# NTSB MKC76FTK02: Bell 47-G2A, N7578, Keystone, SD, July 25, 1975

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Closed
- Date: July 25, 1975
- Place: Keystone, SD · KEYSTONE, SD
- Location: 43.8949° N, 103.4268° W: Placed by OpenAirDocs: center of Keystone, SD, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=43.8949&lon=-103.4268&mi=10
- Phase of flight: [Uncontrolled descent](https://openairdocs.org/ntsb-phases/650) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor, 2 uninjured
- Status: Completed, report September 18, 1975
- Report: Brief approved by the director
- NTSB case key (mKey): 149977
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC76FTK02
- Page: https://openairdocs.org/ntsb/MKC76FTK02

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-2275  75/7/25    KEYSTONE,SD         BELL 47-G2A         CR-  0  0  1  COMMERCIAL                COMMERCIAL, AGE 23, 550
        TIME - 1430                    N7578               PX-  0  0  3  NS CTR PASSG              TOTAL HOURS, 102 IN TYPE,
                                       DAMAGE-SUBSTANTIAL  OT-  0  0  0                            INSTRUMENT RATED.
        NAME OF AIRPORT - RUSHMORE HELIPAD
        DEPARTURE POINT             INTENDED DESTINATION
          KEYSTONE,SD                 LOCAL
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           COLLIDED WITH: TREES                                     IN FLIGHT: UNCONTROLLED DESCENT
        PROBABLE CAUSE(S)
           PILOT IN COMMAND - FAILED TO MAINTAIN ADEQUATE ROTOR R.P.M.
           PILOT IN COMMAND - IMPROPER IN-FLIGHT DECISIONS OR PLANNING
           PILOT IN COMMAND - FAILED TO OBTAIN/MAINTAIN FLYING SPEED
           PILOT IN COMMAND - EXERCISED POOR JUDGMENT
        FACTOR(S)
           WEATHER - HIGH DENSITY ALTITUDE
        WEATHER BRIEFING - NO RECORD OF BRIEFING RECEIVED
        WEATHER FORECAST - UNKNOWN/NOT REPORTED
        SKY CONDITION                                            CEILING AT ACCIDENT SITE
          SCATTERED                                                 10000
        VISIBILITY AT ACCIDENT SITE                              PRECIPITATION AT ACCIDENT SITE
          5 OR OVER(UNLIMITED)                                     NONE
        OBSTRUCTIONS TO VISION AT ACCIDENT SITE                  TEMPERATURE-F
          NONE                                                      90
        TYPE OF WEATHER CONDITIONS                               TYPE OF FLIGHT PLAN
          VFR                                                      NONE
```

## Aircraft

- Registration: [N7578](https://openairdocs.org/aircraft/N7578), registered now, S/N 2674, built 1961 (OpenAirDocs)
- Reported make and model: BELL 47-G2A
- Registry model: [Bell 47G-2A](https://openairdocs.org/model/bell-47g-2a) (registry code 1181012) (OpenAirDocs)
- Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Engines: reciprocating
- Damage: Substantial damage
- Airport: Rushmore Helipad

## 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 19750725022909A](https://openairdocs.org/incident/19750725022909A), Jul 25, 1975: Bell 47G2A, Keystone, SD, Substantial damage

## Other investigations on N7578 (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 CEN11CA525](https://openairdocs.org/ntsb/CEN11CA525), Jul 27, 2011: Bell 47G-2A (N7578), Nicolett, MN, substantial damage. Probable cause: The pilot's failure to maintain control of the helicopter while maneuvering during an aerial application flight.
- [NTSB MKC78FER45](https://openairdocs.org/ntsb/MKC78FER45), May 17, 1978: Bell 47G-2A (N7578), Arden Hills, MN, 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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