# NTSB SEA70D0079: Bell 47G-3, N6787D, Circle, MT, September 12, 1969

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Closed
- Date: September 12, 1969
- Place: Circle, MT · CIRCLE, MT
- Location: 47.4177° N, 105.5870° W: Placed by OpenAirDocs: center of Circle, MT, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=47.4177&lon=-105.5870&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report May 18, 1970
- Report: Brief approved by the director
- NTSB case key (mKey): 152560
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA70D0079
- Page: https://openairdocs.org/ntsb/SEA70D0079

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-4196  69/9/12    CIRCLE,MONT         BELL 47G-3          CR-  0  0  1  COMMERCIAL                COMMERCIAL, FL.INSTR.,
        TIME - 1400                    N6787D              PX-  0  0  1  POWER/PIPELINE            AGE 44, 3290 TOTAL HOURS,
                                       DAMAGE-SUBSTANTIAL  OT-  0  0  0                            90 IN TYPE, NOT
                                                                                                   INSTRUMENT RATED.
        DEPARTURE POINT             INTENDED DESTINATION
          CIRCLE,MONT                 CIRCLE,MONT
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           PROPELLER/ROTOR FAILURE: TAIL ROTOR                      IN FLIGHT: NORMAL CRUISE
           HARD LANDING                                             LANDING: ROLL-ON/RUN-ON
        PROBABLE CAUSE(S)
           ROTORCRAFT - TRANSMISSION ROTOR DRIVE SYSTEM: TAIL ROTOR DRIVE SHAFT ASSEMBLY
           MISCELLANEOUS ACTS,CONDITIONS - MATERIAL FAILURE
           PILOT IN COMMAND - IMPROPER OPERATION OF FLIGHT CONTROLS
        EMERGENCY CIRCUMSTANCES - FORCED LANDING OFF AIRPORT ON LAND
        REMARKS- AFT SHAFT SECTION FAILED.
```

## Aircraft

- Registration: [N6787D](https://openairdocs.org/deregistered/N6787D-1980-12-08), registration cancelled 1980-12-08, S/N 2594 (OpenAirDocs)
- Reported make and model: BELL 47G-3
- Registry model: [Bell 47G-3](https://openairdocs.org/model/bell-47g-3) (registry code 1181024) (OpenAirDocs)
- Category: Helicopter
- Engines: reciprocating
- Damage: Substantial damage

## Other investigations on N6787D (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 OAK72DVD03](https://openairdocs.org/ntsb/OAK72DVD03), Jul 11, 1971: Bell 47G3 (N6787D), Tracy, CA, substantial damage
- [NTSB SEA70FDA06](https://openairdocs.org/ntsb/SEA70FDA06), May 1, 1970: Bell 47G3 (N6787D), Jordan, MT, 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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