- Date
- August 28, 1999, 18:45 local (Aug 29, 1999, 01:45 UTC)
- Place
- Schellville, CA
- Injuries
- 1 minor
- Damage
- Destroyed
- Phase of flight
- Initial climb
- Aircraft
- N625FWirth Avid Flyer
- Weather
- Visual (VMC) · Day
- Status
- Completed · report August 14, 2001
- Report
- Approved by Office Director
- FAA report
- 19990828043589A
- Case key
- 47235
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The pilot's encounter with wind shear and a downdraft which precipitated his loss of airplane control.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
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.
Factual narrative
On August 28, 1999, about 1845 hours Pacific daylight time, an experimental Richard Wirth Avid Flyer, N625F, registered to and operated by the pilot, encountered wind shear during initial climb from the uncontrolled Sonoma Valley Airport, Schellville, California. Thereafter, the homebuilt airplane descended into terrain and was substantially damaged. Visual meteorological conditions prevailed during the personal flight in the experimental category airplane. The flight was being performed under 14 CFR Part 91. The private pilot received minor injuries. The flight was originating at the time of the accident.
According to the pilot, he took off under calm wind conditions. However, he encountered a wind shear upon climbing 50 to 75 feet above the ground. The pilot further reported that the wind was strong enough to yaw his airplane 15 degrees, and it appeared to push him backwards. Control was lost, and the airplane descended until impacting a ditch about 200 feet from the runway. No mechanical problems were experienced with the airplane during the flight.
Aircraft
- Registration
- N625F
- Reported as
- Wirth Avid Flyer
- Category
- Airplane, amateur-built
- Serial number
- 625
- Airframe hours
- 190
- Engine
- Rotax 582, 65 horsepower, reciprocating
- Damage
- Destroyed
- Flight
- Personal · Part 91
- Registered owner
- Jeffrey Wemmering
- Airworthiness certificate
- Special, Experimental (Special)
- Last inspection
- Annual · April 10, 1999 · 12 hours before
- Departed
- 0Q3 · CA
- Destination
- O69 · Petaluma, CA
- Airport
- 0Q3 · Sonoma Valley, runway 25, 2,700 × 45 ft, asphalt
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 39
- Certificate
- Private
- Airplane ratings
- Single-engine land, Single-engine sea
- Medical
- Class 3, Valid Medical--no waivers/lim.
- Seat
- Left
- Flight hours
- 350 total · 60 in this make and model · 300 as pilot in command · 15 in the last 90 days · 10 in the last 30 days · 3 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 180° at 9 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 72 °F, dew point 61 °F
- Altimeter
- 29.00 inHg
- Observed at
- APC, 4 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.