Last updated: 5 April 2020
| Status: | Final |
| Date: | Wednesday 12 September 1951 |
| Time: | 10:46 |
| Type: | Boeing 377 Stratocruiser 10-34 |
| Operator: | United Airlines |
| Registration: | N31230 |
| C/n / msn: | 15970/61 |
| First flight: | 1949-12-19 (1 year 9 months) |
| Total airframe hrs: | 1971 |
| Engines: | 4 Pratt & Whitney R-4360-B6 |
| Crew: | Fatalities: 3 / Occupants: 3 |
| Passengers: | Fatalities: 0 / Occupants: 0 |
| Total: | Fatalities: 3 / Occupants: 3 |
| Aircraft damage: | Damaged beyond repair |
| Location: | off Redwood City, CA ( United States of America)
|
| Phase: | Approach (APR) |
| Nature: | Training |
| Departure airport: | San Francisco International Airport, CA (SFO/KSFO), United States of America |
| San Francisco International Airport, CA (SFO/KSFO), United States of America | |
| Flightnumber: | 7030 |
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:
PROBABLE CAUSE: "An inadvertent stall at a low altitude from which recovery was not effected."
Classification:
Loss of control
Sources:
» CAB File No. 1-0089Photos
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Boeing 377
- 56 built
- The first loss
- The first fatal accident
- The worst accident (at the time)
- 6th worst accident (currently)