# NTSB ANC24LA036: Cessna 190, N1500D, San Luis Obispo, CA, May 17, 2024 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: May 17, 2024, 15:00 local (22:00 UTC) - Place: San Luis Obispo, CA - Coordinates: 35.237273, -120.6426 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.2373&lon=-120.6426&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 3 - NTSB office: Alaska Regional Office - Parties: FAA - San Jose FSDO - NTSB case key (mKey): 194301 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC24LA036 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194301/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=194301 - Page: https://openairdocs.org/ntsb/ANC24LA036 ## Probable cause The pilot’s failure to maintain directional control during the landing roll, which resulted in a failure of the right main landing gear and subsequent ground loop. ## 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: [Cessna 190, 5 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072902), [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: [Cessna 190, 5 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2072902), [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: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Cessna 190, 5 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=2072902), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis The pilot reported that, during the landing roll, the airplane’s right main gear began to track under the fuselage. As the airplane slowed, he was unable to keep the aircraft under directional control. The airplane then ground-looped, substantially damaging the right wing. Metallurgical examination revealed the attachment bolts for the right main landing gear failed in downward and slightly aft bending. The two lower bolts fractured in overstress. The upper bolt was bent, and the nut was stripped. A side load on the right main landing gear wheel would have placed the axle in downward bending and drag forces during landing and roll out would have resulted in an aft loading component. The damage signatures observed were consistent with separation of the axle from the landing gear spring as a result of a ground loop. ## Factual narrative On May 17, 2024, about 1500 Pacific daylight time, a Cessna 190 airplane, N1500D, was substantially damaged when it was involved in an accident near San Luis Obispo, California. The pilot was uninjured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, during the landing roll on runway 29 at San Luis Obispo County Regional Airport (SBP), San Luis Obispo, the airplane’s right main gear began to track under the fuselage. As the airplane slowed, he was unable to maintain directional control, which resulted in a ground loop, substantially damaging the right wing. Following the accident, the pilot examined the airplane’s right main landing gear and found the bolts attaching the axle to the main gear spring had fractured. The fractured bolt allowed the right main wheel assembly to separate from the right main landing gear spring. The right main landing gear axle, tapered shim, and attachment bolt were collected and submitted to the National Transportation Safety Board’s Materials Laboratory in Washington, DC, for examination. The two fractured lower bolt shafts were retained in the axle. The tapered shim was bent and buckled outboard, downward, and slightly aft. Two curved witness marks were observed near the lower edge of the tapered shim. These witness marks were aligned with the hole features on the mating axle collar surface. The fractured bolt shafts retained in the axle exhibited a relatively rough, matte gray fracture surface morphology. Radial features were observed emanating from a thread root at the upper edge of both bolts over a relatively flat fracture surface through approximately 40% of the bolt cross section, at which point the fracture continued downward along an outboard and slightly aft slanted plane through the remainder of the bolt. The relatively flat fracture surface at the top of the bolt was consistent with overstress fracture from a downward bending load before the final fracture in downward and slightly aft bending.? ## Aircraft - Registration: [N1500D](https://openairdocs.org/aircraft/N1500D), registered now, S/N 7722, built 1951 (OpenAirDocs) - Reported make and model: CESSNA 190 - Registry model: [Cessna 190](https://openairdocs.org/model/cessna-190) (registry code 2072902) (OpenAirDocs) - Registry engine: [Continental W670 series](https://openairdocs.org/engine/continental-w670-series) (registry code 17018, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 7722 - Year built: 1951 - Airframe hours: 2616.2 - Engines: Jacobs L6-MB 330 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, November 5, 2023, 11.2 hours before - Departed: TSP, Tehachapi, CA - Destination: Same as departure - Airport: SBP, San Luis Obispo, runway 29, 6,101 × 100 ft, asphalt - Equipment: Electronic multifunction display, Electronic flight bag or handheld device, ADS-B, Stall warning system, Onboard weather, Electronic primary flight display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: none; flight instructor, commercial, airline transport; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review September 11, 2023; seat: left; restraint: lap only; flight hours: 33,000 total, 530 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 240° at 9 knots - Visibility: 10 statute miles - Temperature: 68 °F, dew point 52 °F - Altimeter: 29.95 inHg - Observed at: KSBP - METAR: KSBP 172156Z 24009KT 10SM FEW025 20/11 A2995 RMK AO2 SLP139 T02000111 ## 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 20240517006999A](https://openairdocs.org/incident/20240517006999A), May 17, 2024: Cessna 190, San Luis Obispo, CA, Substantial damage. On landing at the San Luis Obispo county airport, after touching down approximately 1000 feet down the runway, the aircraft tracked straight for approximately… ## Other investigations on N1500D (2) 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 MKC69D0316](https://openairdocs.org/ntsb/MKC69D0316), Jan 11, 1969: Cessna 190 (N1500D), Osage, IA, substantial damage - [NTSB MKC69F0309](https://openairdocs.org/ntsb/MKC69F0309), Jul 28, 1968: Cessna 190 (N1500D), Osage, IA, substantial damage ## Docket (3 files) The files NTSB released with the investigation on August 20, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=194301. 5.6 MB in all. - Materials laboratory factual report 25-034 (item 1, PDF, 7 pages, 6 photos, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18693533&FileExtension=pdf&FileName=25-034__Materials%20Laboratory%20Factual%20Report%20(ANC24LA036)-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 2, PDF, 11 pages, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18743093&FileExtension=pdf&FileName=6120%20V2_Redacted-Rel.pdf - Photos (item 3, PDF, 4 pages, 793 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18743113&FileExtension=pdf&FileName=ANC24LA036%20Photo%20Array-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.