Aircraft Accident/Incident Report

Canby, Oregon 97013
Friday, October 4, 1996 12:15 PDT

NTSB Narrative Summary Released at Completion of Accident

The Boeing Model BV-107-II departed on a maintenance check flight with 1.4 hrs total flight time after conversion from a Model HKP-4 per FAA Project #TDO639NY-R. About 37 min later, witnesses saw the rotorcraft moving erratically & tumbling out of control. Postcrash exam of the rotorcraft's flight control system revealed a disconnect between the lower bearing end of the aft directional and lateral control pushrod & the inboard clevis of the forward mixing unit section bellcrank. A bolt, consistent with hardware for that connection, was found in the control closet area. An improper part (collective bellcrank, PN 107C2606-8) was found in place of the required lateral bellcrank (PN 107C2606-9). Clevis width of the -8 part was slightly larger than the -9 part; thus, the clevis bolt was not long enough to allow a cotter pin to be properly installed through the nut & bolt with the required washers (2 thick & 1 thin) installed. To compensate (allow for installation of the cotter pin), 2 thin washers were used in place of the 2 thick and 1 thin washers. Metallurgical exam of the bolt revealed evidence that a nut had been applied to the threaded end, but there was no evidence that a cotter pin had been inserted. No pre-accident engine malfunction or crew impairment was evident.

NTSB Probable Cause Narrative

failure of maintenance personnel to install a cotter pin in a clevis bolt in the flight control system, which resulted in the aft directional and lateral control output pushrod to become disconnected from a bellcrank in the forward portion of the first stage mixing unit. A factor relating to the accident was the use of an improper bellcrank, which was wider in the clevis area.

Event Information

Type of Event Accident
Event Date 10/4/1996
Event Day of the Week Friday
Time of Event 1215
Event Time Zone Pacific Daylight Time
Event City CANBY
Event State OREGON
Event Country --
Zipcode of the event site 97013
Event Date Year 1996
Event Date Month 10
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 1247 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 279
Weather Observation Facility ID UAO
Elevation of weather observation facility 196
Distance of event from weather observation facility (units?) 3
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 4500
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 40
Air Temperature at event time (in degrees celsius) 24
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 170
Variable Wind Indicator Unknown
Wind Speed (knots) 14
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 18
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
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 3
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 3
Investigating Agency NTSB
NTSB Docket Number (internal use) 1809
NTSB Notification Source --
NTSB Notification Date Oct 4 1996 12:00AM
NTSB Notification Time 1254
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 10:25AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N196CH
NTSB Number SEA97FA001
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire Ground
Aircraft Explosion None
Aircraft Manufacturer's Full Name BOEING VERTOL
Aircraft Model BV-107 II
Aircraft Series Identifier BV-107 II
Aircraft Serial Number 407
Certified Max Gross Weight 20000
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 3
Number of Engines 2
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Unknown
Date of Last Inspection Oct 2 1996 12:00AM
Airframe hours since last inspection 2
Airframe Hours 7075
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name COLUMBIA HELICOPTERS, INC.
Aircraft Owner Street Address PO BOX 3500
Aircraft Owner City PORTLAND
Aircraft Owner State OR
Aircraft Owner Country
Aircraft Owner Zipcode 97208
Operator is an individual? --
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 CHIL
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 --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code 3S2
Departure City AURORA
Departure State OR
Departure Country
Departure Time 1138
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 Descent - uncontrolled
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:30AM
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 --