On October 16, 1956, Pan Am Flight 6, an around-the-world commercial passenger flight (N90943) took off from Honolulu, Territory of Hawaii, at 8:26pm HST on the flight's concluding leg to San Francisco. After passing the point of no return, the number one engine entered an overspeeding regime. The First Officer, who was flying the plane, immediately slowed the plane by further reducing power and by extending the flaps, and then an attempt was made to feather the number one propeller.
The propeller would not feather and the engine continued to turn at excessive RPM. The captain then decided to cut off the oil supply to the engine. Eventually, the RPM declined and the engine seized. The propeller continued to windmill in the air stream, causing excessive parasitic drag, which significantly increased the fuel consumption. Climb power was then added to the remaining three engines, in an attempt to slow the rate of descent. The number four engine then began to fail, and soon was able to produce only partial power at full throttle. At 0245 the number four engine began to backfire, forcing the crew to shut it down and feather the propeller.
The crew calculated the additional aerodynamic drag left them with insufficient fuel remaining to reach San Francisco, or to return to Honolulu. At that time the United States Coast Guard maintained a ship known as Ocean Station November between Hawaii and the California coast. The plane was flown to the USCGC Pontchartrain's location and circled the station until daylight. They finally were able to level off at 2,000 feet, with just the power of the two remaining engines.
The captain decided to wait for daylight, since it was important to keep the wings level with the ocean swells, at the initial ditching impact. As the fuel was burned off while the plane circled the Coast Guard cutter, the plane was able to climb from 2,000 feet to 5,000 feet. At that altitude, several practice approaches were made, to ensure that the plane would be controllable at low aircraft speeds.
Aware of the Pan Am Flight 845/26 accident the year before, in which a Boeing 377's tail section had broken off during a water landing, the captain instructed the flight's purser to clear passengers from the back of the plane.
At 0540, Captain Ogg notified Pontchartrain that he was preparing to ditch. The cutter laid out a foam path for a best ditch heading of 315 degrees, to aid the captain's vision of his actual height above the water. After a dry run, the plane touched down at 0615, at 90 knots with full flaps and landing gear retracted, in sight of the Pontchartrain, at 30°01.5'N. 140°09'W.
One wing impacted a swell, causing the plane to rotate, inflicting damage to the nose section and breaking off the tail. Nevertheless, all 31 pax were rescued by the Coast Guard before the last pieces of wreckage sank, at 0635.