# NTSB investigations: Lycoming VO-540 series, 1991

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 FTW92LA007](https://openairdocs.org/ntsb/FTW92LA007.md): Hiller UH-12E · Palacios, TX · Accident · No injuries · Limited investigation · Final report · Oct 11, 1991 · N4029D · Substantial damage
  > The pilot's inadequate preflight.
- [NTSB LAX91LA388](https://openairdocs.org/ntsb/LAX91LA388.md): Texas Helicopter M74 · Farmington, CA · Accident · 1 fatal · Limited investigation · Final report · Sep 11, 1991 · N43921 · Destroyed
  > Loss of engine power for an undetermined reason. Factors related to the accident were: the excessive gross weight of the helicopter, and the pilot's improper use of flight controls due to impairment from use of a drug (marijuanna).
- [NTSB LAX91LA363](https://openairdocs.org/ntsb/LAX91LA363.md): Bell 47G · Kettleman City, CA · Accident · Minor injuries · Limited investigation · Final report · Aug 20, 1991 · N4062G · Substantial damage
  > A non-mechanical loss of engine power due to fuel exhaustion by the pilot's improper calculation of the fuel supply and subsequent hard landing.
- [NTSB FTW91DRD06](https://openairdocs.org/ntsb/FTW91DRD06.md): Bell 47-G2 · White Castle, LA · Accident · No injuries · Final report · Jun 26, 1991 · N8460E · Destroyed
  > The pilot's improper aircraft handling, which resulted in settling with power.
- [NTSB LAX91LA249](https://openairdocs.org/ntsb/LAX91LA249.md): Hiller UH-12E · Huron, CA · Accident · No injuries · Limited investigation · Final report · Jun 7, 1991 · N507HA · Substantial damage
  > That unknown pilot(s) impoperly used the throttle control which caused an overspeed condition. Contributing to this accident was the connecting rod bolt fatigue failure.
- [NTSB LAX91LA191](https://openairdocs.org/ntsb/LAX91LA191.md): Hiller UH-12E · Delano, CA · Accident · No injuries · Limited investigation · Final report · May 4, 1991 · N4414 · Substantial damage
  > That the pilot improperly performed the autorotation by misjudging the flare altitude. Contributing to this accident was the total failure of the freewheeling sprag clutch due to excessive wear and the soft dirt terrain.
- [NTSB FTW91LA064](https://openairdocs.org/ntsb/FTW91LA064.md): Bell 47G4 · Corpus Christi, TX · Accident · Minor injuries · Limited investigation · Final report · Apr 27, 1991 · N1195W · Destroyed
  > The initial restricted movement and eventual locking of the cyclic control as a result of the failure of the lateral servo. A factor was the installation of the failed component by an unqualified person.
- [NTSB ANC91LA041](https://openairdocs.org/ntsb/ANC91LA041.md): Bell 47 · Thompson Pass, AK · Accident · No injuries · Limited investigation · Final report · Mar 30, 1991 · N73279 · Substantial damage
  > The pilot's failure to maintain aircraft control and improper flare during landing.

## 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 year(c."eventDate") = 1991
  AND c."mKey" IN (SELECT x.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' x WHERE x.engine_model_code IN ('41534', '41582'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb?engine=41534&year=1991

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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.