Accident Overview
During an approach to San Francisco Airport under foggy conditions, the flight crew of a twin-engine airplane descended below the minimum descent altitude (MDA). The aircraft subsequently struck the water surface and crashed into San Francisco Bay, just a few hundred yards offshore. All four occupants sustained injuries but were rescued; the aircraft sank and was lost.
Environmental Conditions
At the time of the accident, visibility was reduced due to fog. The weather conditions were considerably worse than forecast, with low ceilings and fog reported as contributing factors.
Operational Details
The aircraft was operating under instrument flight rules (IFR). The crew had inadequate preflight preparation, and they descended below the minimum descent altitude without proper adherence to approved procedures. Additionally, the operator's procedure requiring identification of approach or runway lights was not in effect.
Investigation Findings
Official investigation determined the probable cause to be improper IFR operation on the part of the crew, who failed to follow approved procedures. The following factors were reported: low ceiling and fog, inadequate preflight preparation, weather considerably worse than forecast, descent below MDA, and the operator's procedure for identification of approach or runway lights not being in effect.