# NTSB LAX99LA288: Wirth Avid Flyer, N625F, Schellville, CA, August 29, 1999

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: August 28, 1999, 18:45 local (Aug 29, 1999, 01:45 UTC)
- Place: Schellville, CA
- Coordinates: 38.240791, -122.460716 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.2408&lon=-122.4607&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report August 14, 2001
- Report: Approved by Office Director
- NTSB case key (mKey): 47235
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX99LA288
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/47235/pdf
- Page: https://openairdocs.org/ntsb/LAX99LA288

## Probable cause

The pilot's encounter with wind shear and a downdraft which precipitated his loss of airplane control.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight encounter with weather, takeoff - initial climb
  - weather condition - windshear (cause)
  - aircraft control - attempted, pilot in command
- In flight collision with terrain/water, descent - uncontrolled
  - weather condition - downdraft (cause)
  - aircraft control - not maintained, pilot in command (cause)

## 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](https://openairdocs.org/deregistered/N625F-1999-11-23), registration cancelled 1999-11-23, S/N 625 (OpenAirDocs)
- Reported make and model: WIRTH AVID FLYER
- Registry model: [Wirth Richard AVID FLYER](https://openairdocs.org/model/wirth-richard-avid-flyer) (registry code 05616L9) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 625
- Airframe hours: 190
- Engines: 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

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; 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 (OpenAirDocs).

- [Accident 19990828043589A](https://openairdocs.org/incident/19990828043589A), Aug 28, 1999: Amtr AVIDFLYER, Schellville/Son, CA, No damage. (-23) Pilot experienced severe turbulence after take off at about 1500 ft. at this point pilot lost control of the a/c and collided with hilly terrain at about…

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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