Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Oconomowoc, Wisconsin 53066
Sunday, November 21, 2004 14:30 CST
NTSB Narrative Summary Released at Completion of Accident
The amateur-built airplane was damaged during a forced landing following a loss of engine power during cruise flight. The propeller and hub separated in-flight as result of a crankshaft failure. The airplane impacted a small ditch during the forced landing that resulted in the airplane nosing-over. The experimental airplane was powered by a non-certified Volkswagen 2180cc engine that was modified for aircraft use. The engine crankshaft was fractured between the oil-slinger and the retaining snap-ring groves. The fracture initiated at the aft edge of the forward keyway. The fracture features were consistent with a fatigue-type failure. The propeller and hub were not recovered during the investigation. The pilot/builder reported that he had mistakenly installed the number four (aft-most) bearing at the number two position during initial assembly of the engine. He had to remove the shrink-fit propeller hub, drive gears and spacer in order to reinstall the bearings in the correct order. The pilot/builder reported that he did not check the dimensions of the shrink-fit components prior to reassembling the engine, nor did he consult with the engine kit manufacturer on how to disassemble, inspect, and reassemble the engine components. The engine kit manufacturer did not provide the builder with engine disassembly or overhaul instructions with delivery of the engine kit. The engine kit manufacturer did not instruct builders to verify the dimensions of the shrink-fit components prior to their installation. The experimental airframe and engine did not have to comply with federal regulations required for a standard category airplane. The engine and airframe had accumulated 45.3 hours since new.
NTSB Probable Cause Narrative
The loss of engine power due to a fatigue fracture of the crankshaft. An additional cause to the accident was the pilot/builder's failure to verify the dimensions of the shrink-fit crankshaft components prior reassembling the engine. A factor to the accident was the ditch encountered during the forced landing.
Event Information
| Type of Event | Accident |
| Event Date | 11/21/2004 |
| Event Day of the Week | Sunday |
| Time of Event | 1430 |
| Event Time Zone | Central Standard Time |
| Event City | Oconomowoc |
| Event State | WISCONSIN |
| Event Country | -- |
| Zipcode of the event site | 53066 |
| Event Date Year | 2004 |
| Event Date Month | 11 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 430634N |
| Event Location Longitude | 0882910W |
| 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 | 1435 Central Standard Time |
| Direction of event from weather observation facility (degrees) | 270 |
| Weather Observation Facility ID | RYV |
| Elevation of weather observation facility | 833 |
| Distance of event from weather observation facility (units?) | 11 |
| Time Zone of the weather observation | CST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | 8500 |
| Sky/Lowest/Cloud Conditions | Scattered |
| 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) | 6 |
| Dew Point at event time (in degress fahrenheit) | -3 |
| Wind Direction (degrees magnetic) | 240 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 6 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.3 |
| Density Altitude (feet) | -450 |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Serious |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | 1 |
| Injury Total All | 1 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 17276 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Nov 21 2004 12:00AM |
| NTSB Notification Time | 1653 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Feb 24 2005 9:13AM |
| User who most recently changed record | NTSB\JOHB |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Federal Aviation Administration - Milwaukee FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N478SX |
| NTSB Number | CHI05CA032 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Olson |
| Aircraft Model | Sonex |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 478SX |
| Certified Max Gross Weight | 1100 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | Yes |
| 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 | May 12 2004 12:00AM |
| Airframe hours since last inspection | 45.3 |
| Airframe Hours | 45.3 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Harold D. Olson |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | -- |
| Aircraft Owner State | -- |
| Aircraft Owner Country | -- |
| Aircraft Owner Zipcode | -- |
| Operator is an individual? | Yes |
| Operator Name | -- |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 1141 Yosemite Road |
| Operator City | Oconomowoc |
| Operator State | WI |
| Operator Country | USA |
| Operator Zip code | 53066 |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | -- |
| 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 | No |
| Departure Airport Code | RYV |
| Departure City | Watertown |
| Departure State | WI |
| Departure Country | USA |
| Departure Time | 1400 |
| Departure Time Zone | CST |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | RYV |
| Destination City | -- |
| Destination State | -- |
| Destination Country | -- |
| Specific Phase of Flight | Emergency descent/landing |
| Report sent to ICAO? | No |
| Evacuation occurred | No |
| Date of most recent change to record | -- |
| User who most recently changed record | -- |
| 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 | -- |