# NTSB DEN75FTE21: Bell 47G3B1, N1135W, Grand Valley, CO, September 6, 1974

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Closed
- Date: September 6, 1974
- Place: Grand Valley, CO · GRAND VALLEY, CO
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report November 14, 1974
- Report: Brief approved by the director
- NTSB case key (mKey): 138764
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN75FTE21
- Page: https://openairdocs.org/ntsb/DEN75FTE21

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-3319   74/9/6  NR.GRAND VALLEY,COLO  BELL 47G3B1         CR-  0  0  1  NONCOMMERCIAL             COMMERCIAL, FL.INSTR.,
        TIME - 0730                    N1135W              PX-  0  0  0  PLEASURE/PERSONAL TRANSP  AGE 52, 11500 TOTAL
                                       DAMAGE-SUBSTANTIAL  OT-  0  0  0                            HOURS, 4700 IN TYPE, NOT
                                                                                                   INSTRUMENT RATED.
        NAME OF AIRPORT - PRIVATE HELI PAD
        DEPARTURE POINT             INTENDED DESTINATION
         GRAND VALLEY,COLO            MONTROSE,COLO
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           MISCELLANEOUS                                            TAKEOFF: VERTICAL
           COLLISION WITH GROUND/WATER: CONTROLLED                  LANDING: LEVEL OFF/TOUCHDOWN
        PROBABLE CAUSE(S)
           ROTORCRAFT - TRANSMISSION ROTOR DRIVE SYSTEM: CLUTCH ASSEMBLY
           MISCELLANEOUS ACTS,CONDITIONS - EXCESSIVE-WEAR/PLAY
           PERSONNEL - MAINTENANCE,SERVICING,INSPECTION: INADEQUATE MAINTENANCE AND INSPECTION
        EMERGENCY CIRCUMSTANCES - FORCED LANDING ON AIRPORT/SEAPLANE BASE/HELIPT.
        REMARKS- TOO LOW FOR AUTOROTATION.CLUTCH LINING EXCESSIVLY WORN.NO OIL IN TANK.
```

## Aircraft

- Registration: [N1135W](https://openairdocs.org/deregistered/N1135W-1981-06-06), registration cancelled 1981-06-06, S/N 2932 (OpenAirDocs)
- Reported make and model: BELL 47G3B1
- Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (OpenAirDocs)
- Category: Helicopter
- Engines: reciprocating
- Damage: Substantial damage
- Airport: Private Heli Pad

## 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 19740906032879A](https://openairdocs.org/incident/19740906032879A), Sep 6, 1974: Bell 47G3B1, Grand Valley, CO, Destroyed. Too low for autorotation. Clutch lining excessivly worn. No oil in tank.

## Other investigations on N1135W (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 LAX78FA074](https://openairdocs.org/ntsb/LAX78FA074-139414), Sep 3, 1978: Bell 47G-3B (N1135W), Pasadena, CA, destroyed, 1 fatal
- [NTSB SEA74DYG44](https://openairdocs.org/ntsb/SEA74DYG44), Jun 4, 1974: Bell 47G3B1 (N1135W), Stratford, WA, destroyed
- [NTSB DEN66A0020](https://openairdocs.org/ntsb/DEN66A0020), Sep 9, 1965: Bell 47G3B1 (N1135W), Commerce Cty, CO, 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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