| Crash location | Unknown |
| Nearest city | Hayward, CA
37.668821°N, 122.080796°W |
| Tail number | N9721B |
|---|---|
| Accident date | 15 Jan 1991 |
| Aircraft type | Cessna 172RG |
| Additional details: | None |
THE PILOT'S FAILURE TO MAINTAIN ALTITUDE. CONTRIBUTING FACTORS RELATED TO THE PILOT'S IMPROPER VFR PROCEDURES AND HIS MISJUDGED EVALUATION OF THE WEATHER IN DAYLIGHT CONDITIONS. ADDITIONAL FACTORS RELATED TO THE PRESENCE OF LOW CLOUDS AND TO THE RESTRICTED VISIBILITY.