HISTORY OF FLIGHTOn July 4, 2016, about 2300 Pacific daylight time, a Cessna 172F, N7870U, impacted the Pacific Ocean shortly after takeoff from Brookings Airport (BOK), Brookings, Oregon. The private pilot and two passengers were fatally injured, and the airplane was destroyed. The airplane was registered to Cessna 7870U, LLC, and was operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Night visual meteorological conditions prevailed for the third leg of the cross-country flight, and no flight plan was filed. The destination was Grants Pass Airport, Grants Pass, Oregon. According to the co-owner of the airplane, on the morning of the accident, the pilot departed from Hollister Municipal Airport (CVH), Hollister, California. According to airport documentation and a fuel receipt, he refueled at Rohnerville Airport (FOT), Fortuna, California, that afternoon before continuing to BOK, where he landed about 1430. The pilot did not report to the co-owner any problems with the airplane during that flight. A witness located about 1.5 miles west of BOK and near the ocean shoreline, reported that around the time of the accident, he heard an airplane flying nearby and assumed that it was taking off from BOK. As the airplane continued, he heard a reduction in engine power, like a pilot throttling back while landing, but he could not remember whether it stopped before it went out of hearing range. He further stated that the engine did not sputter. Review of the recorded radar data depicted that the airplane turned left to a west heading shortly after takeoff and then climbed to about 700 ft above the ground as it neared the ocean shoreline. The area was sparsely populated. The last recorded radar target was near the witness's location, west of BOK, and about 1.5 miles southeast of where personal effects from the occupants of the airplane were found washed ashore. Information provided by the Federal Aviation Administration (FAA) revealed that the pilot's family contacted local authorities after they became concerned when the pilot did not arrive at his intended destination. The FAA subsequently issued an alert notification that was then cancelled on July 7 after personal effects from the occupants of the airplane were found washed ashore on the beach about 3 miles northwest of BOK. PERSONNEL INFORMATIONThe pilot held a private pilot certificate with an airplane single-engine land rating. He did not hold an instrument rating. He was issued an FAA third-class airman medical certificate on January 13, 2014, with the limitation that he must wear corrective lenses. According to the pilot's logbook, he had accumulated 207 total flight hours, all of which were in the accident airplane. The last entry recorded in the pilot's logbook was dated March 7, 2016, and was for a cross-country trip with a total duration of 13.87 flight hours of which 3 hours were at night. No other night flight time was recorded in the 6 months before the accident. AIRCRAFT INFORMATIONThe four-seat, high-wing airplane, serial number (S/N) 17251870, was manufactured in France in 1964 as a flight training airplane for the United States Air Force. It was powered by a Continental Motors O-300 engine. Review of the maintenance records showed that the engine was overhauled on November 15, 2013, at a total operating time of 4,372 hours. The last annual inspection was completed on November 11, 2015, at which time the engine had accumulated a total of 279 hours since the overhaul. METEOROLOGICAL INFORMATIONThe nearest weather reporting station was BOK. According to recorded information, at 2256, the weather conditions were winds calm, visibility 10 statute miles or greater, sky clear, temperature 13°C, dew point 09°C, and an altimeter setting of 30.06 inches of mercury. According to the Astronomical Applications Department of the United States Naval Observatory, the official sunset was at 2056; the official end of civil twilight was at 2130; and the official moonset was 2104. AIRPORT INFORMATIONThe four-seat, high-wing airplane, serial number (S/N) 17251870, was manufactured in France in 1964 as a flight training airplane for the United States Air Force. It was powered by a Continental Motors O-300 engine. Review of the maintenance records showed that the engine was overhauled on November 15, 2013, at a total operating time of 4,372 hours. The last annual inspection was completed on November 11, 2015, at which time the engine had accumulated a total of 279 hours since the overhaul. WRECKAGE AND IMPACT INFORMATIONThe main wreckage was identified in high current waters about 2 miles west of BOK and was not recovered. The search and rescue efforts continued for over 30 days until the occupants were recovered. The nose landing gear assembly and seat foam were the only airplane parts recovered. ADDITIONAL INFORMATIONSpatial Disorientation According to the FAA Airplane Flying Handbook (FAA-H-8083-3), "night flying is very different from day flying and demands more attention of the pilot. The most noticeable difference is the limited availability of outside visual references. Therefore, flight instruments should be used to a greater degree.… Generally, at night it is difficult to see clouds and restrictions to visibility, particularly on dark nights or under overcast. The pilot flying under [visual flight rules] VFR must exercise caution to avoid flying into clouds or a layer of fog." The handbook described some hazards associated with flying in airplanes under VFR when visual references, such as the ground or horizon, are obscured. The handbook states that, "the vestibular sense (motion sensing by the inner ear) in particular tends to confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in the attitude of the airplane, nor can they accurately sense attitude changes that occur at a uniform rate over a period of time. On the other hand, false sensations are often generated; leading the pilot to believe the attitude of the airplane has changed when in fact, it has not. These false sensations result in the pilot experiencing spatial disorientation." MEDICAL AND PATHOLOGICAL INFORMATIONThe Oregon State Police Morgue, Oregon State Police Headquarters, Central Point, Oregon, performed an autopsy of the pilot. The cause of death was reported as severe blunt trauma. The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing that identified ethanol at 0.041 gm/dl in cavity blood and 0.017 gm/dl in urine. In addition, N-propanol was identified in cavity blood and urine. Ethanol is the intoxicant found in beer, wine, and liquor. Ethanol may also be produced in postmortem tissues by microbial action; when this occurs other alcohols such as N-propanol may also be formed.