Aircraft Accident/Incident Report

Monmouth, Oregon 97361
Tuesady, March 6, 2007 11:00 PST

NTSB Narrative Summary Released at Completion of Accident

The pilot reported that he was spraying Christmas trees, when the engine experienced an over speed condition and he "lost all power to the transmission." The pilot initiated a forced landing to a field. During the forced landing, the helicopter touched down hard and bent the tail boom. The pilot stated that the engine was producing power, but it wasn't being delivered to the rotor blades. Examination of the helicopter revealed the shaft of the main drive belt tension assembly was fractured, which resulted in the main drive belt disengaging from the transmission. Materials examination of the shaft showed that the shaft fractured due to high cycle, low stress fatigue. The fatigue initiated from multiple origins at the thread root. No material defects specific to the origin were noted, but overall hardness values suggested that the shaft strength was less than typical strength values for the specified material. It remained undetermined whether the strength was above the design minimum since no material specifications for the shaft could be produced by the manufacturer.

NTSB Probable Cause Narrative

The failure of the main drive belt tension assembly shaft due to high cycle, low stress fatigue.

Event Information

Type of Event Accident
Event Date 3/6/2007
Event Day of the Week Tuesday
Time of Event 1100
Event Time Zone Pacific Standard Time
Event City Monmouth
Event State OREGON
Event Country --
Zipcode of the event site 97361
Event Date Year 2007
Event Date Month 3
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 440500N
Event Location Longitude 1230000W
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) 12
Dew Point at event time (in degress fahrenheit) 7
Wind Direction (degrees magnetic) 180
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 3
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.1
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 24001
NTSB Notification Source FAA
NTSB Notification Date Mar 12 2007 12:00AM
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Jul 30 2008 9:00AM
User who most recently changed record NTSB\johb
Basic weather conditions Visual Meteorological Cond
FAA District Office Portland, OR FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N785M
NTSB Number LAX07LA106
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 137: Agricultural
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Enstrom
Aircraft Model F-28F
Aircraft Series Identifier --
Aircraft Serial Number 785
Certified Max Gross Weight 2600
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 3
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Jan 1 2007 12:00AM
Airframe hours since last inspection --
Airframe Hours 2393.2
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name Louis A. Fusco
Aircraft Owner Street Address --
Aircraft Owner City Newport
Aircraft Owner State OR
Aircraft Owner Country USA
Aircraft Owner Zipcode 97365
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 KWQL
Owner has at least one certificate --
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation Agriculture
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) Aerial Application
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code --
Departure City Monmouth
Departure State OR
Departure Country USA
Departure Time 1050
Departure Time Zone PST
Destination Same as Local Flt --
Destination Airport Code --
Destination City Corvalis
Destination State OR
Destination Country USA
Specific Phase of Flight Maneuvering - aerial application
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jul 22 2008 4:39PM
User who most recently changed record COOS
Since inspection or accident Time of Accident
Event Location Runway Number and Location NA
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --