# NTSB OAK75AP011: Bell 47J-2A, N3072G, Ripon, CA, September 9, 1974

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Closed
- Date: September 9, 1974
- Place: Ripon, CA · RIPON, CA
- Location: 37.7420° N, 121.1304° W: Placed by OpenAirDocs: center of Ripon, CA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=37.7420&lon=-121.1304&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal, 1 serious
- Status: Completed, report March 4, 1975
- Report: Brief approved by the director
- NTSB case key (mKey): 138630
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=OAK75AP011
- Page: https://openairdocs.org/ntsb/OAK75AP011

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-4207   74/9/9    RIPON,CALIF         BELL 47J-2A         CR-  0  1  0  COMMERCIAL                COMMERCIAL, FL.INSTR.,
        TIME - 1012                    N3072G              PX-  2  0  0  MAPPING/PHOTO             AGE 32, 4700 TOTAL HOURS,
                                       DAMAGE-DESTROYED    OT-  0  0  0                            124 IN TYPE, NOT
                                                                                                   INSTRUMENT RATED.
        DEPARTURE POINT             INTENDED DESTINATION
          STOCKTON,CALIF              NEW MELONE DAM,CALIF
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           PROPELLER/ROTOR FAILURE: TAIL ROTOR                      IN FLIGHT: NORMAL CRUISE
           COLLISION WITH GROUND/WATER: UNCONTROLLED                LANDING: POWER-ON LANDING
        PROBABLE CAUSE(S)
           ROTORCRAFT - TRANSMISSION ROTOR DRIVE SYSTEM: TAIL ROTOR DRIVE SHAFT ASSEMBLY
           MISCELLANEOUS ACTS,CONDITIONS - LACK OF LUBRICATION-SPECIFIC PART,NOT SYSTEM
           PERSONNEL - MAINTENANCE,SERVICING,INSPECTION: INADEQUATE MAINTENANCE AND INSPECTION
        FACTOR(S)
           PILOT IN COMMAND - INADEQUATE PREFLIGHT PREPARATION AND/OR PLANNING
         FIRE AFTER IMPACT
        REMARKS- TAIL ROTOR DRIVE SPLINED COUPLING FAILED.ACFT SPUN TO R AT LOW ALT.
```

## Aircraft

- Registration: [N3072G](https://openairdocs.org/deregistered/N3072G-1975-03-26), registration cancelled 1975-03-26, S/N 3129, built 1964 (OpenAirDocs)
- Reported make and model: BELL 47J-2A
- Registry model: [Bell 47J-2A](https://openairdocs.org/model/bell-47j-2a) (registry code 1181106) (OpenAirDocs)
- Category: Helicopter
- Engines: reciprocating
- Damage: Destroyed

## 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 19740909043559A](https://openairdocs.org/incident/19740909043559A), Sep 9, 1974: Bell 47J2A, Ripon, CA, Destroyed, 2 fatal. Tail rotor drive splined coupling failed. Acft spun to r at low alt.

## Other investigations on N3072G (1)

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 OAK66F0132](https://openairdocs.org/ntsb/OAK66F0132), Oct 20, 1965: Bell 47J2A (N3072G), Lihue, HI, destroyed

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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