# NTSB WPR20CA080: Merwin Kitfox, N399A, Goodyear, AZ, January 25, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Data collection · Final report - Date: January 25, 2020, 08:50 local (15:50 UTC) - Place: Goodyear, AZ - Coordinates: 33.423332, -112.375274 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.4233&lon=-112.3753&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: Federal Aviation Administration - NTSB case key (mKey): 100864 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR20CA080 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100864/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100864 - Page: https://openairdocs.org/ntsb/WPR20CA080 ## Probable cause The tail wheel mechanism detachment for reasons that could not be determined due to the lack of available evidence which resulted in the loss of directional control on landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause) - [Landing gear system: nose/tail gear attach section](https://openairdocs.org/ntsb-findings/01023221): Aircraft › Aircraft systems · Failure (probable cause) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause) ## Analysis The pilot of the tailwheel-equipped airplane reported that, he was on a familiarization/test flight with the pilot/owner. They had conducted 7 successful landings and while on final approach for the 8th landing, he entered a forward slip to steepen the descent angle without increasing airspeed, and pitched for landing. As the airplane touched down, there was no drift or yaw; however, during the landing rollout the rudder pedals "jerked," and the nose began to veer rapidly to the left. He applied right rudder pedal, but the airplane continued to yaw to the left and subsequently ground looped. The airplane sustained substantial damage to the rudder The pilot reported that the tailwheel chains and steering springs were intact, but the chains were not attached to the springs, and one of the tailwheel steering chains may have disconnected while maneuvering to land. The nut retaining the tailwheel spring was not located and the spring hole appeared to be undamaged. ## 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) ## Aircraft - Registration: [N399A](https://openairdocs.org/aircraft/N399A), registered now, S/N KA12273245, built 2019 (OpenAirDocs) - Reported make and model: MERWIN Kitfox (S7 Super S) - Registry model: [Jim Merwin KITFOX S7 SUPER SPOR](https://openairdocs.org/model/jim-merwin-kitfox-s7-super-spor) (registry code 05638CL) (OpenAirDocs) - Registry engine: [Rotax 912ULS series](https://openairdocs.org/engine/rotax-912uls-series) (registry code 55572, 4 cycle) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: KA12273245 - Year built: 2019 - Airframe hours: 6 - Engines: Rotax 912ULS 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental light sport (Special) - Departed: GYR, Goodyear, AZ - Destination: GYR, Goodyear, AZ - Airport: GYR, Phoenix Goodyear, runway 21, 8,500 × 150 ft, asphalt - Equipment: Satellite tracking device, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 71; injuries: none; flight instructor, airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review February 22, 2018; seat: right; restraint: 4-point; flight hours: 14,000 total, 5 in this make and model, 15 in the last 90 days - Pilot-rated passenger; age 76; injuries: none; private; airplane ratings: single-engine land; medical: basicmed; last flight review January 25, 2020; seat: left; restraint: 4-point; flight hours: 302 total, 6 in this make and model, 302 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 54 °F, dew point 43 °F - Altimeter: 30.09 inHg - Observed at: KGYR, 1 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 20200125002319A](https://openairdocs.org/incident/20200125002319A), Jan 25, 2020: Jim Merwin KITFOX S7 SUPER SPOR, Goodyear, AZ, Substantial damage. The pilot reported that the aircraft was being operated as experimental amateur-built during phase 1 flight testing to determine takeoff and landing… ## Docket (4 files) The files NTSB released with the investigation on October 9, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100864. 23.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 - flying pilot (item 1, PDF, 11 pages, 6.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10057713&FileExtension=pdf&FileName=N399A%20NTSB%20report_Redacted-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1 - pilot/owner (item 2, PDF, 10 pages, 16.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10057248&FileExtension=pdf&FileName=owner%206120_Redacted-Rel.pdf - FAA record of conversation (item 3, PDF, 1 page, 45 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10058515&FileExtension=pdf&FileName=LKelley%20ROC_Redacted-Rel.pdf - Photos (item 4, PDF, 3 pages, 369 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10058402&FileExtension=pdf&FileName=WPR20CA080%20Photographs-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.