# NTSB WPR21LA328: Piper PA-18-150, N89ZW, Wasilla, AK, August 20, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: August 19, 2021, 18:55 local (Aug 20, 2021, 02:55 UTC) - Place: Wasilla, AK - Coordinates: 61.639324, -149.2854 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.6393&lon=-149.2854&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi-from runway: Prop/jet/rotor blast/suction](https://openairdocs.org/ntsb-events/082) - Highest injury: No injuries - Injuries: 1 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): 103757 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA328 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103757/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103757 - Page: https://openairdocs.org/ntsb/WPR21LA328 ## Probable cause The pilot’s inability to maintain control of the airplane during taxi after it encountered the prop wash from a larger airplane that was conducting a high-power engine run on the same taxiway. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Capability exceeded (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) - [Object/animal/substance: aircraft](https://openairdocs.org/ntsb-findings/03022040): Environmental issues › Physical environment · Ability to respond/compensate (probable cause); cases with it: [Piper PA-18-150, 2 cases](https://openairdocs.org/ntsb-findings/03022040/cases.md?model=7101828), [All aircraft, 116 cases](https://openairdocs.org/ntsb-findings/03022040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Taxi-from runway: Prop/jet/rotor blast/suction](https://openairdocs.org/ntsb-events/082) (defining event); cases with it: [Piper PA-18-150, 1 case](https://openairdocs.org/ntsb-events/082/sequence.md?model=7101828), [All aircraft, 44 cases](https://openairdocs.org/ntsb-events/082/sequence.md) ## Analysis The pilot reported that, after landing he taxied back up the runway to the north. As he reached the end of the runway, and approached the most northerly taxiway, he had to maneuver around another airplane that was parked partially in the taxiway easement and on the runway. As he began to make a right turn onto the taxiway, the airplane was blown sideways about 15-20 ft as a result of the wind from the operating propellers (prop-wash) from a turbo-prop airplane performing a full engine run at a maintenance hangar. The pilot stated that his airplane was dropped onto its left wing and subsequently was spun to the south. Despite the pilot’s attempt of using full brakes to keep the airplane in place, the airplane slid backward and was temporary lifted airborne before it collided with the ground. As a result of the impact, the airplane sustained substantial damage to the left rear spar and aileron. The pilot reported that there were no preimpact mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N89ZW](https://openairdocs.org/aircraft/N89ZW), registered now, S/N 18-7509114, built 1975 (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 IO-320 series](https://openairdocs.org/engine/lycoming-io-320-series) (registry code 41509, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-7509114 - Year built: 1975 - Airframe hours: 3147 - Engines: Lycoming O-320-A2B 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 2, 2021, 50 hours before - Departed: 88AK, Sterling, AK - Destination: Same as departure - Airport: 4AK6, Wolf Lake, runway 18/36, 2,600 × 100 ft, gravel - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; private; airplane ratings: single-engine sea, single-engine land; medical: class 3, with waivers/limitations; last flight review October 7, 2020; seat: front; restraint: 3-point; flight hours: 879 total, 879 in this make and model, 855 as pilot in command, 33 in the last 90 days, 10 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: 10,000 ft - Temperature: 60 °F, dew point 47 °F - Altimeter: 29.98 inHg - Observed at: PAAQ, 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 20210819013849A](https://openairdocs.org/incident/20210819013849A), Aug 19, 2021: Piper PA-18-150, Palmer, AK, Substantial damage. 08/26/2021: Aircraft was empty PA-18 landing on rwy 18 at 4AK6. When crossing threshold at ~20' AGL, aircraft encountered severe crosswind from the left… ## Docket (2 files) The files NTSB released with the investigation on December 9, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103757. 3.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12904456&FileExtension=pdf&FileName=Z%20-%20Attachment%2001%20-%206120%20master_Redacted-Rel.pdf - Photographs (provided by the pilot) (item 2, PDF, 4 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12904466&FileExtension=pdf&FileName=Z-%20Attachment%2002%20-Photos-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.