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Mountainous/hilly terrain

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NTSB finding · Environmental issues › Physical environment › Terrain

All 329 cases127 in the probable cause
Cases
329
In the probable cause
127 (39%)
Fatal cases
187
NTSB code
03021010

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\", '03021010') 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\", '03021010'))
  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\", '03021010') 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 · 329

NTSB CEN26LA300Accident · Minor injuriesClass 4 · LimitedFinal reportCessna T206H · Marble, COThe pilot's failure to maintain directional control during the final approach in variable and gusting wind conditions. Contributing to the accident were localized wind effects associated with mountainous terrain and with nearby convective activity.Aug 21, 2026 · N464PM · Substantial damageNTSB WPR26LA234Accident · No injuriesClass 4 · LimitedFinal reportPiper PA-12 · Dixie, IDThe pilot's delayed decision to initiate a go-around and subsequent failure to maintain clearance from rising terrain.Jun 23, 2026 · N3013M · Substantial damageNTSB WPR26LA123Accident · Serious injuriesClass 4 · LimitedFinal reportBrunner Donald G Kitfox · Rock Crossing, AZAn encounter with a downdraft while maneuvering at a low altitude, which resulted in an impact with terrain.Mar 10, 2026 · N104DG · Substantial damageNTSB ANC25LA085Accident · No injuriesClass 4 · LimitedFinal reportDehavilland DHC-2 MK 1 · Soldotna, AKThe pilot’s failure to maintain clearance from rising terrain while maneuvering at low altitude.Aug 9, 2025 · N232KT · Substantial damageNTSB CEN25LA240Accident · No injuriesClass 4 · LimitedFinal reportCub Crafters CCK-1865 · La Garita, COThe pilot’s failure to maintain clearance from terrain while maneuvering at low altitude in mountainous terrain. Contributing was the pilot’s inadequate preflight planning and aeronautical decision making.Jul 7, 2025 · N952SA · Substantial damageNTSB WPR25LA080Accident · 1 fatalClass 3 · LimitedFinal reportPiper PA-32-300 · Round Mountain, NVImpact with mountainous terrain for reasons that could not be determined due to a lack of available evidence.Jan 2, 2025 · N4151R · Substantial damageNTSB CEN25FA047Accident · 2 fatalClass 3 · FieldFinal reportCessna 182T · Drake, COThe pilot’s failure to maintain airplane control while maneuvering in mountainous terrain. Contributing was mountain wave turbulence in the area.Nov 23, 2024 · N434CP · DestroyedNTSB ERA25FA037Accident · 1 fatalClass 3 · FieldFinal reportCessna 150F · Wilder, TNThe student pilot’s decision to continue the visual flight rules flight into instrument meteorological conditions at night, which resulted in controlled flight into terrain.Oct 31, 2024 · N8110S · DestroyedNTSB WPR25LA006Accident · Minor injuriesClass 4 · LimitedFinal reportAgustawestland AW109SP · Kamas, UTThe pilot’s exceedance of the helicopter’s available power while landing in a confined area, which resulted in a loss of tail rotor effectiveness and a hard landing.Oct 8, 2024 · N631HC · Substantial damageNTSB WPR24FA298Accident · 1 fatalClass 3 · FieldFinal reportBoeing A75L3 · Yacolt, WAThe pilot’s exceedance of the airplane’s critical angle of attack while maneuvering at a low altitude in mountainous terrain in moderately high density altitude conditions, resulting in an aerodynamic stall and subsequent impact with terrain.Sep 6, 2024 · N53466 · Substantial damage
See all 329 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\", '03021010'))
  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.