# NTSB WPR23LA102: Cessna 175, N9235B, Hayden, ID, January 31, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: January 31, 2023, 11:45 local (19:45 UTC) - Place: Hayden, ID · KCOE - Coordinates: 47.77, -116.82 - Nearby events: https://openairdocs.org/map.md?lat=47.7700&lon=-116.8200&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 106672 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA102 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106672/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106672 - Page: https://openairdocs.org/ntsb/WPR23LA102 ## Probable cause The failure of the right main landing gearbox assembly due to fatigue cracking, which resulted in a loss of directional control during the landing roll. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Cessna 175, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2072502), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/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: [Cessna 175, 7 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2072502), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/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: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Cessna 175, 3 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2072502), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Cessna 175, 6 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=2072502), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis The pilot receiving instruction and flight instructor reported that, during the landing roll, while slowing the airplane in preparation to exit the runway, the airplane abruptly turned to the right. Despite the application of left rudder and left brake, the airplane continued to the right and ground looped. The pilot taxied the airplane back to his hangar and noticed that the rudder inputs needed were not typical. Upon examination at his hangar, he discovered substantial damage to the left wing, left horizontal stabilizer and elevator. He also noted that the right main landing gear leg was misaligned, and the right main landing gearbox assembly was fractured. Postaccident examination of the right main landing gearbox revealed evidence of fatigue cracking within the hollow slot of the assembly and subsequent overstress fractures outside of the fatigue zone. ## Factual narrative On January 31, 2023, about 1145 Pacific standard time, a Cessna 175, N9235B, sustained substantial damage when it was involved in an accident near Hayden, Idaho. The pilot and flight instructor were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The pilot receiving instruction reported that, during the landing roll, he slowed the tailwheel-equipped airplane to exit the runway at taxiway B. Without warning, the airplane began an abrupt right turn. The pilot applied full left rudder and left brake; however, the airplane continued the right turn and ground looped. He did not see damage to the airplane and decided to taxi clear of the runway and back to his hangar. The flight instructor reported that, “...it seemed to take a significantly greater application to get the airplane moving, and the pilot seemed to have to use left rudder to taxi the airplane straight.” The pilot receiving instruction reported that, “...the controls were not behaving true.” After exiting the airplane, they discovered substantial damage to the left wing, left horizontal stabilizer, and left side of the elevator. The right main landing gear leg was misaligned, and the gearbox assembly was fractured. The right main landing gearbox assembly was removed and retained for further examination. Maintenance records showed that the most recent annual inspection was completed on 12/22/22. They also showed that the right main landing gear outboard saddle (part number 175-8) was repaired in September of 2019 and again in May of 2020. Postaccident examination and fracture analysis of the right main landing gearbox assembly was conducted by the National Transportation Safety Board Materials Laboratory. The examination revealed evidence of fatigue cracks within the hollow slot of the gearbox assembly. Outside the zone of the fatigue cracking, the fracture surfaces exhibited coarse features, typical of overstress. ## Aircraft - Registration: [N9235B](https://openairdocs.org/aircraft/N9235B), registered now, S/N 55035, built 1958 (OpenAirDocs) - Reported make and model: CESSNA 175 - Registry model: [Cessna 175](https://openairdocs.org/model/cessna-175) (registry code 2072502) (OpenAirDocs) - Registry engine: [Continental GO-300 series](https://openairdocs.org/engine/continental-go-300-series) (registry code 17024, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 55035 - Year built: 1958 - Airframe hours: 3980 - Engines: Lycoming O-360 A1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Van Winkle Christopher S - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 22, 2022 - Airport: COE, Coeur D'Alene/Pappy Boyington Field, runway 02, 5,400 × 75 ft, asphalt - Equipment: Auto-pilot, Electronic flight bag or handheld device, Electronic multifunction display, Electronic primary flight display, Onboard weather, Satellite tracking device, Stall warning system, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review October 19, 2021; seat: left; restraint: 4-point; flight hours: 141 total, 141 in this make and model, 26 as pilot in command - Flight instructor; age 69; injuries: none; airline transport, flight instructor, commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review October 26, 2022; seat: right; restraint: 4-point; flight hours: 8,520 total, 1 in this make and model, 4,187 as pilot in command, 20 in the last 90 days, 16 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 20° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: 6,500 ft broken - Temperature: 19 °F, dew point 10 °F - Altimeter: 30.22 inHg - Observed at: KCOE - METAR: KCOE 311756Z AUTO 02007KT 10SM BKN065 M07/M12 A3022 ## 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 20230131003559A](https://openairdocs.org/incident/20230131003559A), Jan 31, 2023: Cessna 175, Coeur D Alene, ID, Substantial damage. This accident involved a Cessna C175 operating under part 91. The flight was conducted as a currency flight for [privacy data omitted], a private pilot, flying… ## Other investigations on N9235B (1) 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. - [NTSB GAA19CA381](https://openairdocs.org/ntsb/GAA19CA381), Jul 1, 2019: Cessna 175 (N9235B), Coeur d'Alene, ID, substantial damage. Probable cause: The pilot's improper landing flare, which resulted in a bounced landing, and his subsequent failure to maintain directional control during landing with a gusting crosswind, which resulted in a… ## Docket (5 files) The files NTSB released with the investigation on July 5, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106672. 10.5 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16558901&FileExtension=pdf&FileName=WPR23LA102_6120_flat_pilot_owner_Redacted-Rel.pdf - Pilot/cfi aircraft accident report, NTSB form 6120.1 (item 2, PDF, 11 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16559084&FileExtension=pdf&FileName=WPR23LA102_6120_flat_flightinstructor_Redacted-Rel.pdf - Photo array (item 3, PDF, 3 pages, 944 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16559335&FileExtension=pdf&FileName=WPR23LA102_508-Rel.pdf - Maintenance records (item 4, PDF, 8 pages, 4.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17181077&FileExtension=pdf&FileName=2022%20annual%20inspection%20%26%20mlg%20record-Rel.pdf - Materials laboratory factual report 23-105 (item 5, PDF, 7 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16626663&FileExtension=pdf&FileName=23-105%20%20MLG%20gearbox-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.