# NTSB ANC76AA112: Bell 47G3B1, N7901S, Petersburg, AK, July 17, 1976

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Closed
- Date: July 17, 1976
- Place: Petersburg, AK · PETERSBURG, AK
- Location: 56.8113° N, 132.9513° W: Placed by OpenAirDocs: center of Petersburg, AK, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=56.8113&lon=-132.9513&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report March 1, 1977
- Report: Brief approved by the director
- NTSB case key (mKey): 155102
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC76AA112
- Page: https://openairdocs.org/ntsb/ANC76AA112

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-3890  76/7/17    PETERSBURG,AK       BELL 47G3B1         CR-  1  0  0  NONCOMMERCIAL             COMMERCIAL, AGE 29, 3700
        TIME - UNK/NR                  N7901S              PX-  1  0  0  PLEASURE/PERSONAL TRANSP  TOTAL HOURS, 600 IN TYPE,
                                       DAMAGE-DESTROYED    OT-  0  0  0                            NOT INSTRUMENT RATED.
        DEPARTURE POINT             INTENDED DESTINATION
          BIG JOHN BAY,AK             PETERSBURG,AK
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           PROPELLER/ROTOR FAILURE: TAIL ROTOR                      IN FLIGHT: OTHER
        PROBABLE CAUSE(S)
           PERSONNEL - MAINTENANCE,SERVICING,INSPECTION: INADEQUATE MAINTENANCE AND INSPECTION
           ROTORCRAFT - ROTOR ASSEMBLIES: TAIL ROTOR BLADES
           MISCELLANEOUS ACTS,CONDITIONS - FATIGUE FRACTURE
        FACTOR(S)
           MISCELLANEOUS ACTS,CONDITIONS - SEPARATION IN FLIGHT
         FIRE AFTER IMPACT
        REMARKS- T/R BLADES 22.1HRS PAST MANDATORY CHANGE TIME.
```

## Aircraft

- Registration: [N7901S](https://openairdocs.org/deregistered/N7901S-2018-01-09), registration cancelled 2018-01-09, S/N 6576 (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: Destroyed

## Other investigations on N7901S (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 FTW98TA099](https://openairdocs.org/ntsb/FTW98TA099), Jan 15, 1998: Bell 47G-3B-1 (N7901S), Magdalena, NM, substantial damage. Probable cause: The pilot's failure to maintain adequate main rotor rpm. A factor was a lack of recent experience in the type of operation being performed.
- [NTSB LAX80DUK06](https://openairdocs.org/ntsb/LAX80DUK06), Sep 24, 1980: Bell 47G3B1 (N7901S), Seligam, AZ, destroyed
- [NTSB OAK71DVA40](https://openairdocs.org/ntsb/OAK71DVA40), Nov 19, 1970: Bell 47G3B1 (N7901S), Grant Cove, CA, 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.

---
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.