Accident description
Last updated: 27 November 2014
Status:
Date:Tuesday 16 October 1956
Time:06:15
Type:Boeing 377 Stratocruiser 10-29
Operator:Pan American World Airways (Pan Am)
Registration: N90943
C/n / msn: 15959
First flight: 1949
Engines: 4 Pratt & Whitney R-4360-B6
Crew:Fatalities: 0 / Occupants: 7
Passengers:Fatalities: 0 / Occupants: 24
Total:Fatalities: 0 / Occupants: 31
Airplane damage: Damaged beyond repair
Location:1800 km (1125 mls) SW off San Francisco, CA, USA (   Pacific Ocean) show on map
Phase: En route (ENR)
Nature:Domestic Scheduled Passenger
Departure airport:Honolulu International Airport, HI (HNL/PHNL), United States of America
Destination airport:San Francisco International Airport, CA (SFO/KSFO), United States of America
Flightnumber: 6
Narrative:
PanAm Stratocruiser N90943 was on a round-the-world flight from Philadelphia to San Francisco with stops in Europe, Asia and the Pacific. The aircraft took off from Honolulu at 20:26 HST for the last leg of the flight to San Francisco. The flight was cleared via Green Airway 9, track to 30deg N, 140deg W at FL130 and then at FL210 to San Francisco. About half way, at 01:02 the crew requested a VFR climb to FL210, which was approved. Immediately after reaching this altitude (at 01:19) the no. 1 engine oversped. Reduction of airspeed didn't help and the prop could not be feathered, so the engine was cut. As the aircraft was losing altitude a ditching seemed imminent. US Coast Guard weather station 'November' was contacted at 01:22 about the possible ditching. Climb power was then applied to the remaining engines. The no. 4 engine however, was only developing partial power at full throttle. Despite these problems the crew managed to maintain altitude at 5000 feet at an airspeed of 135 knots. Remaining fuel was insufficient however to reach San Francisco or fly back to Honolulu. The crew decided to orbit the cutter 'November' and wait for daylight to carry out the ditching. Meanwhile electric water lights were laid by the cutter to illuminate a track for the aircraft. At 02:45 the no. 4 engine backfired and failed. The prop was feathered. At 05:40 the captain contacted the cutter again about the intended ditching time and descended to 900 feet. The ditching was carried out at 06:15 with full flaps, gear up and at a speed of 90 knots. The fuselage broke off aft of the main cabin door. The tail section swung to the left, trapping the liferaft launched from the main cabin door. Some 3 minutes after all occupants had been rescued, at 06:32 the aircraft sank at position 30deg01.5'N, 140deg09'W.

PROBABLE CAUSE: "An initial mechanical failure which precluded feathering the no. 1 propeller and a subsequent mechanical failure which resulted in a complete loss of power from the no. 4 engine, the effects of which necessitated a ditching."

Classification:
Ditching

Sources:
» ICAO Accident Digest No.8, Circular 54-AN/49 (133-137)


Photos

photo of Boeing 377 Stratocruiser 10-29 N90943
photo of Boeing 377 Stratocruiser 10-29 N90943
photo of Boeing 377 Stratocruiser 10-29 N90943
photo of Boeing 377 Stratocruiser 10-29 N90943
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Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Honolulu International Airport, HI to San Francisco International Airport, CA as the crow flies is 3835 km (2397 miles).

This information is not presented as the Flight Safety Foundation or the Aviation Safety Networkĺs opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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Boeing 377

  • 6th loss
  • 56 built
  • 6th worst accident (at the time)
  • 8th worst accident (currently)
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 Pacific Ocean
  • 45th worst accident (at the time)
  • 88th worst accident (currently)
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