# NTSB ANC72AA009: Sikorsky S-55B, Valdez, AK, August 12, 1971

- Type: NTSB accident investigation
- Date: August 12, 1971
- Place: Valdez, AK · VALDEZ, AK
- Location: 61.1308° N, 146.3483° W: Placed by OpenAirDocs: center of Valdez, AK, within about 8 miles (OpenAirDocs)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed
- Report: DirectorBrief, April 20, 1972
- NTSB case key (mKey): 162145
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC72AA009
- Page: https://openairdocs.org/ntsb/ANC72AA009

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-3388  71/8/12    VALDEZ,ALAS         SIKORSKY S-55B      CR-  1  0  0  COMMERCIAL                COMMERCIAL, AGE 28, 3893
        TIME - 1427                    N5096V              PX-  1  0  0  AIR TAXI-PASSG            TOTAL HOURS, 186 IN TYPE,
                                       DAMAGE-DESTROYED    OT-  0  0  0                            NOT INSTRUMENT RATED.
        NAME OF AIRPORT - VALDEZ
        DEPARTURE POINT             INTENDED DESTINATION
          VALDEZ,ALAS                 LOCAL
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           PROPELLER/ROTOR FAILURE: MAIN ROTOR                      IN FLIGHT: NORMAL CRUISE
           COLLISION WITH GROUND/WATER: UNCONTROLLED                IN FLIGHT: UNCONTROLLED DESCENT
        PROBABLE CAUSE(S)
           PERSONNEL - MAINTENANCE,SERVICING,INSPECTION: INADEQUATE MAINTENANCE AND INSPECTION
           ROTORCRAFT - TRANSMISSION ROTOR DRIVE SYSTEM: MAIN ROTOR GEAR BOX
           MISCELLANEOUS ACTS,CONDITIONS - BRITTLE
           MISCELLANEOUS ACTS,CONDITIONS - MATERIAL FAILURE
        FACTOR(S)
           MISCELLANEOUS ACTS,CONDITIONS - SEPARATION IN FLIGHT
         FIRE AFTER IMPACT
        REMARKS- IMPROPERLY HEAT TREATED PART INSTLD IN MAIN TSMN.VENDOR,SOURCE NOT IDENTD.TSMN,ROTOR HEAD SEPN.
```

## Sequence of events

- Enroute-cruise

## Aircraft

- Registration: N5096V, a cancelled registration (https://openairdocs.org/deregistered/N5096V-1972-11-15) (OpenAirDocs)
- Reported make and model: SIKORSKY S-55B
- Registry model: Sikorsky S-55B (registry code 8141604, https://openairdocs.org/model/sikorsky-s-55b) (OpenAirDocs)
- Category: Helicopter
- Damage: Destroyed
- Airport: VALDEZ

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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From OpenAirDocs.org, an independent open copy of NTSB and FAA data. The NTSB's own report is the official record of an investigation.