What happened
During an approach to San Francisco Airport, a twin-engine aircraft encountered significantly reduced visibility caused by dense fog. While navigating the descent, the crew lowered the plane's altitude below the established minimum descent altitude (MDA). This maneuver led the aircraft to strike the surface of the San Francisco Bay a short distance from the shoreline.
Following the impact, the aircraft sank and was subsequently lost. All four occupants sustained injuries during the accident, but they were successfully rescued from the scene.
Findings
Investigations into the crash identified several contributing elements related to the flight's execution under instrument flight rules (IFR). The primary factor was improper IFR operation by the crew, who did not adhere to approved flight procedures. Additional contributing factors included:
- Descent below the authorized minimum descent altitude
- Weather conditions that were much more severe than what had been predicted
- Low cloud ceilings and heavy fog
- Insufficient preparation prior to the flight
- A request for runway or approach lighting identification that was not being provided by the operator