# NTSB SEA66A0030: Brantly B-2, N5991X, Bigfork, MT, November 3, 1965

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Closed
- Date: November 3, 1965
- Place: Bigfork, MT · BIGFORK, MT
- Location: 48.0633° N, 114.0726° W: Placed by OpenAirDocs: center of Bigfork, MT, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=48.0633&lon=-114.0726&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report April 21, 1966
- Report: Brief approved by the director
- NTSB case key (mKey): 174978
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA66A0030
- Page: https://openairdocs.org/ntsb/SEA66A0030

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
2-0990   65/11/3 NR.BIGFORK MONT       BRANTLY B-2         CR-  0  0  1  MISCELLANEOUS             COMMERCIAL, FL.INSTR.,
        TIME - 1045                    N5991X              PX-  0  0  0  FERRY                     AGE 37, 15000 TOTAL
                                       DAMAGE-DESTROYED    OT-  0  0  0                            HOURS, 250 IN TYPE,
                                                                                                   INSTRUMENT RATED.
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           ENGINE FAILURE OR MALFUNCTION                            IN FLIGHT: NORMAL CRUISE
           MISCELLANEOUS                                            STATIC: IDLING ROTORS
        PROBABLE CAUSE(S)
           POWERPLANT - MISCELLANEOUS: POWERPLANT FAILURE FOR UNDETERMINED REASONS
           TERRAIN - ROUGH/UNEVEN
        PARTIAL POWER LOSS - PARTIAL LOSS OF POWER - 1 ENGINE
        EMERGENCY CIRCUMSTANCES - FORCED LANDING OFF AIRPORT ON LAND
                                  SUSPECTED MECHANICAL DISCREPANCY
         FIRE AFTER IMPACT
        REMARKS- SUSPECTED CARB ICE.LANDED NEAR CLIFF EDGE.PILOT GOT OUT.ACFT FELL OFF CLIFF.ENGINE INACCESSIBLE.
```

## Aircraft

- Registration: [N5991X](https://openairdocs.org/deregistered/N5991X-1966-02-23), registration cancelled 1966-02-23, S/N 135 (OpenAirDocs)
- Reported make and model: BRANTLY B-2
- Registry model: [Brantly B-2](https://openairdocs.org/model/brantly-b-2) (registry code 1440502) (OpenAirDocs)
- Category: Helicopter
- Engines: reciprocating
- Damage: 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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