| Date: | Wednesday 12 September 1951 |
| Time: | 10:46 |
| Type: |  Boeing 377 Stratocruiser 10-34 |
| Owner/operator: | United Airlines |
| Registration: | N31230 |
| MSN: | 15970/61 |
| Year of manufacture: | 1949 |
| Total airframe hrs: | 1971 hours |
| Engine model: | Pratt & Whitney R-4360-B6 |
| Fatalities: | Fatalities: 3 / Occupants: 3 |
| Other fatalities: | 0 |
| Aircraft damage: | Destroyed, written off |
| Category: | Accident |
| Location: | off Redwood City, CA -
 United States of America
|
| Phase: | Approach |
| Nature: | Training |
| Departure airport: | San Francisco International Airport, CA (SFO/KSFO) |
| San Francisco International Airport, CA (SFO/KSFO) | |
| Investigating agency: | CAB |
| Confidence Rating: |  Accident investigation report completed and information captured |
United Air Lines' Boeing Stratocruiser "Mainliner Oahu" was being used for a semi-annual instrument check of a captain. In addition, consideration had been given to investigating the feasibility of using the Oakland, California, Municipal Airport for certain phases of crew training in this type aircraft for a new class of pilots and flight engineers which was to convene that afternoon. The flight departed at 09:42 and reported on top of the broken scattered clouds four minutes later. The flight proceeded to Oakland, where a simulated ILS approach was carried out, followed by a missed approach procedure. The flight again reported on top at 10:36. Another simulated ILS approach was requested of the Oakland tower but the flight was advised that there would be a delay due to other traffic. In view of this, the pilot decided to return to San Francisco. At 10:39, the flight was cleared for an ILS approach to the San Francisco Airport. The aircraft, with No. 4 propeller feathered, stalled and abruptly dived from an altitude of approximately 300 feet and was demolished upon impact in San Francisco Bay.
PROBABLE CAUSE: "An inadvertent stall at a low altitude from which recovery was not effected."
Accident investigation:
 |
|
Sources:
CAB File No. 1-0089
Location
Revision history:
| Date/time | Contributor | Updates |
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