# NTSB ERA25LA091: Helio HT-295, N18JC, Marion, OH, January 5, 2025 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: January 5, 2025, 17:00 local (22:00 UTC) - Place: Marion, OH · RWY 31 - Coordinates: 40.617135, -83.060953 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.6171&lon=-83.0610&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 199510 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA25LA091 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/199510/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=199510 - Page: https://openairdocs.org/ntsb/ERA25LA091 ## Probable cause The failure of the right main landing gear spring due to intergranular stress-corrosion cracking that progressed into fatigue. Contributing to the accident was the improper rework of the spring at an undetermined time. ## 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 · Fatigue/wear/corrosion (probable cause); cases with it: [Helio HT-295, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=4300803), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md) - [Maintenance: modification/alteration](https://openairdocs.org/ntsb-findings/02062030): Personnel issues › Task performance · Not specified (probable cause); cases with it: [Helio HT-295, 1 case](https://openairdocs.org/ntsb-findings/02062030/cases.md?model=4300803), [All aircraft, 69 cases](https://openairdocs.org/ntsb-findings/02062030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Helio HT-295, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=4300803), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Helio HT-295, 2 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=4300803), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot reported that, after a normal landing, the pilot heard a “pop” followed by a leaning tendency to the right that he attempted to correct with flight control inputs. He could not arrest the right turn, and the airplane departed the right side of the runway and came to a stop, upright, in the grass. The right wing and right stabilator sustained substantial damage. The right main landing gear spring separated during the landing roll. Metallurgical examination of the spring revealed evidence of chloride intergranular stress-corrosion cracking that progressed into fatigue over time. The examination also found evidence of the spring being reworked after manufacture, with grinding marks perpendicular to the lengthwise direction of the part (contrary to manufacturer-approved procedures), areas of missing paint, and corrosion pitting. The operator reported that the spring had not been removed or reworked since they purchased the airplane more than 25 years before the accident. ## Factual narrative On January 5, 2025, about 1700 eastern standard time, a Helio HT-295 airplane, N18JC, was substantially damaged when it was involved in an accident near Marion, Ohio. The commercial pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 positioning flight. The pilot reported that he was en route from Buffalo Niagara International Airport (BUF), Buffalo, New York, to Coleman A. Young Municipal Airport (DET), Detroit, Michigan, when he elected to divert to Marion Municipal Airport (MNN), Marion, Ohio, due to deteriorating weather conditions. He prepared for a visual straight-in approach to runway 31. After a normal landing, the pilot heard a “pop” followed by a leaning tendency to the right that he attempted to correct with flight control inputs. He could not arrest the right turn, and the airplane departed the right side of the runway and came to a stop, upright, in the grass. He secured the airplane, and he was met by first responders. FAA inspectors responded to the accident site and examined the wreckage. The left wing and left stabilator sustained substantial damage. The right main landing gear spring separated at the fuselage connection point. The inspectors removed the spring section that remained inside the fuselage and secured the outboard section of the spring. The fractured gear spring parts were sent to the NTSB Materials Laboratory for further examination. The examination revealed that the spring fractured at the upper, inboard end of the spring between the inboard attachment hole and the outboard support bracket. The fracture was located about 4.5-4.75 inches away from the inboard end of the spring. The examination revealed evidence of chloride intergranular stress-corrosion cracking. After the crack grew over time, the dominant fracture mechanism turned to fatigue. Beyond the fatigue boundary, the fracture area showed evidence of ductile overstress failure. The gear spring was found to be consistent with Cessna part number 0741001-8 main landing gear spring, reportedly used on the Helio HT-295. The leg also showed indications of rework after manufacture. The corners of the leg had chamfers with variable width and geometry. The chamfer surface had grinding marks that were perpendicular (traverse) to the lengthwise direction of the leg. There were also areas of missing paint and corrosion pitting. According to Cessna Specification CSPS026, grinding of the main landing gear spring in the longitudinal direction is permitted; however, no transverse grinding is permitted on either edges or flats. The operator reported that there were no aircraft logbook entries showing removal or reworking of the main landing gear since they purchase it in September 1998. ## Aircraft - Registration: [N18JC](https://openairdocs.org/aircraft/N18JC), registered now, S/N 1719, built 1974 (OpenAirDocs) - Reported make and model: HELIO HT-295 - Registry model: [Helio HT-295](https://openairdocs.org/model/helio-ht-295) (registry code 4300803) (OpenAirDocs) - Registry engine: [Lycoming GO-480 series](https://openairdocs.org/engine/lycoming-go-480-series) (registry code 41527, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1719 - Year built: 1974 - Airframe hours: 13933 - Engines: LYCOMING GO-480-G1A6 295 horsepower reciprocating - Damage: Substantial damage - Flight: Positioning, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 25, 2024, 227 hours before - Departed: DET, Detroit, MI - Destination: BUF, Buffalo, NY - Airport: MNN, Marion Municipal, runway 31, 3,498 × 100 ft, asphalt - Equipment: Handheld GPS, Onboard weather, ADS-B, Electronic flight bag or handheld device, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 26; injuries: none; commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review September 6, 2023; seat: left; restraint: 3-point; flight hours: 733 total, 233 in this make and model, 607 as pilot in command, 166 in the last 90 days, 56 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 10° at 18 knots, gusting 28 - Visibility: 9 statute miles - Lowest ceiling: 1,700 ft overcast - Temperature: 25 °F, dew point 18 °F - Altimeter: 29.98 inHg - Observed at: MNN - METAR: KMNN 062153Z AUTO 01018G28KT 9SM OVC017 M04/M08 A2998 RMK AO2 PK WND 02031/2104 SLP170 T10441078 ## Docket (5 files) The files NTSB released with the investigation on May 6, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=199510. 8.5 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18469312&FileExtension=pdf&FileName=6120.1_Redacted-Rel.pdf - NTSB memorandum for record - maintenance history (item 2, PDF, 1 page, 61 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18503003&FileExtension=pdf&FileName=2%20NTSB%20MOR%20-%20Maintenance%20History-Rel.pdf - Investigation photographs (item 3, PDF, 4 pages, 809 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18469388&FileExtension=pdf&FileName=Investigation%20Photographs-Rel.pdf - Materials laboratory factual report 25-012 (item 4, PDF, 17 pages, 22 photos, 5.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18468191&FileExtension=pdf&FileName=25-012-Rel.pdf - NTSB mor - Cessna service specification CSPS026 (item 5, PDF, 1 page, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18541496&FileExtension=pdf&FileName=2c%20NTSB%20MOR%20-%20CESSNA%20SPECIFICATION%20CSPS026-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.