# NTSB investigations: Franklin 6V4 series, MN

NTSB aviation accident and incident investigations since 1962: the probable cause, findings, aircraft, crew, weather and docket of each, linked to the FAA registry and the FAA’s own reports.

## Latest cases

- [NTSB CEN17LA264](https://openairdocs.org/ntsb/CEN17LA264.md): Bell 47D1 · Big Lake, MN · Accident · No injuries · Limited investigation · Final report · Jul 6, 2017 · N153B · Substantial damage
  > The failure of the metal core assembly within a wooden main rotor blade due to undetected corrosion and fatigue, which caused the wooden blade to separate from the rotor mast.
- [NTSB CHI82DA196](https://openairdocs.org/ntsb/CHI82DA196.md): Bell 47D1 · Le Sueur, MN · Accident · No injuries · Final report · May 29, 1982 · N4251A · Substantial damage
  > During a spraying operation, the aircraft was being refueled from a 200 gal fuel tank, mounted on the rear of a truck. The truck was parked on a slight slope with the outlet for the servicing hose at the lower end. After the helicopter was serviced with 14…

## The whole list in SQL

Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS:

```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" = 'MN' 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
```

This list as a web page: https://openairdocs.org/ntsb?engine=27033&state=MN

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OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.