# NTSB SEA83FA009: Boeing Vertol 107, N6676D, Cascade, ID, October 14, 1982

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: October 14, 1982, 14:18 local (20:18 UTC)
- Place: Cascade, ID
- Coordinates: 44.589138, -115.570747 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.5891&lon=-115.5707&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report October 14, 1983
- Report: Approved by Office Director
- NTSB case key (mKey): 70154
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA83FA009
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/70154/pdf
- Page: https://openairdocs.org/ntsb/SEA83FA009

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, maneuvering
  - rotor drive system,engine to transmission drive - improper (cause)
  - inadequate quality control, production/design personnel (cause)
  - rotor drive system,engine to transmission drive - fatigue (cause)
  - rotor drive system,engine to transmission drive - failure,total (cause)
  - rotor drive system,engine to transmission drive - disabled (cause)
- Loss of control - in flight, maneuvering

## Analysis

DURING A LOG SLINGING OPERATION A LOUD BANG WAS HEARD & THE ACFT WAS OBSERVED TO RAPIDLY DESCEND VERTICALLY TO THE GROUND WITH NUMEROUS SMALL FRAGMENTS FALLING IN THE SAME VICINITY. THE #5 SYNCHRONIZATION SHAFT WAS FOUND TO BE FRACTURED AT THE FORWARD END ABOUT 9 INCHES AFT OF THE CONNECTION ASSY TO THE #4 SHAFT. THIS RESULTED IN AN OUT OF SYNCHRONIZATION CONDITION BETWEEN THE FORWARD & AFT ROTOR BLADES AS WELL AS A LOSS OF POWER TO THE FORWARD ROTOR. A FATIGUE FRACTURE ORIGINATED IN THE AFT MOST RING OF RIVET HOLES. THE FATIGUE CRACKS PROPOGATED FROM MULTIPLE ORIGINS WITHIN THOSE RIVET HOLES WHERE A "STEP" WAS FOUND AT THE BASE OF THE HOLE & CLOSEST TO THE INSIDE DIAMETER OF THE SHAFT.ALL RIVET HOLES IN THE FORWARD END OF THE SHAFT HAD TOPOGRAPHIC FEATURES SIMILAR TO THOSE PRODUCED IN A STEEL PLATE BY DELIBERATELY DRILLING HOLES WITHOUT COMPLETE PENETRATIONS.

## Aircraft

- Registration: [N6676D](https://openairdocs.org/aircraft/N6676D), registered now, S/N 6 (OpenAirDocs)
- Reported make and model: BOEING VERTOL 107
- Registry model: [Vertol 107-II](https://openairdocs.org/model/vertol-107-ii) (registry code 9420604) (OpenAirDocs)
- Registry engine: [GE T58 series](https://openairdocs.org/engine/ge-t58-series) (registry code 30008, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 6
- Airframe hours: 2343
- Engines: GE CT-58-140 1500 horsepower turbo shaft
- Damage: Destroyed
- Flight: Part 133
- Operator: Columbia Helicopters, Inc.
- Registered owner: Columbia Helicopters, Inc.
- Departed: CASCADE, ID
- Destination: CASCADE, ID

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; commercial; medical: class 2, valid medical--w/ waivers/lim; flight hours: 6,800 total, 4,300 in this make and model, 303 in the last 90 days, 80 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 30 statute miles
- Temperature: 156 °F
- Altimeter: 30.00 inHg

## 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 19821014052839A](https://openairdocs.org/incident/19821014052839A), Oct 14, 1982: Boeing 1072B, Cascade, ID, Destroyed. Sychronization shaft between rotors fractured at forward end during sling load operation. Main rotors collided.

## Other investigations on N6676D (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 SEA75DYC02](https://openairdocs.org/ntsb/SEA75DYC02), Jul 11, 1974: Vertol 107 (N6676D), Estacada, OR, no damage
- [NTSB NYC67A0129](https://openairdocs.org/ntsb/NYC67A0129), Mar 14, 1967: Vertol 107II (N6676D), Newark, NJ, substantial damage
- [NTSB NYC65I0111](https://openairdocs.org/ntsb/NYC65I0111), Feb 26, 1965: Vertol V-107 (N6676D), Brooklyn, NY, incident, no 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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