On September 5, 1997, at 1445 hours mountain standard time, a Mooney M20E, N9217V, collided with the ocean following an engine failure in international waters in the Gulf of California, about 30 miles northeast of Loreto, Mexico. The aircraft sank in 900 feet of water. The private pilot and his three passengers were not injured. The aircraft was being operated as a personal flight under 14 CFR Part 91 when the accident occurred. The flight originated in Mesa, Arizona, at 0500. Instrument meteorological conditions prevailed at the accident site and a VFR flight plan was filed. The airplane made a stop en route to Loreto at Ryan Field, Tucson, Arizona, where the pilot refueled the airplane. The airplane had 4 hours of fuel onboard. The airplane took off from Ryan Field at 1200. The pilot told the Federal Aviation Administration Flight Standards District Office that he had been in the air approximately 2 hours 30 minutes when the engine quit. He stated that he had received an updated weather briefing from Hermosillo, which did not report any convective activity or PIREPS. The pilot said he saw clouds in front of the airplane when he was talking to Loreto tower. He descended to 3,000 feet and found that the clouds were "all the way to the water." After the engine quit, he declared a "Mayday" and gave his position. He estimated that his ground speed was about 30 mph when he hit the water, with a 50-mph headwind. All four occupants were able to exit the aircraft wearing lifejackets as the airplane sank. One passenger swam 10 miles to shore and alerted authorities. The remaining three occupants of the airplane spent approximately 20 hours in the water before the Mexican Authorities rescued them. The operator of the aircraft told the insurance company representative that the pilot was a regular customer of the facility and had approximately 240 hours total flight time, 106 hours in high performance aircraft, and 15 hours in make and model. The operator of the aircraft had checked the pilot of the accident aircraft out in the Mooney M20E on February 15, 1997. The aircraft was not recovered.