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Mast bumping

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NTSB defining event · CICTT: Loss Of Control (Inflight)

CICTT occurrence categories (PDF)CICTT phases of flight (PDF)

All 9 cases18 anywhere in the sequence
Defining event in
9 cases
In the sequence of
18 cases
Fatal cases
7
NTSB code
245

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 it was the defining event; in gray, cases where it came elsewhere in the sequence. The map shows the cases where it was the defining event. Events are coded with the final report, so the latest years are incomplete.

Cases per year

2008Defining eventElsewhere in the sequence2026

Where

Open the map
Query with SQL
duckdb -csv -c "SELECT year(c.\"eventDate\") AS year, count(DISTINCT e.case_mkey) AS cases,
    count(DISTINCT e.case_mkey) FILTER (WHERE e.\"isDefiningEvent\") AS defining
  FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' e JOIN 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c ON c.\"mKey\" = e.case_mkey
  WHERE e.\"tier2Number\" = '245' AND e.case_mkey IN (SELECT case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' WHERE \"isDefiningEvent\")
  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 these cases

Phase of flight
  • Enroute3
  • Maneuvering2
  • Enroute-cruise2
  • Maneuvering-low-alt flying1
  • Taxi-to runway1
In the probable cause
Aircraft models

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

Query with SQL
duckdb -csv -c "WITH defining AS (SELECT * FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' WHERE \"tier2Number\" = '245' AND \"isDefiningEvent\")
  SELECT * FROM (
  SELECT 'Phase of flight' AS kind, e.\"tier1Number\" AS code, max(e.\"eventTier1Name\") AS name, count(DISTINCT e.case_mkey) AS cases
  FROM defining e
  GROUP BY ALL
  UNION ALL
  SELECT 'Finding in the probable cause', left(f.\"findingCode\", 8), max(f.\"tier4Name\"), count(DISTINCT f.case_mkey)
  FROM defining e JOIN 'https://openairdocs.org/data/latest/ntsb_findings.parquet' f ON f.case_mkey = e.case_mkey AND f.aircrafts_position = e.aircrafts_position AND f.\"inProbableCause\"
  WHERE f.\"findingCode\" GLOB '[0-9][0-9]*'
  GROUP BY ALL
  UNION ALL
  SELECT 'Aircraft model', a.aircraft_model_code, any_value(concat_ws(' ', m.manufacturer, m.model)), count(DISTINCT e.case_mkey)
  FROM defining e JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = e.case_mkey AND a.position = e.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
  )
  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 · 9

NTSB ERA26LA324Accident · No injuriesClass 4 · LimitedInvestigation openCSP Leasing Cavalon · Ronkonkoma, NYAug 30, 2026 · N203AG · Substantial damageNTSB ANC24FA063Accident · 3 fatalClass 3 · FieldFinal reportRobinson Helicopter R44 · Kekaha, HIAn encounter with turbulence due to downdraft winds that resulted in mast bumping and an in-flight breakup.Jul 11, 2024 · N144KW · Substantial damageNTSB CEN24FA248Accident · 1 fatalClass 3 · FieldFinal reportRotorway Scorpion 133 · Andale, KSThe pilot’s abrupt control inputs, which resulted in a low-G condition, main rotor mast bumping, and subsequent severing of the tailboom by the main rotor blades.Jul 5, 2024 · N51017 · DestroyedNTSB WPR23LA313Accident · Minor injuriesClass 3 · LimitedFinal reportBell OH-58A · Guernsey, CAThe pilot’s overpitching of the main rotor blades while maneuvering at low altitude in a high-temperature environment at high gross weight, which resulted in a reduction of engine and rotor speed, excessive main rotor blade flapping, mast bumping, and impact…Aug 9, 2023 · N861CC · Substantial damageNTSB WPR19FA109Accident · 2 fatalClass 3 · FieldFinal reportBell 206 · Fort McDowell, AZThe separation of the main rotor head from the mast as a result of a sudden displacement of the cyclic stick during a low-G maneuver, leading to mast bumping. Contributing to the accident were the unsecure positioning of the flight test engineer’s laptop…Apr 16, 2019 · N61PH · DestroyedNTSB CEN18WA402Accident · 1 fatalForeign investigationRotorway Exec · Crestet, FranceThe government of France has notified the NTSB of an accident involving an amateur-built ROTORWAY EXEC helicopter that occurred on April 05, 2018. The NTSB has appointed a U.S. Accredited Representative to assist the government of France's investigation under…Apr 5, 2018 · F-PFBJ · DestroyedNTSB CEN17FA012Accident · 2 fatalField investigationFinal reportFairchild Hiller FH 1100 · Lino Lakes, MNThe separation of the main rotor assembly due to mast bumping.Oct 6, 2016 · N4035G · DestroyedNTSB WPR16FA130Accident · 2 fatalField investigationFinal reportRobinson Helicopter R66 · Wikieup, AZAn encounter with turbulence due to updrafts and/or dust devils that resulted in mast bumping and an in-flight break-up.Jun 23, 2016 · N117TW · DestroyedNTSB CEN11FA422Accident · 1 fatalField investigationFinal reportRobinson R22 Beta · Del Valle, TXThe divergence of the main rotor from its normal plane of rotation for reasons that cannot be determined because the pilot’s control inputs leading up to the event are unknown, resulting in mast bumping and main rotor blade separation.Jun 27, 2011 · N7779M · Substantial damage
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 e.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' e WHERE e.\"isDefiningEvent\" AND e.\"tier2Number\" = '245')
  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.