HISTORY OF FLIGHT On March 6, 2009, about 1353 Pacific standard time, a Cessna 172N, N726RJ, collided with the ocean about 40 nautical miles (nm) west of Oceanside, California. Golden Wings Flying Club was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The certificated private pilot is presumed to have sustained fatal injuries; the airplane was destroyed by impact forces. The local personal flight departed Montgomery Field, San Diego, California, about 1148. Visual meteorological conditions prevailed, and no flight plan had been filed. The Federal Aviation Administration (FAA) reported that witnesses observed an airplane entering the ocean in a nose-low attitude. The witnesses maneuvered their boats to the site, and observed debris and an oil slick. The Coast Guard recovered several pieces of debris including a seat. Golden Wings reported that a pilot rented one of their Cessna 172 airplanes, N726RJ. The renter had the airplane scheduled between 1100 and 1700. The airplane and pilot did not return from the scheduled flight, and they were not located at neighboring airports. Recorded radar data depicted a target at a mode C altitude of 700 feet that was ascending from Montgomery Field at 1148. It climbed along the coastline on a northwesterly heading. It was climbing through 11,500 feet when it made a left turn to a westerly heading near Newport Beach, California. The target ascended through 12,500 feet at 1255:35, and through 14,000 feet at 1310:10. It then turned left to the south about 1323. It tracked around Catalina Island, and turned to a southeasterly heading toward San Diego. The target remained above 14,000 feet until 1352:25. At this point, the target was descending, and began turning to the right (west). It lost 13,000 feet in the last minute, and the last target was in the immediate vicinity of the reported accident site. PERSONNEL INFORMATION A review of FAA airman records revealed that the 75-year-old pilot had a private pilot certificate with a rating for airplane single-engine land. It was issued on September 26, 2007. He held a third-class medical certificate issued on March 5, 2008. It had the limitations that the pilot must wear corrective lenses for near and distant vision. A review of the pilot’s logbooks indicated a total time of 252 hours; all were in single-engine airplanes. Approximately 207 hours had been accumulated in the make and model airplane involved in the accident, with 113 hours as pilot-in-command. The pilot had flown 16 hours in the previous 90 days, and 2 hours in the previous 30 days. AIRCRAFT INFORMATION The airplane was a Cessna 172N, serial number 17272431. A review of the airplane’s logbooks revealed that the airplane had a total airframe time of 5,389 hours at the last 100-hour inspection on November 3, 2008. The logbooks contained an entry for an annual inspection dated April 15, 2008. The logbooks indicated that the engine was a Textron Lycoming O-320-H2AD, serial number L-6966-76T. Total time in service recorded on the engine at the last 100-hour inspection was 1,276 hours. METEOROLOGICAL INFORMATION The closest official weather observation station was Oceanside(KOKB), which was 40 nautical miles (nm) and 050 degrees from the accident site. The elevation of the weather observation station was 28 feet mean sea level (msl). An aviation routine weather report was issued at 1352 PST. It stated: winds from 220 degrees at 10 gusting to 17 knots; visibility 10 miles; skies clear; temperature 15/59 degrees Celsius/Fahrenheit; dew point 7/45 degrees Celsius/Fahrenheit; altimeter 30.05 inches of mercury. MEDICAL AND PATHOLOGICAL INFORMATION The pilot was not recovered, and no autopsy or toxicology testing could be performed. The airplane was not equipped with an oxygen system. According to an aviation medicine textbook (Gradwell, D.P. 2006. Hypoxia and Hyperventilation. In: Ernsting's Aviation Medicine, Fourth Edition, Eds. D.J. Rainford and D.P. Gradwell. Hodder Arnold, London, U.K. p. 53), from 10,000 to 15,000 feet, an individual without supplemental oxygen "exhibits no or few signs and has virtually no symptoms [of hypoxia]. The ability to perform skilled tasks is impaired, however, an effect of which the subject is frequently unaware.” The FAA Aeronautical Information Manual, paragraph 8-1-2, "Effects of Altitude," describes hypoxia as "a state of oxygen deficiency in the body sufficient to impair functions of the brain and other organs." The textbook also notes that "an individual breathing air at 8,000 feet may take significantly longer to achieve optimum performance at novel tasks than is the case at sea level. For example, this degree of hypoxia has been found to double the reaction times of initial responses to a complex choice-reaction task as compared with responses at sea level. The intensity of this effect increases with altitude and complexity of the task - markedly so above 12,000 feet." (Gradwell, 2006, p. 51). Studies also noted that research subjects exhibited mental performance impairment during task tests that were begun after only 5 minutes (Kelman, G.R.; Crow, T.J. 1969. Impairment of mental performance at a simulated altitude of 8,000 feet. In: Aerospace Medicine 40 (9). pp. 981-982) and 10 minutes (Denison, D.M.; Ledwith, F.; Poulton, E.C. 1966. Complex reaction times at simulated cabin altitudes of 5,000 feet and 8,000 feet. In: Aerospace Medicine. pp. 1010-1013. October 1966) of exposure to a simulated altitude of 8,000 feet. Federal Aviation Regulation (FAR) 91.211 governs the use of supplemental oxygen. It states that the required minimum flight crew must be provided and use supplemental oxygen for that part of the flight that is of more than 30 minutes duration at cabin pressure altitudes above 12,500 feet msl up to and including 14,000 feet msl. At cabin pressure altitudes above 14,000 feet msl, the required minimum flight crew must be provided with and use supplemental oxygen. ADDITIONAL INFORMATION The Coast Guard recovered several pieces of wreckage. One piece had a part number, which Cessna Aircraft Company identified as an upper left hand fairing from a Cessna 172. The accident airplane fell within the range of serial numbers of airplanes for which this part was applicable.