NTSB investigations: Franklin 6V4 series, OK

9 cases on aircraft whose registry engine model is Franklin 6V4 series. Aircraft are matched to the registry by N-number and event date, checked against the reported serial number, make and model, so older matches can be wrong.

Defining event

Finding

Phase of flight

Aircraft model

Cases per year

19742026

NTSB investigations: Franklin 6V4 series, OK per year, 1974–2026: 9 cases
1974	1
1975	1
1977	1
1980	1
1984	1
1994	2
1996	1
2001	1

Where

Open the map

Latest cases

Query with 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."eventStateOrRegion" = 'OK' AND c."eventCountry" = 'USA' AND c."mKey" IN (SELECT x.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' x WHERE x.engine_model_code IN ('27033')) ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC

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.\"eventStateOrRegion\" = 'OK' AND c.\"eventCountry\" = 'USA'
    AND c.\"mKey\" IN (SELECT x.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' x WHERE x.engine_model_code IN ('27033'))
  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.

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."eventStateOrRegion" = 'OK' AND c."eventCountry" = 'USA'
  AND c."mKey" IN (SELECT x.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' x WHERE x.engine_model_code IN ('27033'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC

Run it at the DuckDB prompt, or in any tool that reads Parquet over HTTPS. More ways to query the release are on Use the data.

NTSB FTW02LA044Accident · No injuriesLimited investigationFinal reportBell 47G · Ardmore, OKthe flight instructor's selection of an unsuitable area for practicing a full touchdown autorotation, which resulted in a nose over. A contributing factor was the soft ground.Dec 1, 2001 · N5226 · Substantial damage NTSB FTW96LA192Accident · No injuriesLimited investigationFinal reportBell 47D1 · Ardmore, OKthe student's inadvertent dynamic rollover, and inadequate supervision by the flight instructor.Apr 26, 1996 · N5226 · Substantial damage NTSB FTW94LA193Accident · No injuriesLimited investigationFinal reportBell 47H-1 · Tulsa, OKThe pilot's failure to maintain rotor RPM, his delayed landing flare, and the improper touchdown.Jun 4, 1994 · N2831B · Substantial damage NTSB FTW94LA166Accident · No injuriesLimited investigationFinal reportBell 47G · Sulphur, OKThe loss of engine power due to the failure of an engine accessory oil pump gear. A factor was the lack of suitable terrain for the autorotation.May 18, 1994 · N933B · Substantial damage NTSB FTW85LA074Accident · Serious injuriesLimited investigationFinal reportBell 47D1 · Ardmore, OKThe acft collided with power lines during a recovery from a practice autorotational landing. The instructor plt took control of the acft for recovery and did not see the wires.Dec 7, 1984 · N5226 · Substantial damage NTSB FTW80FPM14Accident · 1 fatalClosedBell 47G · Calvin, OKJul 16, 1980 · N16657 · Destroyed NTSB FTW77FPM13Accident · No injuriesClosedBell 47G · Copan, OKJun 15, 1977 · N16657 · Substantial damage NTSB FTW76FPJ19Accident · No injuriesClosedHiller Acft UH-12A · Ada, OKDec 13, 1975 · N8117H · Substantial damage NTSB FTW74FPM29Accident · No injuriesClosedEL Tomcat 47 · Zafra, OKJun 19, 1974 · N4227A · Destroyed