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Hydraulic, main system

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NTSB finding · Aircraft › Aircraft systems › Hydraulic power system

All 29 cases24 in the probable cause
Cases
29
In the probable cause
24 (83%)
Fatal cases
3
NTSB code
01022910

NTSB has coded findings and defining events since 2008. Earlier cases used its older occurrence and cause codes, so they aren’t counted here.

When and where

In green, cases where NTSB made it part of the probable cause; in gray, a factor or other finding. Findings are coded with the final report, often a year or more after the event, so the latest years are incomplete.

Cases per year

2008In the probable causeFactor only2026

Where

Open the map
Query with SQL
duckdb -csv -c "SELECT year(c.\"eventDate\") AS year, count(DISTINCT f.case_mkey) AS cases,
    count(DISTINCT f.case_mkey) FILTER (WHERE f.\"inProbableCause\") AS in_probable_cause
  FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' f JOIN 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c ON c.\"mKey\" = f.case_mkey
  WHERE starts_with(f.\"findingCode\", '01022910') AND c.\"eventDate\" >= DATE '2000-01-01'
  GROUP BY 1
  ORDER BY 1"

Prints the counts as CSV. It reads the release’s Parquet files over HTTPS, so there’s nothing to download first. Install DuckDB to run it.

In the same cases

Defining events
Aircraft models

Aircraft matched to the registry by N-number and date.

Other findings
Query with SQL
duckdb -csv -c "WITH matched AS (SELECT DISTINCT case_mkey, aircrafts_position FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' WHERE starts_with(\"findingCode\", '01022910'))
  SELECT * FROM (
  SELECT 'Defining event' AS kind, e.\"tier2Number\" AS code, max(e.\"eventTier2Name\") AS name, count(DISTINCT f.case_mkey) AS cases
  FROM matched f JOIN 'https://openairdocs.org/data/latest/ntsb_events.parquet' e ON e.case_mkey = f.case_mkey AND e.aircrafts_position = f.aircrafts_position AND e.\"isDefiningEvent\"
  WHERE e.\"tier2Number\" <> ''
  GROUP BY ALL
  UNION ALL
  SELECT 'Aircraft model', a.aircraft_model_code, any_value(concat_ws(' ', m.manufacturer, m.model)), count(DISTINCT f.case_mkey)
  FROM matched f JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = f.case_mkey AND a.position = f.aircrafts_position
  LEFT JOIN 'https://openairdocs.org/data/latest/faa_aircraft_model.parquet' m ON m.code = a.aircraft_model_code
  WHERE a.aircraft_model_code IS NOT NULL
  GROUP BY ALL
  UNION ALL
  SELECT 'Other finding', left(g.\"findingCode\", 8), max(g.\"tier4Name\"), count(DISTINCT g.case_mkey)
  FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' g
  WHERE g.case_mkey IN (SELECT case_mkey FROM matched) AND NOT starts_with(g.\"findingCode\", '01022910') AND g.\"findingCode\" GLOB '[0-9][0-9]*'
  GROUP BY ALL
  )
  QUALIFY row_number() OVER (PARTITION BY kind ORDER BY cases DESC) <= 10
  ORDER BY kind, cases DESC"

Prints the counts as CSV. It reads the release’s Parquet files over HTTPS, so there’s nothing to download first. Install DuckDB to run it.

Newest cases · 29

NTSB WPR26LA343Accident · No injuriesClass 4 · LimitedFinal reportAerovodochody L-29 Delfin · Roswell, NMThe malfunction of a diode in the airplanes electrical system that resulted in low batter power and subsequent landing gear collapse.Sep 12, 2026 · N29AD · Substantial damageNTSB DCA26LA151Accident · No injuriesClass 4 · LimitedFinal reportFairchild SA227-AC · Denver, COThe 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.Mar 7, 2026 · N425MA · Substantial damageNTSB DCA24LA095Incident · No injuriesClass 2 · LimitedFinal reportBoeing 737-823 · Dallas, TXImproper 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…Feb 11, 2024 · N991AN · Minor damageNTSB DCA24FA002Accident · No injuriesClass 2 · FieldFinal reportBoeing 757-236 · Chattanooga, TNThe 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…Oct 5, 2023 · N977FD · Substantial damageNTSB ERA23LA202Accident · No injuriesClass 3 · LimitedFinal reportRockwell International 112 · Miami, FLFailure 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.Apr 18, 2023 · N12RX · Substantial damageNTSB WPR22LA341Accident · No injuriesClass 3 · LimitedFinal reportCessna 750 · Mesa, AZThe 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…Sep 7, 2022 · N15TZ · Substantial damageNTSB DCA21LA229Accident · Serious injuriesClass 4 · LimitedFinal reportBoeing 767-332 · Seattle, WAThe 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…Sep 1, 2021 · N196DN · No damageNTSB WPR20LA280Accident · 1 fatalClass 3 · LimitedFinal reportArrow-Falcon Exporters UH-1H · Coalinga, CAThe 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.Aug 19, 2020 · N711GH · DestroyedNTSB CEN19LA246Accident · No injuriesClass 3 · LimitedFinal reportSwearingen SA227 · El Paso, TXFailure 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.Jul 27, 2019 · N681TR · Substantial damageNTSB ERA18LA067Accident · No injuriesLimited investigationFinal reportCessna 172RG · Martinsburg, WVA hydraulic leak in the right main landing gear actuator, which resulted in the main landing gear not extending.Jan 21, 2018 · N9415B · Substantial damage
See all 29 cases
Query with SQL
duckdb -csv -c "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"

Prints the whole list as CSV. It reads the release’s Parquet files over HTTPS, so there’s nothing to download first. Install DuckDB to run it.