HISTORY OF FLIGHTOn June 15, 2014, about 0945 Pacific daylight time, a Grumman American AA-5B, N28718, impacted the Pacific Ocean about 3 miles northwest of Florence Municipal Airport (6S2), Florence, Oregon. The private pilot and one passenger were fatally injured, and the airplane was destroyed. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Marginal visual meteorological conditions prevailed for the flight, and no flight plan was filed. The flight originated from 6S2 at about 0845. Witnesses reported that they observed the pilot depart the airport in marginal visual meteorological conditions. About one hour later a witness heard an airplane engine noise approaching the airport but could not see the airplane due to low ceilings and visibility, the witness also noted that the weather conditions were quickly deteriorating. Another witness reported that, while he was walking along the beach, he heard an airplane engine noise in the low clouds estimated to be 100 ft. above ground level (AGL). The witness reported that a small airplane then emerged from the clouds above the river traveling westbound away from the airport. The pilot then "pushed the throttle up, pitched up, and reentered the cloud[s]." Shortly after, he observed the airplane exit the low overcast about 400 yards offshore in a near vertical attitude with the right wing low before it impacted the ocean. There was no radar data available of the accident airplane or the departure airport. PERSONNEL INFORMATIONThe pilot, age 69, held a private pilot certificate for airplane single-engine land issued December 19, 2008, and a third-class airman medical certificate issued July 29, 2013 with the limitation that he must wear corrective lenses. The pilot's logbook was not recovered for examination. On the application for his most recent medical certificate, he reported 660 total flight hours. The pilot was not instrument rated. AIRCRAFT INFORMATIONThe four-seat, low-wing, fixed-gear airplane, serial number AA5B-0772, was manufactured in 1978. It was powered by a Lycoming O-360-A4K 180-hp engine and equipped with a Sensenich model 76EM8S10-0-64 fixed-pitch propeller. Review of copies of maintenance logbook records revealed an annual inspection was completed on April 1, 2014, at a recorded tachometer reading of 1013.0 hours, airframe total time of 3062.4 hours, and 968.1 engine hours since major overhaul. The tachometer and the Hobbs hour-meter were not located at the accident site which precluded determining the current readings. METEOROLOGICAL INFORMATIONA review of recorded data from the 6S2 automated weather observation station 2 ½ miles southeast of the accident site revealed that, at 0955, conditions were wind from 270 degrees at 5 knots, visibility of 1 ¼ mile, temperature and dew point temperature 13 degrees Celsius, and overcast clouds at 300 feet above ground level (agl). The Geostationary Operational Environmental Satellite 15 (GOES-15) infrared image at 0945 PDT (1645Z) depicted a band of low stratiform type clouds over the Oregon coast and the accident site with cloud tops near 13,500 feet. AIRPORT INFORMATIONThe four-seat, low-wing, fixed-gear airplane, serial number AA5B-0772, was manufactured in 1978. It was powered by a Lycoming O-360-A4K 180-hp engine and equipped with a Sensenich model 76EM8S10-0-64 fixed-pitch propeller. Review of copies of maintenance logbook records revealed an annual inspection was completed on April 1, 2014, at a recorded tachometer reading of 1013.0 hours, airframe total time of 3062.4 hours, and 968.1 engine hours since major overhaul. The tachometer and the Hobbs hour-meter were not located at the accident site which precluded determining the current readings. WRECKAGE AND IMPACT INFORMATIONThe airplane was believed to have impacted the Pacific Ocean about ¼ mile from the shoreline. The main wreckage was not located; however, various components that washed up on shore were recovered. Some of the items recovered were the airplanes right wing flap, rudder, elevators, right landing gear wheel, pieces of airplane sheet metal, and various parts of the airplane's interior. The remainder of the airplane was not located. Due to the limited number of recovered airplane components, a postaccident airframe and engine examination was not completed. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy was performed on the pilot on June 20, 2014 by the Oregon State Police Medical Examiner. The cause of death was reported as blunt force trauma. The pilot had reported no chronic medical conditions and no chronic medication use to the Federal Aviation Administration (FAA) or his personal physician. The autopsy identified moderate single vessel coronary artery disease without evidence of a pervious scar or muscle injury. Postaccident toxicology conducted by the FAA Civil Aerospace Medical Institute identified 6-ß-natrexol, the primarily metabolite of naltrexone, in the pilot's blood and liver. Naltrexone has only one use and it is an aid for people with alcohol or opioid abuse to maintain sobriety. Naltrexone alone is not known to be generally impairing, but early in treatment its use can precipitate symptoms of withdrawal. Despite multiple attempts, the reason for the pilot's use of this drug was unable to be determined.