Aircraft Accident/Incident Report

Dexter, Oregon 9734
Sunday, March 12, 2006 11:00 PST

NTSB Narrative Summary Released at Completion of Accident

While approaching the collection point with a load of logs, the helicopter's power turbine and rotor system experienced a steady-state overspeed due to the failure of the splines on the shaft that provides turbine speed input to the turbine governor. Without this input, the governor erroneously sensed a turbine underspeed, and therefore provided fuel in excess of that required to maintain the correct speed. The splines failed due to a significant reduction in the flow of lubricating oil resulting from the partial blockage of an oil filter outflow orifice. The outflow orifice became partially blocked because the oil filter screen was aligned in its housing in a manner that allowed some contaminants to bypass it. Although the Kaman K-1200 Flight Manual contains an emergency procedure that allows for the pilot to take manual (non-governed) control of the fuel input to the engine in the event of a governor failure, the pilot did not perform the procedure because he was not able to correctly identify the cause of the sequence of events.

NTSB Probable Cause Narrative

The pilot's failure to identify the overspeed of the helicopter's main rotors due to a turbine governor malfunction, and his failure to take the appropriate actions described in the Flight Manual's emergency procedures section. Factors include the malfunction (partial bypass) of a lubricating system filter screen, which led to the partial blockage of an oil supply orifice, resulting in the failure of the splines on the power turbine governor speed input shaft, and ultimately to the loss of the governor's ability to correctly control fuel input to the engine. Additional factors include no suitable landing terrain and tree stumps in the area the pilot elected to land in.

Event Information

Type of Event Accident
Event Date 3/12/2006
Event Day of the Week Sunday
Time of Event 1100
Event Time Zone Pacific Standard Time
Event City Dexter
Event State OREGON
Event Country --
Zipcode of the event site 9734
Event Date Year 2006
Event Date Month 3
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 434746N
Event Location Longitude 1224651W
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 --
Investigator's weather source Pilot
Time of the weather observation
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID --
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation --
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 2
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) --
Variable Wind Indicator --
Wind Speed (knots) --
Wind Velocity Indicator Calm
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.04
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor 1
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 21122
NTSB Notification Source FAA Operations Center
NTSB Notification Date Mar 12 2006 12:00AM
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Mar 26 2007 9:33AM
User who most recently changed record NTSB\lema
Basic weather conditions Visual Meteorological Cond
FAA District Office Portland FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N133KA
NTSB Number SEA06LA065
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 133: Rotorcraft Ext. Load
Type of Flight Plan filed None
Flight plan Was Activated? No
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Kaman
Aircraft Model K-1200
Aircraft Series Identifier --
Aircraft Serial Number 0005
Certified Max Gross Weight 12000
Aircraft Category Helicopter
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 1
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection AAIP
Date of Last Inspection Mar 1 2006 12:00AM
Airframe hours since last inspection 13
Airframe Hours 12675
ELT Installed No
ELT Activated --
ELT Aided Location of Event Site --
ELT Type --
Aircraft Owner Name Grizzly Mt. Aviation
Aircraft Owner Street Address 4411 NW Elliott Lane
Aircraft Owner City Prineville
Aircraft Owner State OR
Aircraft Owner Country USA
Aircraft Owner Zipcode 97754
Operator is an individual? No
Operator Name --
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City --
Operator State --
Operator Country --
Operator Zip code --
Operator Code --
Owner has at least one certificate --
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation External Load
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) External Load
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code --
Departure City Dexter
Departure State OR
Departure Country USA
Departure Time 1040
Departure Time Zone PST
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 Maneuvering
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Dec 31 2006 9:35PM
User who most recently changed record STAM
Since inspection or accident --
Event Location Runway Number and Location --
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --