# NTSB investigations: Hydraulic, main system NTSB aviation accident and incident investigations since 1962: the probable cause, findings, aircraft, crew, weather and docket of each, linked to the FAA registry and the FAA’s own reports. ## Latest cases - [NTSB WPR26LA343](https://openairdocs.org/ntsb/WPR26LA343.md): Aerovodochody L-29 Delfin · Roswell, NM · Accident · No injuries · Class 4 · Limited · Final report · Sep 12, 2026 · N29AD · Substantial damage > The malfunction of a diode in the airplanes electrical system that resulted in low batter power and subsequent landing gear collapse. - [NTSB DCA26LA151](https://openairdocs.org/ntsb/DCA26LA151.md): Fairchild SA227-AC · Denver, CO · Accident · No injuries · Class 4 · Limited · Final report · Mar 7, 2026 · N425MA · Substantial damage > The overstress failure of the left main landing gear lower drag brace links during takeoff which resulted in a runway excursion during landing due to the left main landing gear collapsing. - [NTSB DCA24LA095](https://openairdocs.org/ntsb/DCA24LA095.md): Boeing 737-823 · Dallas, TX · Incident · No injuries · Class 2 · Limited · Final report · Feb 11, 2024 · N991AN · Minor damage > Improper maintenance due to human error during a braking system modification diminished braking performance. Contributing to the diminished braking performance was the lack of a functional check to verify the flexible hydraulic hoses and transducer wiring… - [NTSB DCA24FA002](https://openairdocs.org/ntsb/DCA24FA002.md): Boeing 757-236 · Chattanooga, TN · Accident · No injuries · Class 2 · Field · Final report · Oct 5, 2023 · N977FD · Substantial damage > The failure of the alternate gear extension system, which prevented the landing gear from being lowered. The cause of the system failure was a broken wire, due to tensile overload, between the alternate gear extend switch and the alternate extension power… - [NTSB ERA23LA202](https://openairdocs.org/ntsb/ERA23LA202.md): Rockwell International 112 · Miami, FL · Accident · No injuries · Class 3 · Limited · Final report · Apr 18, 2023 · N12RX · Substantial damage > Failure of the right main landing gear due to inadequate hydraulic pressure as result of a torn O-ring that was installed on the hydraulic pack’s check valve during overhaul. - [NTSB WPR22LA341](https://openairdocs.org/ntsb/WPR22LA341.md): Cessna 750 · Mesa, AZ · Accident · No injuries · Class 3 · Limited · Final report · Sep 7, 2022 · N15TZ · Substantial damage > 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 approach, which resulted in a loss of control during the… - [NTSB DCA21LA229](https://openairdocs.org/ntsb/DCA21LA229.md): Boeing 767-332 · Seattle, WA · Accident · Serious injuries · Class 4 · Limited · Final report · Sep 1, 2021 · N196DN · No damage > The flightcrew’s failure to set the hydraulic panel correctly during the execution of the pushback checklist, and when the hydraulic panel setting was corrected, that resulted in the airplane coming to a sudden stop and a flight attendant receiving a serious… - [NTSB WPR20LA280](https://openairdocs.org/ntsb/WPR20LA280.md): Arrow-Falcon Exporters UH-1H · Coalinga, CA · Accident · 1 fatal · Class 3 · Limited · Final report · Aug 19, 2020 · N711GH · Destroyed > The pilot’s inability to maintain control of the helicopter due to a hydraulic system failure for reasons that could not be fully determined due to the thermal destruction from the postimpact fire. - [NTSB CEN19LA246](https://openairdocs.org/ntsb/CEN19LA246.md): Swearingen SA227 · El Paso, TX · Accident · No injuries · Class 3 · Limited · Final report · Jul 27, 2019 · N681TR · Substantial damage > Failure of the left main landing gear to fully extend due to a lack of hydraulic fluid and during emergency extension procedures, which resulted in the collapse of the landing gear during landing and the subsequent runway excursion and collision with a sign. - [NTSB ERA18LA067](https://openairdocs.org/ntsb/ERA18LA067.md): Cessna 172RG · Martinsburg, WV · Accident · No injuries · Limited investigation · Final report · Jan 21, 2018 · N9415B · Substantial damage > A hydraulic leak in the right main landing gear actuator, which resulted in the main landing gear not extending. - [NTSB GAA17CA570](https://openairdocs.org/ntsb/GAA17CA570.md): Piper PA 31 · Saipan · Accident · No injuries · Data collection · Final report · Aug 30, 2017 · N4078J · Substantial damage > Impact with multiple birds while retracting the landing gear, which resulted in the subsequent failure of the right inboard main landing gear door actuator hose and prevented the pilot from being able to extend the landing gear. - [NTSB WPR17LA165](https://openairdocs.org/ntsb/WPR17LA165.md): Lake LA 4 · Byron, CA · Accident · No injuries · Class 3 · Limited · Final report · Jul 25, 2017 · N7628L · Substantial damage > The pilot’s failure to activate the hydraulic system during the approach, and his failure to ensure that the landing gear was down and locked before touchdown. Contributing to the accident was the pilot's decision to operate the airplane with an inoperative… - [NTSB WPR16LA187](https://openairdocs.org/ntsb/WPR16LA187.md): Jurcan Seawind 3000 · Renton, WA · Accident · No injuries · Limited investigation · Final report · Sep 18, 2016 · N57TJ · Substantial damage > The failure of the landing gear system to either fully retract or extend due to a cracked hydraulic fitting flare, which resulted in the loss of hydraulic pressure. - [NTSB ERA15LA296](https://openairdocs.org/ntsb/ERA15LA296.md): Bell 47G 3B 1 · Camden, AL · Accident · No injuries · Limited investigation · Final report · Aug 3, 2015 · N4002G · Substantial damage > A failure of the helicopter's hydraulic flight control systems for reasons that could not be determined due to the fire damage, and the pilot's inability to turn off the hydraulic system to relieve control pressure. - [NTSB CEN15IA014](https://openairdocs.org/ntsb/CEN15IA014.md): Raytheon Hawker · Denver, CO · Incident · No injuries · Incident investigation · Final report · Oct 15, 2014 · N694ES · Minor damage > The failure of the main landing gear tire, which resulted in separation of the servo block and subsequent total loss of all hydraulic system pressure and prevented the landing gear from extending before landing. - [NTSB WPR14TA248](https://openairdocs.org/ntsb/WPR14TA248.md): Lockheed SP 2H · Fresno, CA · Accident · No injuries · Final report · Jun 16, 2014 · N4692A · Substantial damage > The collapse of the nosewheel landing gear due to the disengagement of the nosewheel landing gear pin. Contributing to the accident was the failure of the main hydraulic system due to overpressurization for reasons that could not be determined during… - [NTSB WPR14FA137](https://openairdocs.org/ntsb/WPR14FA137.md): Eurocopter AS 350 B2 · Seattle, WA · Accident · 2 fatal · Field investigation · Final report · Mar 18, 2014 · N250FB · Destroyed > The loss of helicopter control due to a loss of hydraulic boost to the tail rotor pedal controls at takeoff, followed by a loss of hydraulic boost to the main rotor controls after takeoff. The reason for the loss of hydraulic boost to the main and tail rotor… - [NTSB CEN14LA127](https://openairdocs.org/ntsb/CEN14LA127.md): Piaggio P180 - Avanti II · Springfield, IL · Accident · No injuries · Limited investigation · Final report · Jan 31, 2014 · N700FE · Substantial damage > The pilot's decision to reengage the hydraulic system following the successful extension of the landing gear using the emergency extension procedures. Contributing to the accident was the failure of the directional control valve in the gear-up position and… - [NTSB WPR14LA105](https://openairdocs.org/ntsb/WPR14LA105.md): Piper PA 23-250 · Camarillo, CA · Accident · No injuries · Limited investigation · Final report · Jan 28, 2014 · N5977Y · Substantial damage > The inadequate hydraulic pressure due to a damaged O-ring in the hydraulic powerpack, which prevented the right main landing gear (MLG) downlock from locking in the extended positon and allowed the right MLG to collapse during landing. - [NTSB CEN12LA420](https://openairdocs.org/ntsb/CEN12LA420.md): Cessna T210M · Colorado Springs, CO · Accident · No injuries · Limited investigation · Final report · Jul 20, 2012 · N311TM · Substantial damage > The failure of the right hydraulic main gear down-lock actuator hose in flight. - [NTSB DCA12IA096](https://openairdocs.org/ntsb/DCA12IA096.md): Airbus A320 · Las Vegas, NV · Incident · No injuries · Incident investigation · Final report · Jun 17, 2012 · N552JB · No damage > the failure of the right main landing gear door retraction flexible hydraulic line in the Green hydraulic system, which led to prolonged operation of the power transfer unit and subsequent overheating and loss of pressure in the Yellow hydraulic system,… - [NTSB ANC12LA017](https://openairdocs.org/ntsb/ANC12LA017.md): Pzl-Swidnik SW-4 · Fairbanks, AK · Accident · No injuries · Limited investigation · Final report · Jan 15, 2012 · SP-SSW · Substantial damage > A loss of control during a simulated hydraulic emergency, which resulted in an inadvertent dynamic rollover from the which the pilot could not recover. - [NTSB ERA11WA472](https://openairdocs.org/ntsb/ERA11WA472.md): Agusta AW139 · Brazil · Accident · 4 fatal · Foreign investigation · Aug 19, 2011 · PR-SEK · Substantial damage > On August 19, 2011, at 1948 coordinated universal time (16:48 local time), an Agusta, AW139, helicopter, Brazilian registration PT-SEK, impacted into the Atlantic Ocean, near an oil rig, identifier P-65, the helicopter sank in waters with a recorded floor… - [NTSB CEN11FA359](https://openairdocs.org/ntsb/CEN11FA359.md): Eurocopter AS 350 B2 · Fort Worth, TX · Accident · Minor injuries · Field investigation · Final report · May 29, 2011 · N747CH · Substantial damage > The pilot’s loss of control due to his not maintaining adequate airspeed and altitude during a simulated hydraulic flight control failure. Contributing to the accident was the flight instructor’s inadequate supervision and delayed remedial response. - [NTSB ERA10TA501](https://openairdocs.org/ntsb/ERA10TA501.md): Eurocopter AS-350 · Covington, GA · Accident · Minor injuries · Final report · Sep 24, 2010 · N91DK · Substantial damage > The flight instructor's loss of control of the helicopter during the intentional demonstration of a low speed, hydraulics-off maneuver, that was warned against in the helicopter manufacturer's flight manual. - [NTSB CEN10TA355](https://openairdocs.org/ntsb/CEN10TA355.md): Lockheed P2V-5 · Broomfield, CO · Accident · No injuries · Final report · Jun 26, 2010 · N1386C · Substantial damage > The pilot’s failure to follow published emergency procedures by taxiing to the parking ramp with a known hydraulic system failure. Contributing to the accident was the co-pilot’s improper selection of the bypass position on the emergency nose gear extension… - [NTSB WPR09LA371](https://openairdocs.org/ntsb/WPR09LA371.md): Sikorsky S-55 · Chelan, WA · Accident · No injuries · Limited investigation · Final report · Jul 24, 2009 · N1255T · Substantial damage > Failure of a seal in the hydraulic system resulting in a loss of hydraulic pressure while maneuvering at low altitude. - [NTSB CEN09CA343](https://openairdocs.org/ntsb/CEN09CA343.md): Cessna 404 · Englewood, CO · Accident · No injuries · Data collection · Final report · Jun 6, 2009 · N37127 · Substantial damage > The failure of the landing gear to extend due to the failure of a hydraulic line. - [NTSB MIA08LA149](https://openairdocs.org/ntsb/MIA08LA149.md): Aero Commander 500-B · Charlotte Amali · Accident · No injuries · Limited investigation · Final report · Jun 1, 2008 · N411FS · Substantial damage > The failure of maintenance personnel to identify inadequate clamping of the aluminum line during inspection, and the undetected fatigue cracking of the line which resulted in the loss of hydraulic fluid. ## The whole list in SQL Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS: ```sql SELECT c."ntsbNumber", c."eventDate", c."eventType", c."eventCity", c."eventStateOrRegion", a.n_number, a."aircraftMake", a."aircraftModel", c."highestInjuryLevel", c."totalFatal", c."completionStatus", c.report_url FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = c."mKey" AND a.position = 1 WHERE c."mKey" IN (SELECT f.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' f WHERE starts_with(f."findingCode", '01022910')) ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC ``` This list as a web page: https://openairdocs.org/ntsb-findings/01022910/cases --- 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, except the copies of manufacturers’ service documents, which belong to their rights holders.