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Hydraulic power system, general

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NTSB finding · Aircraft › Aircraft systems › Hydraulic power system

All 22 cases20 in the probable cause
Cases
22
In the probable cause
20 (91%)
Fatal cases
4
NTSB code
01022900

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\", '01022900') 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\", '01022900'))
  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\", '01022900') 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 · 22

NTSB ERA22LA148Accident · No injuriesClass 3 · LimitedFinal reportCessna 525 · Middle River, MDAnd undetermined failure of the brake system. Contributing to the accident was the failure of the pilots to locate and operate the emergency brake control, which resulted in a runway excursion and collision with terrain and an object.Mar 7, 2022 · N22AU · Substantial damageNTSB WPR21LA323Accident · No injuriesClass 3 · LimitedFinal reportCessna 177RG · Albuquerque, NMThe failure of the nose gear hydraulic flex line, which resulted in a loss of hydraulic fluid which prevented the main landing gear from fully extending and locking into place during landing.Aug 15, 2021 · N8029G · Substantial damageNTSB CEN21LA216Accident · No injuriesClass 3 · LimitedFinal reportAerospatiale AS350 B2 Ecureuil · Yukon, OKThe pilot receiving instruction’s untimely and unidentified inadvertent activation of the hydraulic cut-off switch, which turned off the hydraulic system while the helicopter was at slow airspeed followed by a rapid power increase, which resulted in a loss of…May 12, 2021 · N841BP · DestroyedNTSB CEN18LA349Accident · Serious injuriesLimited investigationFinal reportNorth American T-28B · Minneapolis, MNThe fire during approach for reasons that could not be determined based on the available evidence, which resulted in impact with terrain during approach for a precautionary landing.Aug 23, 2018 · N215SF · DestroyedNTSB ANC17LA014Accident · Serious injuriesLimited investigationFinal reportPiper PA 32R-300 · McGrath, AKThe failure of the nose landing gear to extend and lock due to the failure of the alternator and reduced battery power due to the cold ambient temperature, which prohibited the electrically-driven hydraulic pump from supplying adequate hydraulic pressure to…Nov 21, 2016 · N4352F · Minor damageNTSB WPR16FA040Accident · 2 fatalField investigationFinal reportAirbus Helicopters AS350 · Superior, AZThe pilot's loss of helicopter control in mountainous terrain as the result of operating the helicopter outside the performance envelope of its hydraulic system and encountering the servo transparency phenomenon. Contributing to the accident was the pilot's…Dec 16, 2015 · N74317 · Substantial damageNTSB WPR15LA234Accident · No injuriesLimited investigationFinal reportCessna 180J · Dixie, IDThe failure of the right brake hydraulic line during taxi due to fatigue, which caused a loss of hydraulic fluid and rendered the brake inoperative.Jul 26, 2015 · N52095 · Substantial damageNTSB CEN15MA290Accident · 1 fatalClass 1 · MajorFinal reportAirbus Helicopters AS350B3E · Frisco, COAirbus Helicopters' dual-hydraulic AS350 B3e helicopter's (1) preflight hydraulic check, which depleted hydraulic pressure in the tail rotor hydraulic circuit, and (2) lack of salient alerting to the pilot that hydraulic pressure was not restored before…Jul 3, 2015 · N390LG · DestroyedNTSB CEN14IA329Incident · No injuriesIncident investigationFinal reportEurocopter AS 350 B3 · Temple, TXThe pilot’s failure to reposition the yaw servo hydraulic switch to the “on” position during the pretakeoff hydraulic system check, which resulted in a complete lack of hydraulic boost to the tail rotor system and increased the load required to move the…Jun 26, 2014 · N808LF · Minor damageNTSB DCA13MA081Accident · 7 fatalClass 1 · MajorFinal reportBoeing 747-400 BCF · Bagram, AfghanistanNational Airlines' inadequate procedures for restraining special cargo loads, which resulted in the loadmaster's improper restraint of the cargo, which moved aft and damaged hydraulic systems Nos. 1 and 2 and horizontal stabilizer drive mechanism components,…Apr 29, 2013 · N949CA · Destroyed
See all 22 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\", '01022900'))
  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.