HISTORY OF FLIGHT On December 10, 1996, about 0930 Pacific standard time, N4758R, a Bell 47G helicopter, operated by Wildhorse Helicopters, Inc. as a restricted category aircraft, impacted terrain and was destroyed while maneuvering north of Pendleton, Oregon. Both commercial pilots were fatally injured. Instrument meteorological conditions prevailed and no flight plan had been filed. The positioning flight was conducted under 14 CFR 91. According to the tower manager at the contract air traffic control tower at the Eastern Oregon Regional Airport, the accident pilot had radioed a request for a takeoff clearance from the airport about 7:30 a.m. on the morning of the accident. The tower manager provided the clearance. He remembered that the clearance was for a flight of two helicopters. He observed the two helicopters hover taxi to the south end of the taxiway, then take off in formation to the north. He stated that the weather conditions were "beautiful" at the time of the takeoff. According to local law enforcement personnel reports and their interview of an operator employee (attached), both helicopters flew to a ranch located north of Pendleton to conduct agricultural spraying operations on the morning of the accident. The weather conditions gradually worsened during the morning as fog began to roll in. Both pilots ceased their spraying and landed their helicopters at the ranch. An employee downloaded the spray chemicals out of the accident helicopter, and the pilot of the other helicopter and a dog boarded the accident helicopter with the intention of flying back to the Eastern Oregon Regional Airport in Pendleton before the fog thickened. The operator employee stated that the accident helicopter departed the ranch about 0900. He then departed the ranch by ground vehicle after he had downloaded the spray chemicals. He had driven past the accident site about the time of the accident, but he could not see more than 100 feet because of the fog. Later that morning, the Eastern Oregon Regional Airport tower manager observed a "fog bank" quickly "roll in" over the airport, and the fog was accompanied by winds out of the west of about 30 knots. He remembered that a Federal Express Cessna Caravan pilot had contacted him and attempted an approach into the airport. The Federal Express pilot could not make it in and announced that he was diverting to LaGrande, Oregon. Less than 5 minutes later, the accident pilot contacted the tower manager, stated that he was "15 miles out" from the airport, and requested "what's your weather." The tower manager remembered that he read the accident pilot the most recent weather observations, which included 1/8-mile visibility at the airport. The tower manager also remembered telling the pilot that he could see the weather was clearing near "Writhe Ridge," located about two miles south southwest of the airport. The tower manager remembered that the pilot responded with "roger" and made no comments about Writhe Ridge, the visibility at the airport, or any distress calls. About one minute later, the accident pilot reported that he was "about 15 miles out" from the airport, and he was "on top...looking for a hole." The tower manager acknowledged the transmission and asked the pilot to "give me a call when you get closer," so that a landing clearance could be issued, if possible. This was the last communication with the pilot that the tower manager remembered. He stated that no distress calls were ever made by the accident pilot. The tower manager remembered that about 45 minutes had passed after the accident pilot's last transmission to the time he heard a transmission from the local fire department that a fire truck was being dispatched to an aircraft accident. Witnesses in the area reported "heavy fog" at the time of the accident. No distress calls were reported. An examination of the accident site revealed that the aircraft impacted near the top of a hill. No evidence of preimpact mechanical malfunction was found. The airplane wreckage was located along featureless, rolling hills about 7 nautical miles north of the Eastern Oregon Airport at an elevation of about 1,900 feet above mean sea level (msl). The accident occurred during the hours of daylight. PERSONNEL INFORMATION The first pilot, a 51-year-old business man owned the helicopter and the operation. He was a certificated commercial pilot with ratings in airplane single-engine land, airplane multiengine land, and rotorcraft-helicopter. He was also instrument rated and held an FAA airframe and powerplant mechanic certificate. According to FAA records, the first pilot was issued a Second Class Medical Certificate on September 11, 1996, with the limitation that he "must wear corrective lenses." He reported that he had logged 10,000 hours of total flight time at the time of his most recent FAA medical examination. The Safety Board was unable to recover the first pilot's personal flight log books. The second pilot, a 52-year-old male, was a certificated commercial pilot with ratings in airplane single-engine land, airplane multiengine land, and rotorcraft-helicopter. He was not instrument rated. According to FAA records, the second pilot was issued a Second Class Medical Certificate on April 1, 1996, with no limitations. He reported that he had logged 10,000 hours of total flight time at the time of his most recent FAA medical examination. The Safety Board was unable to recover the second pilot's personal flight log books. AIRCRAFT INFORMATION The aircraft, a 1972 Bell model 47G3-B2A helicopter, was owned, operated and maintained by the first pilot. The helicopter was not equipped for instrument flight. The aircraft's most recent engine and airframe logbooks were not found by investigators. According to the most recent FAA Form 3112, Inspection and Surveillance Record (attached), dated March 26, 1996, the aircraft had logged a total time of 5,078 hours and had received an annual inspection on November 3, 1995. METEOROLOGICAL INFORMATION The following meteorological conditions were recorded (copies of records attached) by the Automated Surface Observation Station at Eastern Oregon Regional Airport in Pendleton about the time of the accident: measured visibility 1/4 -mile in fog; vertical visibility 100 feet; wind 290 degrees magnetic at 7 knots; temperature 37 degrees F; dew point 37 degrees F; altimeter setting 29.28 inches. The airport is located about 7 nautical miles south of the accident site at a ground elevation of 1,493 feet msl. WRECKAGE AND IMPACT INFORMATION The airplane wreckage was examined at the accident site one day after the accident by Federal Aviation Administration (FAA) aviation safety inspectors from Portland, Oregon (FAA Inspectors' reports attached). The wreckage scatter path was oriented along a magnetic bearing of south-southwest. The main wreckage was contained in one local area; no evidence of an in-flight structural failure, in-flight fire, or explosion was found. Verification of flight control continuity was impossible due to the disintegration of the aircraft from impact forces. No evidence of a flight control malfunction was found. The main rotor blades and tail rotor blades had separated from their hub and were found near the main wreckage area. According to the FAA inspectors, ground impact scars and rotor blade damage indicated that the helicopter impacted terrain in a nose-low, right bank attitude. The engine underwent an external examination, partial disassembly, and detailed inspection at the accident site; no evidence of any preimpact mechanical malfunctions was found. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the first pilot by Dr. James B. Sawyer, M.D., at Blue Mountain Pathology, Inc., in Pendleton, Oregon, for the State of Oregon Medical Examiner Division, on December 11, 1996. The cause of death was listed as "Multiple traumatic injuries." No evidence of pilot impairment was found. A toxicological analysis was ordered and performed on specimens taken from the pilot by the FAA Civil Aeromedical Institute in Oklahoma City, Oklahoma. According to their report (attached), results were negative for carbon monoxide, cyanide, alcohol, and all screened drugs.