Preflight Briefing
The pilot received a preflight weather briefing and filed a VFR flight plan before departing Sacramento, California. During the briefing, the pilot was advised of forecast IFR conditions, with ceilings occasionally less than 1,000 feet and visibility of 3 miles. Airmets indicated mountain obscuration with scattered moderate to heavy rain. The flight service station briefer concluded that after 1900-2000, weather would reduce to marginal VFR flight conditions.
Departure from Sacramento
When the pilot opened his VFR flight plan by radio, the briefer again questioned whether he had the airmet for mountain obscuration, IFR conditions, and current route information. The pilot affirmed, and the briefer concluded by stating that VFR flight was not recommended.
Livermore Airport
After arriving at Livermore airport, the local controller asked if the pilot had a clearance on file or wished to file one before departing Livermore. The pilot declined.
Accident Site
The accident site was located between 1,900 and 2,000 feet mean sea level on a route consistent with a downwind departure from Livermore.
Weather Conditions
A weather study by the Safety Board indicated that the airplane most likely experienced light to moderate rain after takeoff, with heavy to very heavy rain near the accident site. Witnesses in the vicinity confirmed that it was raining heavily near the time of the accident.