# Hydraulic fluid - Type: NTSB finding subsection - Path: [Aircraft](https://openairdocs.org/ntsb-findings/01) › [Fluids/misc hardware](https://openairdocs.org/ntsb-findings/0107) › [Fluids](https://openairdocs.org/ntsb-findings/010710) › Hydraulic fluid - NTSB code: 01071015 - Cases: 33 - In the probable cause: 28 - Fatal cases: 1 - All cases: https://openairdocs.org/ntsb-findings/01071015/cases.md - Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/01071015/cases.md?cause=1 - Page: https://openairdocs.org/ntsb-findings/01071015 ## Cases per year (in the probable cause / all) - 2008: 2 / 3 - 2009: 2 / 2 - 2010: 2 / 3 - 2011: 1 / 2 - 2012: 1 / 2 - 2013: 3 / 3 - 2015: 1 / 1 - 2016: 2 / 2 - 2018: 5 / 5 - 2019: 1 / 1 - 2020: 3 / 3 - 2021: 0 / 1 - 2022: 2 / 2 - 2023: 1 / 1 - 2025: 2 / 2 ## Defining events in these cases - [Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330): 19 cases - [Landing gear collapse](https://openairdocs.org/ntsb-events/094): 7 cases - [Loss of control on ground](https://openairdocs.org/ntsb-events/230): 2 cases - [Loss of control in flight](https://openairdocs.org/ntsb-events/240): 1 cases - [Ground collision](https://openairdocs.org/ntsb-events/200): 1 cases - [Fire/smoke (non-impact)](https://openairdocs.org/ntsb-events/150): 1 cases - [Landing gear not configured](https://openairdocs.org/ntsb-events/095): 1 cases - [Dragged wing/rotor/float/other](https://openairdocs.org/ntsb-events/093): 1 cases ## Aircraft models (registry) - [Cessna 172RG](https://openairdocs.org/model/cessna-172rg): 3 cases - [Cessna T210L](https://openairdocs.org/model/cessna-t210l): 2 cases - [Cessna 210C](https://openairdocs.org/model/cessna-210c): 2 cases - [Bombardier CL-600-2B19](https://openairdocs.org/model/bombardier-cl-600-2b19): 2 cases - [Piper PA 46-350P](https://openairdocs.org/model/piper-pa-46-350p): 1 cases - [Piper PA-32R-300](https://openairdocs.org/model/piper-pa-32r-300): 1 cases - [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350): 1 cases - [Piper PA-28R-200](https://openairdocs.org/model/piper-pa-28r-200): 1 cases - [Piper PA-28-235](https://openairdocs.org/model/piper-pa-28-235): 1 cases - [Piper L-4J](https://openairdocs.org/model/piper-l-4j): 1 cases ## Other findings in the same cases - [Brake](https://openairdocs.org/ntsb-findings/01023242) (Aircraft): 7 cases - [Gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230) (Aircraft): 6 cases - [Main landing gear](https://openairdocs.org/ntsb-findings/01023210) (Aircraft): 5 cases - [Landing gear brakes system](https://openairdocs.org/ntsb-findings/01023240) (Aircraft): 4 cases - [Not determined, general](https://openairdocs.org/ntsb-findings/05000000) (Not determined): 3 cases - [Scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010) (Personnel issues): 3 cases - [Landing gear actuator](https://openairdocs.org/ntsb-findings/01023233) (Aircraft): 3 cases - [Pump, main](https://openairdocs.org/ntsb-findings/01022913) (Aircraft): 3 cases - [CRM/MRM techniques](https://openairdocs.org/ntsb-findings/02063540) (Personnel issues): 2 cases - [Lack of action](https://openairdocs.org/ntsb-findings/02041030) (Personnel issues): 2 cases ## Newest cases - [NTSB ERA25LA314](https://openairdocs.org/ntsb/ERA25LA314), Aug 20, 2025: Piper PA32R (N990DM), Miami, FL, substantial damage. Probable cause: An inflight loss of hydraulic fluid from the landing gear system through a cracked fitting, which resulted in a landing gear collapse upon touchdown. - [NTSB WPR25LA178](https://openairdocs.org/ntsb/WPR25LA178), Apr 4, 2025: Piper PA-28R-200 (N9404N), Vancouver, WA, substantial damage. Probable cause: A failure of the brake system during landing due to a hydraulic fluid leak, which resulted in a runway excursion. - [NTSB ERA24LA051](https://openairdocs.org/ntsb/ERA24LA051), Nov 28, 2023: Lancair 235 (N235N), Stuart, FL, substantial damage. Probable cause: A landing gear collapse due to a hydraulic fluid leak in the landing gear system. - [NTSB WPR23LA076](https://openairdocs.org/ntsb/WPR23LA076), Dec 26, 2022: Cessna 210N (N210CU), Morgan, UT, substantial damage. Probable cause: Failure of the brake system O-rings on the left landing gear trunnion, which allowed the hydraulic fluid to drain from the left brake system, resulting in a runway excursion and impact with a fence. - [NTSB WPR22LA341](https://openairdocs.org/ntsb/WPR22LA341), Sep 7, 2022: Cessna 750 (N15TZ), Mesa, AZ, substantial damage. Probable cause: The pilot’s improper decision to depart on the accident flight with a known hydraulic leak, resulting in an in-flight hydraulic system failure, and the pilot’s attempt to land during an unstabilized… - [NTSB WPR21LA362](https://openairdocs.org/ntsb/WPR21LA362), Mar 28, 2021: Maule MX-7-235 (N235X), Ontario, OR, substantial damage. Probable cause: A loss of hydraulic fluid and failure of the right brake for reasons that could not be determined due to a lack of available evidence. - [NTSB WPR20LA172](https://openairdocs.org/ntsb/WPR20LA172), May 9, 2020: Ayres S2R (N2245S), Imperial, CA, substantial damage. Probable cause: The pilot's loss of control during a landing roll due to a failure of the main O-ring in the right brake assembly, which resulted in a loss of brake pressure and subsequent brake failure. - [NTSB WPR20LA104](https://openairdocs.org/ntsb/WPR20LA104), Feb 28, 2020: Piper PA46 (N304LA), San Jose, CA, substantial damage. Probable cause: The failure to properly service the hydraulic power pack prevented a normal landing gear extension. Contributing to the accident was the failure of the landing gear emergency release valve to… - [NTSB ANC20LA013](https://openairdocs.org/ntsb/ANC20LA013), Jan 12, 2020: Piper PA31 (N4112K), Fairbanks, AK, substantial damage. Probable cause: The improper installation of a hydraulic line at the right main landing gear (MLG) unlock actuator, which resulted in a total loss of system hydraulic pressure and failure of the landing gear to… - [NTSB ERA19LA239](https://openairdocs.org/ntsb/ERA19LA239), Jul 30, 2019: Cessna 210 (N2362F), Chattanooga, TN, substantial damage. Probable cause: The improper maintenance of the airplane’s landing gear system, which resulted in a hydraulic fluid leak and insufficient pressure to extend and lock the landing gear during the accident flight. NTSB has coded findings and defining events since 2008; earlier cases used its older occurrence and cause codes and aren't counted. Findings: https://openairdocs.org/ntsb-findings.md. Defining events: https://openairdocs.org/ntsb-events.md. Phases of flight: https://openairdocs.org/ntsb-phases.md. Every investigation, filtered by finding, event, phase, state, year or model: https://openairdocs.org/ntsb.md (for example ?state=MI&fatal=1). NTSB's definitions: Accident and incident, 49 CFR 830.2 (https://www.ecfr.gov/current/title-49/subtitle-B/chapter-VIII/part-830/subpart-A/section-830.2), CICTT occurrence categories (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/OccurrenceCategoryDefinitions.pdf), CICTT phases of flight (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/PhaseofFlightDefinitions.pdf), and NTSB coding manual, before 2008 (PDF) (https://www.ntsb.gov/GILS/Documents/codman.pdf). NTSB publishes no definitions for its findings, only their names. --- 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.