# NTSB WPR23LA321: Cessna T210M, N6535B, Napa, CA, August 21, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: August 21, 2023, 12:10 local (19:10 UTC) - Place: Napa, CA - Coordinates: 38.214484, -122.28205 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.2145&lon=-122.2820&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 192922 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA321 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192922/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192922 - Page: https://openairdocs.org/ntsb/WPR23LA321 ## Probable cause Insufficient hydraulic pressure to the landing gear system following the completion of the emergency gear extension checklist, which resulted in the main landing gear collapsing during landing. Contributing to the accident was a loss of electrical power for reasons that could not be determined based on available evidence, which resulted in a failure of the normal landing gear extension system. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Electrical power system](https://openairdocs.org/ntsb-findings/01022400): Aircraft › Aircraft systems · Unknown/Not determined (probable cause); cases with it: [Cessna T210M, 1 case](https://openairdocs.org/ntsb-findings/01022400/cases.md?model=2073451), [All aircraft, 48 cases](https://openairdocs.org/ntsb-findings/01022400/cases.md) - [Landing gear system: gear position and warning](https://openairdocs.org/ntsb-findings/01023260): Aircraft › Aircraft systems · Inoperative (probable cause); cases with it: [Cessna T210M, 1 case](https://openairdocs.org/ntsb-findings/01023260/cases.md?model=2073451), [All aircraft, 37 cases](https://openairdocs.org/ntsb-findings/01023260/cases.md) - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Cessna T210M, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2073451), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible; cases with it: [Cessna T210M, 5 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=2073451), [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. - [Initial climb: Electrical system malf/failure](https://openairdocs.org/ntsb-events/332); cases with it: [Cessna T210M, 1 case](https://openairdocs.org/ntsb-events/332/sequence.md?model=2073451), [All aircraft, 182 cases](https://openairdocs.org/ntsb-events/332/sequence.md) - [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Cessna T210M, 7 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2073451), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Cessna T210M, 6 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=2073451), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot was flying the airplane to an airport where the annual inspection was to be performed. During climb out, the airplane sustained a total loss of electrical power. The pilot elected to return to the departure airport, and during the return, she was able to regain communication on one radio. The pilot followed the emergency landing gear extension checklist and attempted to manually apply hydraulic pressure to extend the landing gear. However, she could not verify that the landing gear was fully extended and locked due to the electrical failure. She reported that she pumped the manual handle up and down over 55 times (cycles) and felt the handle was stiff when she stopped pumping. The pilot flew a visual approach to land and, while on the base leg, tower personnel told her the gear appeared to be down. The pilot continued the approach, and during landing, both main landing gear collapsed, resulting in the airplane exiting the runway and striking a fence and brush. The owner of the airplane did not respond to investigator inquiries, and disposed of the airplane before an examination could be completed. As a result, the reason for the electrical failure that precipitated the landing gear collapse could not be determined. The Landing Gear Failure to Extend checklist directs the pilot to pump the emergency hand pump “until resistance becomes heavy - about 65 cycles,” and contains a note that indicated, “It takes about 55 cycles (110 strokes) to extend the gear.” The accident is consistent with the landing gear not extending normally following a loss of electrical power, and subsequently was not locked in the down position following completion of the emergency gear extension checklist. Although the pilot pumped the emergency gear extension handle the minimum recommended times, the pressure created was likely insufficient to ensure the landing gear were fully extended and locked in the down position, which resulted in the main landing gear collapsing during landing. ## Factual narrative On August 21, 2023, at 1210 Pacific daylight time, a Cessna T210, N6535B, was substantially damaged when it was involved in an accident near Napa, California. The pilot, pilot-rated passenger, and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulation Part 91 personal flight. According to the pilot, she was repositioning the airplane to Modesto, California, to undergo an annual inspection. After takeoff from Napa County Airport (APC), Napa, California, while climbing to about 3,500 ft mean sea level (msl) the airplane sustained a total electrical failure. The pilot elected to return to APC. Before landing, the landing gear would not extend normally when commanded due to the loss of electrical power, so the pilot performed a manual gear extension. She said she followed the pilot operating handbook (POH) emergency procedures and pumped the manual gear extension lever up and down more than 55 times (cycles) and felt significant resistance. Partial electrical power was restored to one radio and the pilot was able to communicate with air traffic control. She flew a visual approach to runway 19R, and during the turn to the base leg of the airport traffic pattern the tower controller told her that the gear appeared to be down. The pilot continued to the runway and, during landing, both main landing gear collapsed, resulting in the airplane skidding off the right side of the runway, striking brush, and substantially damaging the right wing and right horizontal stabilizer. The POH states that gear extension and retraction, wheel well door operation, and up and down lock operation is accomplished by hydraulic actuators powered by an electrically driven hydraulic power pack. The power pack assembly is housed within the control pedestal. Power pack operation is initiated by a landing gear lever and is turned off by a pressure switch. Two-position indicator lights are provided to show landing gear position. The landing gear system is also equipped with a nose gear safety switch, an emergency extension hand pump, and a gear­up warning system. The Landing Gear Fails to Extend checklist directs the pilot to pump the emergency hand pump “until resistance becomes heavy - about 65 cycles,” and contains the note “It takes about 55 cycles (110 strokes) to extend the gear (light on) and about 10 more (until resistance becomes heavy) to close the gear doors.” The airplane owner did not respond to requests for investigators to examine the wreckage. He did not submit the National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report Form 6120.1or produce the airplane’s logbooks. The owner disposed of the airplane before an examination could be completed. As a result, the electrical and landing gear systems were not examined. ## Aircraft - Registration: [N6535B](https://openairdocs.org/deregistered/N6535B-2023-11-17), registration cancelled 2023-11-17, S/N 21062783, built 1978 (OpenAirDocs) - Reported make and model: CESSNA T210M - Registry model: [Cessna T210M](https://openairdocs.org/model/cessna-t210m) (registry code 2073451) (OpenAirDocs) - Registry engine: [Continental TSIO-520 series](https://openairdocs.org/engine/continental-tsio-520-series) (registry code 17040, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 21062783 - Year built: 1978 - Engines: Continental TSIO-520 reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Destination: Modesto, CA - Airport: APC, Napa County Airport, runway 19R, 5,930 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 19; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review May 10, 2023; seat: left; restraint: 3-point; flight hours: 417 total, 1 in this make and model, 263 as pilot in command, 42 in the last 90 days, 36 in the last 30 days, 0 in the last 24 hours - Pilot-rated passenger; age 79; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; seat: right ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 11 knots - Visibility: 10 statute miles - Temperature: 77 °F, dew point 60 °F - Altimeter: 29.96 inHg - METAR: 11:53 AM 77 °F 60 °F 56 % SSW 13 mph 0 mph 29.96 in 0.0 in Mostly Cloudy ## 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 20230821016739A](https://openairdocs.org/incident/20230821016739A), Aug 21, 2023: Cessna T210M, Napa, CA, Substantial damage. On August 21st, 2023, at approximately 12:00PM PDT, the pilot was operating a Cessna T210M, on a relocation flight with [privacy data omitted]on board. The… ## Docket (7 files) The files NTSB released with the investigation on February 20, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192922. 4.9 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17525758&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Pilot email statement (item 2, PDF, 2 pages, 128 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17525942&FileExtension=pdf&FileName=Pilot%20Email%20Statement_Redacted-Rel.pdf - Memo for record - pilot statement clarification (item 3, PDF, 1 page, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18295137&FileExtension=pdf&FileName=MFR%20-%20Pilot%20Clarification%20of%20Statement-Rel.pdf - FAA narrative of events (item 4, PDF, 2 pages, 78 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17525768&FileExtension=pdf&FileName=FAA%20Narrative-Rel.pdf - POH extracts (item 5, PDF, 8 pages, 438 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17526185&FileExtension=pdf&FileName=POH_Extracts-Rel.pdf - Mor - owner contact attempts (item 6, PDF, 1 page, 95 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17526879&FileExtension=pdf&FileName=MOR%20-%20Owner%20Contact%20Attempts_Redacted-Rel.pdf - Photos (item 7, PDF, 4 pages, 3 photos, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17527373&FileExtension=pdf&FileName=Photos%20WPR23LA321-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.