# NTSB investigations: Lycoming VO-435 series, WI

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 GAA15CA122](https://openairdocs.org/ntsb/GAA15CA122.md): Continental Copters Tomcat MK5A · Elk Mound, WI · Accident · No injuries · Data collection · Final report · Jun 14, 2015 · N9045T · Substantial damage
  > The pilot's failure to maintain a positive rate of climb after taking off from the service truck, which resulted in the helicopter impacting terrain.
- [NTSB CHI08CA019](https://openairdocs.org/ntsb/CHI08CA019.md): Bell 47G-2A · Wautoma, WI · Accident · No injuries · Data collection · Final report · Oct 17, 2007 · N73223 · Substantial damage
  > The pilot's failure to maintain control of the helicopter resulting from a distraction in the cockpit. A contributing factor was the distraction due to the dog in the cockpit.
- [NTSB CHI94FA330](https://openairdocs.org/ntsb/CHI94FA330.md): Bell 47G-5A · Wisconsin Rpds, WI · Accident · 1 fatal · Field investigation · Final report · Mar 22, 1994 · N2991W · Destroyed
  > Undetermined.
- [NTSB CHI93DEP05](https://openairdocs.org/ntsb/CHI93DEP05.md): Bell 47-G5 · Fulton, WI · Accident · Minor injuries · Final report · Aug 25, 1993 · N1464W · Substantial damage
  > the failure (fracture) of the number one cylinder intake valve retainer (keeper).
- [NTSB CHI93LA179](https://openairdocs.org/ntsb/CHI93LA179.md): Bell 47 · Berlin, WI · Accident · Minor injuries · Limited investigation · Final report · May 21, 1993 · N8458E · Destroyed
  > The pilot-in-command's failure to see the obstruction.
- [NTSB CHI92LA137](https://openairdocs.org/ntsb/CHI92LA137.md): Bell 47-G2A · Dousman, WI · Accident · Serious injuries · Limited investigation · Final report · Apr 30, 1992 · N52HB · Substantial damage
  > The in-flight loss of the swash plate drive link bolt which allowed the swash plate drive assembly to disconnect.
- [NTSB CHI90DEP07](https://openairdocs.org/ntsb/CHI90DEP07.md): Bell 47-G2 · Hatley, WI · Accident · No injuries · Final report · Jul 10, 1990 · N6768D · Substantial damage
  > The partial loss of power due to sticking intake valves.
- [NTSB CHI86FA017](https://openairdocs.org/ntsb/CHI86FA017.md): Bell 47G-5 · Plainfield, WI · Accident · 1 fatal · Field investigation · Final report · Oct 27, 1985 · N7840S · Destroyed
  > The acft crashed into trees and nosed into the wooded terrain after a loss of powr. The helicopter had been refueled the day before the acc. Normal fuel load was 20 gals. The plt had sprayed 20 acres & flown 9 miles to another field to spray but aborted due…
- [NTSB CHI85LA338](https://openairdocs.org/ntsb/CHI85LA338.md): Bell 47G-5 · Pickett, WI · Accident · No injuries · Limited investigation · Final report · Aug 7, 1985 · N1476W · Substantial damage
  > The fld where this accident occurred had been sprayed one week prior to the accident by a fixed-wing acft at an alt of 20 ft. no wires were noted to be a hazard at that time. On the day of the accident the plt of the helicopter was talking to a spotter on the…
- [NTSB CHI84LA263](https://openairdocs.org/ntsb/CHI84LA263.md): Hiller UH 12 D · Deerfield, WI · Accident · Minor injuries · Limited investigation · Final report · Jun 26, 1984 · N62362 · Substantial damage
  > Plt was aware of pwr lines which crossed the field over which he was performing a calibration test. Plt stated that because of sun glare visual contact with the wires was lost. The acft contacted the wires.
- [NTSB CHI81DEP22](https://openairdocs.org/ntsb/CHI81DEP22.md): Bell 47G-5 · Coloma, WI · Accident · No injuries · Closed · Jun 12, 1981 · N1315X · Substantial damage
- [NTSB CHI78FEP14](https://openairdocs.org/ntsb/CHI78FEP14.md): Bell 47-J · Wilmot, WI · Accident · Minor injuries · Closed · Feb 5, 1978 · N6780D · Substantial damage
- [NTSB CHI73DEP66](https://openairdocs.org/ntsb/CHI73DEP66.md): Bell 47G-5 · Appleton, WI · Accident · Minor injuries · Closed · Jun 24, 1973 · N7840S · Substantial damage
- [NTSB CHI71DDJ11](https://openairdocs.org/ntsb/CHI71DDJ11.md): Bell 47D1 · Manitowish, WI · Accident · No injuries · Closed · Aug 21, 1970 · N4252A · Substantial damage

## 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" = 'WI' 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 ('41525'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb?engine=41525&state=WI

---
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.