# NTSB DEN66A0074: Bell 47G-3B, N73909, Grand Canyon, AZ, April 12, 1966

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Closed
- Date: April 12, 1966
- Place: Grand Canyon, AZ · GRAND CANYON, AZ
- Location: 36.0544° N, 112.1393° W: Placed by OpenAirDocs: center of Grand Canyon, AZ, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=36.0544&lon=-112.1393&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal, 2 serious
- Status: Completed, report February 15, 1967
- Report: Brief approved by the director
- NTSB case key (mKey): 172490
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN66A0074
- Page: https://openairdocs.org/ntsb/DEN66A0074

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
2-0602  66/4/12    UNKNOWN/NOT REPORTEDBELL 47G-3B         CR-  1  0  0  NONCOMMERCIAL             COMMERCIAL, AGE 47, 6916
        TIME - 0730                    N73909              PX-  0  2  0  CORP/EXEC                 TOTAL HOURS, 1381 IN
                                       DAMAGE-DESTROYED    OT-  0  0  0                            TYPE, INSTRUMENT RATED.
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           PROPELLER/ROTOR FAILURE: TAIL ROTOR                      TAKEOFF: INITIAL CLIMB
           COLLISION WITH GROUND/WATER: UNCONTROLLED                IN FLIGHT: UNCONTROLLED DESCENT
        PROBABLE CAUSE(S)
           ROTORCRAFT - TRANSMISSION ROTOR DRIVE SYSTEM: TAIL ROTOR GEAR BOX
           MISCELLANEOUS ACTS,CONDITIONS - MATERIAL FAILURE
           MISCELLANEOUS ACTS,CONDITIONS - JAMMED
           MISCELLANEOUS ACTS,CONDITIONS - IMPROPERLY INSTALLED
           PERSONNEL - MAINTENANCE,SERVICING,INSPECTION: INADEQUATE MAINTENANCE AND INSPECTION
        EMERGENCY CIRCUMSTANCES - FORCED LANDING OFF AIRPORT ON LAND
                                  DIRECTIONAL CONTROL PROBLEM
                                  SUSPECTED OR KNOWN AIRCRAFT DAMAGE
         FIRE AFTER IMPACT
        REMARKS- ROLLER BEARING RETAINER RING MISSING.SPACER AND WASHER REVERSD ON PINION SHAFT.GEAR BOX 103 HR SOH
```

## Aircraft

- Registration: [N73909](https://openairdocs.org/aircraft/N73909), registered now, S/N 2797, built 1962 (OpenAirDocs)
- Reported make and model: BELL 47G-3B
- Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (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: Destroyed

## Other investigations on N73909 (6)

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 SEA04LA114](https://openairdocs.org/ntsb/SEA04LA114), Jun 23, 2004: Bell 47G-3B-1 (N73909), Medford, OR, substantial damage. Probable cause: The pilot's failure to maintain clearance from a tree while maneuvering. Trees were a factor.
- [NTSB SEA94LA065](https://openairdocs.org/ntsb/SEA94LA065), Feb 24, 1994: Bell 47G-3B-1 (N73909), Gold Hill, OR, destroyed. Probable cause: SEPARATION OF THE CROSSOVER FUEL LINE, AND THE INABILITY OF THE PILOT IN COMMAND TO MAINTAIN A PROPER RATE OF DESCENT DURING THE AUTOROTATION.
- [NTSB SEA74DYA12](https://openairdocs.org/ntsb/SEA74DYA12), Oct 2, 1973: Bell 47G-3B (N73909), New Meadows, ID, destroyed
- [NTSB LAX70A0008](https://openairdocs.org/ntsb/LAX70A0008), Jul 30, 1969: Bell 47G3B1 (N73909), Grnd Canyon, AZ, destroyed, 3 fatal
- [NTSB LAX69D0357](https://openairdocs.org/ntsb/LAX69D0357), May 21, 1969: Bell 47G3B1 (N73909), Grnd Canyon, AZ, substantial damage
- [NTSB UNK64X0473](https://openairdocs.org/ntsb/UNK64X0473), Feb 5, 1964: Bell 47G3B1 (N73909), Little Nway, CA, destroyed, 1 fatal

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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