# NTSB ANC25LA030: Cessna A185F, N1718R, Skwentna, AK, March 7, 2025 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: March 7, 2025, 14:00 local (23:00 UTC) - Place: Skwentna, AK · Highline Lake - Coordinates: 61.76501, -151.57764 - Nearby events: https://openairdocs.org/map.md?lat=61.7650&lon=-151.5776&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report March 4, 2026 - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 199961 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC25LA030 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/199961/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=199961 - Page: https://openairdocs.org/ntsb/ANC25LA030 ## Probable cause Maintenance personnel’s reuse of worn hardware during the installation of the landing gear assembly and the hardware’s failure and subsequent separation of the gear leg from the landing gear box assembly during taxi. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: repair](https://openairdocs.org/ntsb-findings/02062015): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna A185F, 1 case](https://openairdocs.org/ntsb-findings/02062015/cases.md?model=2072821), [All aircraft, 99 cases](https://openairdocs.org/ntsb-findings/02062015/cases.md) - [Landing gear system: main landing gear attach sec](https://openairdocs.org/ntsb-findings/01023211): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Cessna A185F, 2 cases](https://openairdocs.org/ntsb-findings/01023211/cases.md?model=2072821), [All aircraft, 66 cases](https://openairdocs.org/ntsb-findings/01023211/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Taxi: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Cessna A185F, 10 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=2072821), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) ## Analysis The pilot reported that, while taxiing for takeoff from a remote, snow-covered lake, the right landing gear leg collapsed, resulting in substantial damage to the landing gear box assembly and door post assembly. A postaccident examination of the right landing gear leg assembly revealed that the gear leg separated from its position in the landing gear box assembly and folded under the airplane. The bolt that secured the gear leg to the landing gear box assembly remained in place; however, the nut was found in the belly of the airplane. Although the hardware installed on the airplane’s main landing gear spring differed from the hardware specified in the airplane manufacturer’s parts catalog, the composition and hardness of the installed bolt were consistent with typical specifications for an AN-type bolt. However, the bolt and nut exhibited worn threads consistent with progressive wear over time rather than a sudden overload. The mechanic who performed a landing gear change about a year and a half before the accident stated that, although he did not recall the hardware used during the gear change, when he changes landing gear, he uses the hardware provided by the owner for installing the landing gear. Based on the condition of the nut and bolt, the worn hardware was likely re-used during the installation of the landing gear assembly. Re-use of the worn bolt and nut then allowed the hardware to fail under load during taxi, resulting in collapse of the landing gear. ## Factual narrative On March 7, 2025, about 1400 Alaska standard time, a ski-equipped Cessna 185 airplane, N1718R, sustained substantial damage when it was involved in an accident near Skwentna, Alaska. The pilot and two passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane was taxiing for takeoff from a remote snow-covered lake when the right landing gear leg collapsed, resulting in substantial damage to the landing gear box assembly and door post assembly. According to maintenance records, the airplane had flown about 83 hours between May 2023 and the time of the accident. The owner reported that in October 2023, floats and float rigging were removed from the airplane and the main landing gear and wheels were installed. A review of the maintenance records did not reveal this alteration. Further review of the maintenance records indicated the wheels were removed in December 2023 and skis were installed on the airplane’s main landing gear legs. The mechanic who performed the landing gear change in October 2023 stated that, although he did not recall the hardware used during the landing gear change, when he changes landing gear he uses the hardware provided by the owner for installing the gear. When asked why there was no entry made in the maintenance logbook for the landing gear assembly change, he said the owner never provided the logbooks for him to sign. The hardware found installed on the airplane’s main landing gear spring was an AN7-20 bolt with a cross-drilled hole through the threaded portion of the bolt and an MS20365-720A nylon locking nut. According to the Cessna 180 and 185 Parts Catalog the hardware at the inboard end of the main landing gear spring should have consisted of an AN7-20A bolt that does not have a cross-drilled hole and an MS20365-70C nut, which is a locking nut with an all-metal design, and a spring adjustment shim. The hardware was submitted to the NTSB’s Materials Laboratory for examination. The examination indicated that the bolt exhibited patchy and faint remnants of cadmium plating on the flats of the head. The shank of the bolt did not exhibit any remaining cadmium plating. The composition and hardness of the bolt were consistent with typical specifications for an AN-type bolt. The nut had worn and patchy cadmium plating. Both the bolt and nut exhibited worn threads. The worn threads near the end of the bolt contained bits of the nut’s nylon locking insert. The nylon locking insert was worn down to the depth of the worn threads inside the nut; the wear was consistent with the thread wear occurring over time and not from a sudden instance of overload. ## Aircraft - Registration: [N1718R](https://openairdocs.org/aircraft/N1718R), registered now, S/N 18502439, built 1974 (OpenAirDocs) - Reported make and model: CESSNA A185F - Registry model: [Cessna A185F](https://openairdocs.org/model/cessna-a185f) (registry code 2072821) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18502439 - Year built: 1974 - Airframe hours: 4302 - Engines: Continental IO-520-D-24 285 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 3, 2024, 36 hours before - Destination: LHD, Anchorage, AK - Airport: None - Equipment: Handheld GPS, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; injuries: none; private; airplane ratings: single-engine sea, single-engine land; medical: class 3, without waivers/limitations; last flight review April 6, 2025; seat: left; restraint: 3-point; flight hours: 2,081 total, 545 in this make and model, 2,040 as pilot in command, 10 in the last 90 days, 3 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 10 knots - Visibility: 10 statute miles - Temperature: 20 °F - Observed at: PASW, 16 nm away - METAR: PASWskyc1,skyc2,skyc3,skyc4,skyl1,skyl2,skyl3,skyl4,wxcodes,peak_wind_gust,peak_wind_drct,peak_wind_time,feel,metar,snowdepth ## 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 20250307002559A](https://openairdocs.org/incident/20250307002559A), Mar 7, 2025: Cessna A185F, Skwentna, AK, Substantial damage. The accident pilot stated he was operating the aircraft from a frozen lake near his cabin located a few miles west of Skwentna, AK on March 7th, 2025. The area… ## Docket (5 files) The files NTSB released with the investigation on March 4, 2026, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=199961. 24.5 MB in all. - Materials laboratory factual report 25-044 (item 1, PDF, 7 pages, 5 photos, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18904198&FileExtension=pdf&FileName=Materials%20Lab%20Factual%20Report%20-%2025-044-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 2, PDF, 9 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18590139&FileExtension=pdf&FileName=ANC25LA030%206120_Redacted-Rel.pdf - Maintenance records (item 3, PDF, 3 pages, 20.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18590149&FileExtension=pdf&FileName=Last%202%20Annuals_Redacted-Rel.pdf - Memorandum of record-mechanic (item 4, PDF, 1 page, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18984248&FileExtension=pdf&FileName=MOR%20mechanic%20regarding%20float%20removal-Rel.pdf - Photos (item 5, PDF, 6 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18983957&FileExtension=pdf&FileName=Investigative%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.