# NTSB SEA72FTA17: Bell 47G-3B, N204Z, Harlowton, MT, April 27, 1972

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Closed
- Date: April 27, 1972
- Place: Harlowton, MT · HARLOWTON, MT
- Location: 46.4368° N, 109.8345° W: Placed by OpenAirDocs: center of Harlowton, MT, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=46.4368&lon=-109.8345&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report February 14, 1973
- Report: Brief approved by the director
- NTSB case key (mKey): 166002
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA72FTA17
- Page: https://openairdocs.org/ntsb/SEA72FTA17

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-1958  72/4/27    HARLOWTON,MONT      BELL 47G-3B         CR-  0  0  3  COMMERCIAL                COMMERCIAL, AGE 28, 2610
        TIME - 1230                    N204Z               PX-  0  0  0  MAPPING/PHOTO             TOTAL HOURS, 325 IN TYPE,
                                       DAMAGE-SUBSTANTIAL  OT-  0  0  0                            NOT INSTRUMENT RATED.
        DEPARTURE POINT             INTENDED DESTINATION
          HARLOWTON,MONT              LOCAL
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           ENGINE FAILURE OR MALFUNCTION                            IN FLIGHT: NORMAL CRUISE
           HARD LANDING                                             LANDING: POWER-OFF AUTOROTATIVE LANDING
        PROBABLE CAUSE(S)
           POWERPLANT - ENGINE STRUCTURE: PISTON,PISTON RINGS
           MISCELLANEOUS ACTS,CONDITIONS - MATERIAL FAILURE
           PILOT IN COMMAND - FAILED TO MAINTAIN ADEQUATE ROTOR R.P.M.
        PARTIAL POWER LOSS - PARTIAL LOSS OF POWER - 1 ENGINE
        EMERGENCY CIRCUMSTANCES - FORCED LANDING OFF AIRPORT ON LAND
        REMARKS- BROKEN PISTON RING FOUND ON TEAR DOWN
```

## Aircraft

- Registration: [N204Z](https://openairdocs.org/deregistered/N204Z-2002-10-04), registration cancelled 2002-10-04, S/N 3449, built 1961 (OpenAirDocs)
- Reported make and model: BELL 47G-3B
- Registry model: [Bell 47G-3B](https://openairdocs.org/model/bell-47g-3b) (registry code 1181026) (OpenAirDocs)
- Registry engine: [Lycoming TVO-435-GIA](https://openairdocs.org/engine/lycoming-tvo-435-gia) (registry code 41526, turbo-prop) (OpenAirDocs)
- Category: Helicopter
- Engines: reciprocating
- Damage: Substantial damage

## Other investigations on N204Z (3)

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 DEN83LA002](https://openairdocs.org/ntsb/DEN83LA002), Oct 5, 1982: Bell 47G3B (N204Z), Nr. Englewood, CO, destroyed
- [NTSB SEA73FTA06](https://openairdocs.org/ntsb/SEA73FTA06), Apr 23, 1973: Bell 47G-3B (N204Z), Billings, MT, substantial damage
- [NTSB MIA69F0341](https://openairdocs.org/ntsb/MIA69F0341), Jan 18, 1969: Bell 47G-3B (N204Z), Kingsport, TN, 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.

---
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.