# NTSB WPR23LA012: Cessna T210L, N2425S, Marana, AZ, October 10, 2022 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: October 10, 2022, 16:45 local (23:45 UTC) - Place: Marana, AZ · departed runway surface into an open field - Coordinates: 32.409556, -111.21838 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.4096&lon=-111.2184&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 106125 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA012 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106125/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106125 - Page: https://openairdocs.org/ntsb/WPR23LA012 ## Probable cause A failure of a retaining ring in the airplane’s left main landing gear door actuator and the subsequent complete loss of hydraulic fluid, which resulted in a gear-up landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: landing gear actuator](https://openairdocs.org/ntsb-findings/01023233): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Cessna T210L, 2 cases](https://openairdocs.org/ntsb-findings/01023233/cases.md?model=2073449), [All aircraft, 54 cases](https://openairdocs.org/ntsb-findings/01023233/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Cessna T210L, 6 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2073449), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis During a post-maintenance test flight after an engine overhaul and annual airframe inspection, the pilot retracted the landing gear as he departed the runway. While on the downwind leg of the airport traffic pattern the pilot lowered the landing gear handle, but the landing gear remained retracted and stowed and the associated green indicator light was not illuminated. The pilot attempted to troubleshoot the anomaly and eventually performed an emergency landing. The airplane touched down on the partially extended nose landing gear and fuselage, resulting in damage to the left horizontal stabilizer and elevator. Postaccident examination of the landing gear system revealed that the left main landing gear actuator retaining ring separated from the actuator cylinder, exposing the internal rod and O-rings. The separation exposed a hole in the cylinder and a loss of hydraulic fluid followed, leaving the system unpressurized. The lack of system pressure resulted in the failure of the nose landing gear door actuator assembly and the subsequent gear-up landing. The retaining ring inside the actuator cannot be visibly inspected due to the position of the seat being recessed into the cylinder. The actuator does not have a specified overhaul time or cycle limit. ## Factual narrative On October 10, 2022, about 1645 mountain standard time, a Cessna T210L, N2425S, sustained substantial damage when it was involved in an accident near Marana, Arizona. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that this was the airplane’s first flight after an engine overhaul and airframe annual inspection. The pilot reported that he planned a maintenance test flight, and after a normal takeoff, he retracted the landing gear. Shortly after, while on the downwind leg of the airport traffic pattern, he noticed that the landing gear position indicator light was not illuminated. The pilot cycled the landing gear control lever, but the position indicator lights remained unchanged and did not illuminate. Using the mirrors affixed to the airframe, the pilot was able to verify that the nose landing gear appeared extended, and the left main gear door was open but appeared abnormal. The pilot subsequently used the emergency hand pump to extend the landing gear but felt no resistance or hydraulic pressure develop when the pump was actuated. The pilot then made a low pass over the runway and ground personnel confirmed that the nose landing gear was extended; however, the left and right main landing gear were not. The pilot remained airborne about 50 minutes to burn off fuel before landing. He performed a stable approach and touched down before the airplane exited the left side of the runway. The airplane sustained substantial damage to the left horizontal stabilizer and elevator. Postaccident examination of the landing gear system revealed that the left main landing gear actuator retaining ring separated from the actuator cylinder, exposing the internal rod and O-rings. It is not possible to inspect the retaining ring inside the actuator due to the position of the seat being recessed into the cylinder. The actuator currently does not have a specified overhaul time or cycle limit. ## Aircraft - Registration: [N2425S](https://openairdocs.org/aircraft/N2425S), registered now, S/N 21061276, built 1976 (OpenAirDocs) - Reported make and model: CESSNA T210L - Registry model: [Cessna T210L](https://openairdocs.org/model/cessna-t210l) (registry code 2073449) (OpenAirDocs) - Registry engine: [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series) (registry code 17040, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 21061276 - Year built: 1976 - Airframe hours: 2891 - Engines: Continental TSIO-520H 285 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 9, 2022, 1 hours before - Destination: Same as departure - Airport: AVQ, Marana Rgnl, runway 03, 3,892 × 75 ft, asphalt - Equipment: Electronic flight bag or handheld device, Auto-pilot, ADS-B, Electronic primary flight display, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 68; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: basicmed, with waivers/limitations; last flight review September 8, 2022; seat: left; restraint: 3-point; flight hours: 1,611 total, 1,308 in this make and model, 1,456 as pilot in command, 2 in the last 90 days, 2 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 10 knots - Visibility: 10 statute miles - Temperature: 81 °F, dew point 48 °F - Altimeter: 29.90 inHg - Observed at: KRYN, 16 nm away - METAR: KRYN 102345Z 20010KT 10SM SCT095 27/09 A2990 ## Docket (5 files) The files NTSB released with the investigation on May 2, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106125. 11.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 8.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16509894&FileExtension=pdf&FileName=6120_1_Redacted-Rel.pdf - Memorandum for record_IA statements (item 2, PDF, 2 pages, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16509756&FileExtension=pdf&FileName=Memorandum%20for%20Record-Rel.pdf - Landing gear door actuator schematic (item 3, PDF, 4 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16509500&FileExtension=pdf&FileName=Nose%20Landing%20Gear%20Door%20Actuator%20Schematic-Rel.pdf - FAA material defect report (item 4, PDF, 2 pages, 435 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16508697&FileExtension=pdf&FileName=FAA%20Form%208010-4_Material%20Defect%20Report-Rel.pdf - Photographs (item 5, PDF, 4 pages, 645 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16585811&FileExtension=pdf&FileName=Photographs-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.