# NTSB LAX85LA147: Bell 47G-2, N4021A, Stockton, CA, February 20, 1985

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: February 20, 1985, 09:00 local (17:00 UTC)
- Place: Stockton, CA
- Location: 37.9577° N, 121.2908° W: Placed by OpenAirDocs: center of Stockton, CA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=37.9577&lon=-121.2908&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 24656
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX85LA147
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/24656/pdf
- Page: https://openairdocs.org/ntsb/LAX85LA147

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power, cruise - normal
  - reason for occurrence undetermined (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - high vegetation

## Analysis

THE ENG EXPERIENCED A TTL LOSS OF PWR DURING CRUISE FLT AT 300-400 FT AGL. THE PLT PERFORMED AN AUTOROTATION INTO A GRAPE VINEYARD WHICH RESULTED IN SUBSTANTIAL DAMAGE TO THE HELICOPTER. CAUSE OF THE LOSS OF PWR WAS NOT DETERMINED.

## Aircraft

- Registration: [N4021A](https://openairdocs.org/deregistered/N4021A-1988-10-06), registration cancelled 1988-10-06, S/N 1879 (OpenAirDocs)
- Reported make and model: BELL 47G-2
- Registry model: [Bell 47G-2](https://openairdocs.org/model/bell-47g-2) (registry code 1181008) (OpenAirDocs)
- Category: Helicopter
- Airframe hours: 2100
- Engines: LYCOMING VO-435-A1B 200 horsepower reciprocating
- Damage: Substantial damage
- Flight: Business, Part 91
- Registered owner: Robert E. Mills
- Airworthiness certificate: Standard, Utility
- Departed: 015, TURLOCK, CA
- Destination: SCK, STOCKTON, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 11,000 total, 350 in this make and model, 10,800 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 25 knots, gusting 30
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 50 °F, dew point 30 °F
- Altimeter: 29.00 inHg

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19850220030789A](https://openairdocs.org/incident/19850220030789A), Feb 20, 1985: Bell 47G2, Stockton, CA, Substantial damage. Autorotation to vineyard when engine lost power during cruise. Cause not reported at this time.

## Other investigations on N4021A (2)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB LAX82FA077](https://openairdocs.org/ntsb/LAX82FA077), Feb 19, 1982: Bell 47G2 (N4021A), Brawley, CA, substantial damage
- [NTSB UNK64X1865](https://openairdocs.org/ntsb/UNK64X1865), May 20, 1964: Bell 47G-2 (N4021A), Enterprise, OR, substantial damage

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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