Aircraft Accident/Incident Report

Anatone, Washington 99401
Wednesday, May 12, 1993 7:15 PDT

NTSB Narrative Summary Released at Completion of Accident

THE CONVERTED MILITARY HELICOPTER WAS IN A HOVER LIFTING AN EXTERNAL LOAD OF LOGS WHEN THE MAIN ROTOR PYLONS SEPARATED IN FLIGHT, RESULTING IN AN UNCONTROLLED INVERTED DESCENT INTO THE GROUND. ON-SCENE EXAMINATION REVEALED THAT THE TRANSMISSION ROTOR INPUT GEAR SHAFT, P/N K774515-5F, HAD FRACTURED. SAFETY BOARD METALLURGICAL EXAMINATION SHOWED THAT THE FRACTURE WAS CHARACTERISTIC OF FATIGUE FAILURE, AND INDICATED REPETITIVE HIGH LOADS. THE FAA TYPE-CERTIFICATE, BASED ON MILITARY CONFIGURATION, LISTS THE APPROVED ENGINE AS 1100 SHP, AND THE EXTERNAL LOAD LIMIT AS 2,300 LBS. THE FAA HAD APPROVED INSTALLATION OF A 1400 SHP ENGINE, AND OPERATIONS WITH AN INCREASED EXTERNAL LOAD LIMIT OF 4,000 LBS.

NTSB Probable Cause Narrative

FATIGUE FAILURE OF THE ROTOR TRANSMISSION DRIVE SYSTEM, RESULTING FROM THE IMPROPER CERTIFICATION/APPROVAL OF THE AIRCRAFT MODIFICATION BY THE FEDERAL AVIATION ADMINISTRATION.

Event Information

Type of Event Accident
Event Date 5/12/1993
Event Day of the Week Wednesday
Time of Event 715
Event Time Zone Pacific Daylight Time
Event City ANATONE
Event State WASHINGTON
Event Country --
Zipcode of the event site 99401
Event Date Year 1993
Event Date Month 5
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 748 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 10
Weather Observation Facility ID LWS
Elevation of weather observation facility 1438
Distance of event from weather observation facility (units?) 26
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 30
Air Temperature at event time (in degrees celsius) 18
Dew Point at event time (in degress fahrenheit) 8
Wind Direction (degrees magnetic) 130
Variable Wind Indicator Unknown
Wind Speed (knots) 8
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) 4220
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Fatal
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal 1
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 721
NTSB Notification Source --
NTSB Notification Date May 12 1993 12:00AM
NTSB Notification Time 809
Fiche Number and/or location -used to find docket information 50380
Date of most recent change to record Dec 11 2000 1:20PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N846D
NTSB Number SEA93LA105
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 133: Rotorcraft Ext. Load
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire Ground
Aircraft Explosion None
Aircraft Manufacturer's Full Name KAMAN
Aircraft Model HH-43F
Aircraft Series Identifier HH-43F
Aircraft Serial Number 58-1846
Certified Max Gross Weight 9150
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 6
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Apr 27 1993 12:00AM
Airframe hours since last inspection 42
Airframe Hours 7266
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name ROBERT & SHARON WOODY
Aircraft Owner Street Address 63210 MCKENZIE LANE
Aircraft Owner City SUMMERVILLE
Aircraft Owner State OR
Aircraft Owner Country
Aircraft Owner Zipcode 97876
Operator is an individual? --
Operator Name WOODY CONTRACTING, INC
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address 63210 MCKENZIE LANE
Operator City SUMMERVILLE
Operator State OR
Operator Country
Operator Zip code 97876
Operator Code OWVL
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation External Load
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Unknown
Indicates Domestic or International Flight Unknown
Operator carrying Pax/Cargo/Mail Unknown
Type of Flying (Per_Bus / Primary) Other Work Use
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 700
Departure Time Zone PDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Hover
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --