469A](https://openairdocs.org/incident/20210418008469A), Apr 18, 2021: Piper PA-18-150, Wilsall, MT, Substantial damage. The pilot stated "in the landing configuration I entered a wing low approach with right aileron and left rudder. I was in perfect alignment with the runway and… ## Docket (2 files) The files NTSB released with the investigation on September 21, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102938. 2.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12596762&FileExtension=pdf&FileName=WPR21LA163%20Point%20One_Redacted-Rel.pdf - Photos (item 2, PDF, 2 pages, 2 photos, 621 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12638350&FileExtension=pdf&FileName=Photo%201-Rel.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.