Individually Owned: 150,657
Corporate Owned: 137,281
Sonoma Valley Airport
Aircraft Accident/Incident Report
Schellville, California 95476
Saturday, August 28, 1999 18:45 PDT
NTSB Narrative Summary Released at Completion of Accident
The pilot, in his experimental 65 hp, 1,200-pound gross weight airplane, took off under calm wind conditions and gained 50 to 75 feet. Then, a wind shear was encountered which yawed the airplane 15 degrees, and the airplane appeared to be pushed backwards. The pilot lost control, and the airplane descended until impacting a ditch about 200 feet from the runway.
NTSB Probable Cause Narrative
The pilot's encounter with wind shear and a downdraft which precipitated his loss of airplane control.
Event Information
| Type of Event | Accident |
| Event Date | 8/28/1999 |
| Event Day of the Week | Saturday |
| Time of Event | 1845 |
| Event Time Zone | Pacific Daylight Time |
| Event City | SCHELLVILLE |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 95476 |
| Event Date Year | 1999 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| Event Location Airport | SONOMA VALLEY |
| Event Location Nearest Airport ID | 0Q3 |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 1 |
| Degrees magnetic from airport | 250 |
| Airport Elevation | 10 |
| Weather Briefing Completeness | Not pertinent |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1854 Pacific Daylight Time |
| Direction of event from weather observation facility (degrees) | 80 |
| Weather Observation Facility ID | APC |
| Elevation of weather observation facility | 33 |
| Distance of event from weather observation facility (units?) | 4 |
| Time Zone of the weather observation | PDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 0 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| 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) | 22 |
| Dew Point at event time (in degress fahrenheit) | 16 |
| Wind Direction (degrees magnetic) | 180 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 9 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 29 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| 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) | 1725 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Aug 29 1999 12:00AM |
| NTSB Notification Time | 1300 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Aug 14 2001 1:52PM |
| User who most recently changed record | MONR |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N625F |
| NTSB Number | LAX99LA288 |
| 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 | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | WIRTH |
| Aircraft Model | AVID FLYER |
| Aircraft Series Identifier | AVID FLYER |
| Aircraft Serial Number | 625 |
| Certified Max Gross Weight | 1200 |
| 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 | Apr 10 1999 12:00AM |
| Airframe hours since last inspection | 12 |
| Airframe Hours | 190 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | JEFFREY WEMMERING |
| Aircraft Owner Street Address | 401 CUTAH DRIVE |
| Aircraft Owner City | PETALUMA |
| Aircraft Owner State | CA |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 94952 |
| Operator is an individual? | -- |
| Operator Name | |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 401-C UTAH DRIVE |
| Operator City | PETALUMA |
| Operator State | CA |
| Operator Country | |
| Operator Zip code | 94952 |
| Operator Code | |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| 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 | 0Q3 |
| Departure City | |
| Departure State | CA |
| Departure Country | |
| Departure Time | 1840 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | O69 |
| Destination City | PETALUMA |
| Destination State | CA |
| Destination Country | |
| Specific Phase of Flight | Takeoff |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jan 14 2001 10:25AM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 25 |
| Runway Length | 2700 |
| Runway Width | 45 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |