Individually Owned: 151,845
Corporate Owned: 143,699
Aircraft Accident/Incident Report
Leavenworth, Washington 98826
Tuesady, November 5, 1996 14:00 PST
NTSB Narrative Summary Released at Completion of Accident
The pilot/operator, who had been utilizing the rotorcraft for heavy log lifting operations for the previous 18 months, was initiating a log lift cycle from a hover when the vertical stabilizer separated from the restricted category Garlick TH-1L. The rotorcraft subsequently descended out of control, impacting wooded, sloped terrain. Post-crash metallurgical examination discovered fatigue fractures emanating from a rivet hole within all five layers of the left side aluminum spar cap buildup for the vertical stabilizer. Additionally, fatigue cracking was observed within the tail boom skin near the vertical stabilizer and additional rivets were noted in both sides of the tail boom skin area. The tail boom skin crack was noted to have two separate stop holes drilled in its progression. Maintenance records showed no evidence of an inspection of the spar cap area or internal inspection of the tail cone or vertical fin at the time of installation of six blind rivets in the vertical fin, 18 months previous to the accident. No record was found recording the time of stop-drilling the skin crack progression. Examination of the riveted structure in the vicinity of the tailboom-to-vertical stabilizer junction revealed 30 blind rivets without paint on their exterior or interior ends on the left side of the vertical stabilizer, including seven that were directly adjacent to the separation point in the left cap of the stabilizer front spar. Four similar rivets were noted on the right side of the vertical stabilizer. Helicopter logging operations require repetitive high-stress/high-cycle operations.
NTSB Probable Cause Narrative
Fatigue failure of the vertical stabilizer spar cap and subsequent loss of the rotorcraft's vertical stabilizer. Factors include inadequate inspection or trouble-shooting of the aircraft tail cone and vertical stabilizer at and after the time sheet-metal skins were stop-drilled and rivets were replaced, and repetitive cycles associated with helicopter logging operations.
Event Information
| Type of Event | Accident |
| Event Date | 11/5/1996 |
| Event Day of the Week | Tuesday |
| Time of Event | 1400 |
| Event Time Zone | Pacific Standard Time |
| Event City | LEAVENWORTH |
| Event State | WASHINGTON |
| Event Country | -- |
| Zipcode of the event site | 98826 |
| Event Date Year | 1996 |
| Event Date Month | 11 |
| 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 | 1415 Pacific Standard Time |
| Direction of event from weather observation facility (degrees) | 132 |
| Weather Observation Facility ID | EAT |
| Elevation of weather observation facility | 1245 |
| Distance of event from weather observation facility (units?) | 29 |
| Time Zone of the weather observation | PST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 0 |
| Lowest Non-Ceiling Height | 9000 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | Unknown |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 9 |
| Dew Point at event time (in degress fahrenheit) | -3 |
| Wind Direction (degrees magnetic) | 0 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 0 |
| Wind Velocity Indicator | Calm |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 30 |
| 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 | 1 |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | 1 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 1913 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Nov 5 1996 12:00AM |
| NTSB Notification Time | 1535 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Aug 14 2001 3:23PM |
| User who most recently changed record | MONR |
| Basic weather conditions | Unknown |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N465JR |
| NTSB Number | SEA97LA025 |
| 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 | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Garlick |
| Aircraft Model | TH-1L |
| Aircraft Series Identifier | TH-1L |
| Aircraft Serial Number | 157828 |
| Certified Max Gross Weight | 9500 |
| 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 | 2 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Jan 19 1996 12:00AM |
| Airframe hours since last inspection | 311 |
| Airframe Hours | 8198 |
| ELT Installed | Unknown |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | WILLIAMS HELICOPTER CORP. |
| Aircraft Owner Street Address | 220A LAKEVIEW ROAD |
| Aircraft Owner City | OZARK |
| Aircraft Owner State | AL |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 36360 |
| Operator is an individual? | -- |
| Operator Name | KENNEDY, ROBIN |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | SE 121 EMERALD DRIVE |
| Operator City | SHELTON |
| Operator State | WA |
| Operator Country | |
| Operator Zip code | 98584 |
| Operator Code | C36L |
| 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 | 0 |
| Departure Time Zone | |
| 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 | -- |
| 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 | -- |