# NTSB WPR19LA169: Cessna 140, N73053, Independence, OR, June 12, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: June 12, 2019, 14:15 local (21:15 UTC) - Place: Independence, OR - Coordinates: 44.867221, -123.19833 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.8672&lon=-123.1983&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): 99607 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR19LA169 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99607/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99607 - Page: https://openairdocs.org/ntsb/WPR19LA169 ## Probable cause Fatigue failure of the right landing gear axle, which resulted in a loss of control during the landing roll. ## 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 · Attain/maintain not possible (probable cause); cases with it: [Cessna 140, 27 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2071602), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Landing gear system: main gear strut/axle/truck](https://openairdocs.org/ntsb-findings/01023213): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna 140, 2 cases](https://openairdocs.org/ntsb-findings/01023213/cases.md?model=2071602), [All aircraft, 86 cases](https://openairdocs.org/ntsb-findings/01023213/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: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Cessna 140, 3 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=2071602), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Cessna 140, 5 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2071602), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis According to the instructor, the accident landing was the second landing of the flight. As the tailwheel-equipped airplane was slowing down and they were exiting the runway, there was a loud "clunk." The airplane slid sideways, bounced, and then ground looped, resulting in substantial damage to the fuselage. The instructor reported that the right wheel assembly separated at the axle. Examination of the fractured axle assembly revealed that the axle fractured at the transition radius between the longitudinal barrel (tube) portion and the plate portion. A fatigue crack emanated from multiple origins at the outer surface of the transition radius and extended circumferentially around the outer surface of the transition radius. The fracture features outside of the fatigue region showed features consistent with overstress separation. The maintenance history of the landing gear and axle could not be determined. The fatigue crack started at the transition radius most likely as the result of a hard landing or several hard landings. Once the fatigue crack started, the crack propagated during taxiing and additional takeoffs and landings. ## Factual narrative On June 12, 2019, about 1435 Pacific daylight time, a Cessna 140 airplane, N73053, sustained substantial damage when it was involved in an accident near Independence, Oregon. The flight instructor and student pilot were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the instructor, the accident landing was the second landing of the flight. As the airplane was slowing down and they were exiting the runway, there was a loud "clunk." The airplane slid sideways, bounced, and then ground looped, resulting in substantial damage to the fuselage. The instructor reported that the right wheel assembly separated at the axle. The student pilot, who was the owner of the airplane, reported that he had purchased the airplane in April 2019 and was flying 1 to 3 times a week while working toward his private pilot certificate. During the previous flights, there had been no issues. Examination of the fractured axle assembly revealed that the axle fractured at the transition radius between the longitudinal barrel (tube) portion and the plate portion. A fatigue crack emanated from multiple origins at the outer surface of the transition radius and extended circumferentially around the outer surface of the transition radius. The fracture features outside of the fatigue region showed features consistent with overstress separation. The maintenance history of the landing gear and axle could not be determined. ## Aircraft - Registration: [N73053](https://openairdocs.org/deregistered/N73053-2022-01-12), registration cancelled 2022-01-12, S/N 10265, built 1946 (OpenAirDocs) - Reported make and model: Cessna 140 (Undesignat) - Registry model: [Cessna 140](https://openairdocs.org/model/cessna-140) (registry code 2071602) (OpenAirDocs) - Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 10265 - Year built: 1946 - Airframe hours: 5494.9 - Engines: Lycoming O-235-C1 115 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, August 7, 2018, 33.6 hours before - Departed: ONP, Newport, OR - Destination: Same as departure - Airport: 7S5, Independence State, runway 34, 3,142 × 60 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 57; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review September 22, 2017; seat: right; restraint: 4-point; flight hours: 1,879 total, 25 in this make and model, 1,860 as pilot in command, 302 in the last 90 days, 68 in the last 30 days, 3 in the last 24 hours - Student pilot; age 57; injuries: none; student; medical: class 3, with waivers/limitations; seat: left; restraint: 4-point; flight hours: 24 total, 24 in this make and model, 24 in the last 90 days, 11 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 91 °F, dew point 57 °F - Altimeter: 29.86 inHg - Observed at: KSLE, 9 nm away - METAR: METAR KSLE 122056Z 10SM CLR 33/14 A2986 RMK AO2 SLP110 T03330139 58014= ## 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 20190612006719A](https://openairdocs.org/incident/20190612006719A), Jun 12, 2019: Cessna 140, Independence, OR, Substantial damage. On Wednesday, June 12, 2019, a Cessna 140, registered as N73053, was involved in an accident at Independence state airport (7S5) in Independence, Oregon. The… ## Docket (6 files) The files NTSB released with the investigation on June 15, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99607. 4.8 MB in all. - Materials laboratoryfactual report 19-086 (item 1, PDF, 3 pages, 675 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=9038117&FileExtension=pdf&FileName=19-086%20-%20landing%20gear%20axle-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1 (student pilot) (item 2, PDF, 9 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13870545&FileExtension=pdf&FileName=WPR19LA169%20SHeinrich%206120_Redacted-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1 (flight instructor) (item 3, PDF, 9 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13870829&FileExtension=pdf&FileName=MShort%206120%20WPR19LA169_Redacted-Rel.pdf - Safo 10007 - tundra tire installation/approval for airplanes equipped with leaf spring type main landing gear (item 4, PDF, 2 pages, 44 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13870765&FileExtension=pdf&FileName=SAFO10007%20-%20axle%20failures-Rel.pdf - Evidence control form (item 5, PDF, 1 page, 28 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13869960&FileExtension=pdf&FileName=Evidence%20Control%20Form_Redacted-Rel.pdf - Photos (item 6, PDF, 2 pages, 984 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13869978&FileExtension=pdf&FileName=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.