Arlington Municipal Airport
Aircraft Accident/Incident Report

Arlington, Washington 98223
Thursday, July 8, 2010 13:05 PDT

NTSB Narrative Summary Released at Completion of Accident

The pilot reported that after an uneventful flight, he entered a left downwind traffic pattern for his intended landing area. As he lowered the collective to initiate a descent, he immediately experienced a severe vibration. The pilot stated that the vibration was so violent that it was impossible to read the cockpit instruments. He raised and lowered the collective and noted no change in the vibration. The pilot then initiated an autorotation to an open field adjacent to his intended landing area. The helicopter landed hard and came to rest upright. A postaccident examination of the helicopter revealed that the tail rotor was separated from the tail boom with additional damage observed to the fuselage and main rotor blades. Flight control continuity was established throughout the helicopter's flight control system. The source of the vibration could not be determined.

NTSB Probable Cause Narrative

An undetermined airframe vibration which led to precautionary autorotation and hard landing.

Event Information

Type of Event Accident
Event Date 7/8/2010
Event Day of the Week Thursday
Time of Event 1305
Event Time Zone Pacific Daylight Time
Event City Arlington
Event State WASHINGTON
Event Country --
Zipcode of the event site 98223
Event Date Year 2010
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 480938N
Event Location Longitude 1220932W
Event Location Airport Arlington Municipal
Event Location Nearest Airport ID AWO
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles 0
Degrees magnetic from airport --
Airport Elevation 142
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 AWO
Elevation of weather observation facility 142
Distance of event from weather observation facility (units?) 0
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) 29
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 290
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 5
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) --
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) 28003
NTSB Notification Source FAA NW Operations Center
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Jan 18 2011 8:57PM
User who most recently changed record stam
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N62AJ
NTSB Number WPR10LA336
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name JOHNSON
Aircraft Model HELICYCLE
Aircraft Series Identifier --
Aircraft Serial Number 3-24
Certified Max Gross Weight 850
Aircraft Category Helicopter
Aircraft Registration Class --
Aircraft is a homebuilt? Yes
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 Continuous Airworthiness
Date of Last Inspection Jun 4 2010 12:00AM
Airframe hours since last inspection 1
Airframe Hours 123
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type Unknown
Aircraft Owner Name JOHNSON ALDEN B
Aircraft Owner Street Address --
Aircraft Owner City PORT LUDLOW
Aircraft Owner State WA
Aircraft Owner Country USA
Aircraft Owner Zipcode 98365-9420
Operator is an individual? No
Operator Name JOHNSON ALDEN B
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City PORT LUDLOW
Operator State WA
Operator Country USA
Operator Zip code 98365-9420
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation --
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) Personal
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code AWO
Departure City Arlington
Departure State WA
Departure Country USA
Departure Time 1300
Departure Time Zone PDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code AWO
Destination City Arlington
Destination State WA
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 14 2011 7:29PM
User who most recently changed record stam
Since inspection or accident Time of Accident
Event Location Runway Number and Location 29
Runway Length 3498
Runway Width 75
Sight Seeing flight No
Air Medical Flight No
Medical Flight --