On December 22, 1996, at 1308 hours Pacific standard time, a homebuilt experimental Farhat RV6A, N961CP, collided with mountainous terrain near Julian, California, after encountering icing conditions, turbulence, and downdrafts. The aircraft was destroyed, and the pilot and his passenger sustained fatal injuries. The aircraft was operated by the pilot/owner when the accident occurred. The flight originated from Bullhead City, Arizona, at 1214 mountain standard time. Instrument meteorological conditions prevailed at the accident site and an instrument flight plan was filed. A review of Federal Aviation Administration (FAA) records disclosed that the pilot received a preflight weather briefing and an update briefing before departure from an air traffic control specialist (ATCS). He was advised of SIGMET PAPA 14 for moderate occasional severe turbulence below 16,000 feet msl. He was also advised of AIRMET ZULU for occasional moderate rime and mixed icing precipitation below 20,000 feet; AIRMET SIERRA for mountains occasionally obscured in clouds and precipitation; and AIRMET TANGO for turbulence and low level wind shear. The ATCS told the pilot that the freezing level was now 9,000 feet at his departure airport and was trending lower. He also told him that conditions were expected to improve overnight; however, the pilot decided to depart that day and filed an IFR flight plan with an altitude request for 10,000 feet. At 1255, the pilot reported to the controller at the San Diego east radar sector that he was experiencing icing conditions and needed a lower altitude. The pilot was warned about light to moderate turbulence that had been reported below his assigned altitude as well as severe up and down drafts in the vicinity of the Julian VORTAC. The controller advised the pilot that his request was approved. He was cleared down to the minimum vectoring altitude (MVA) of 8,000 feet and told that his position was now 7 miles east of Julian. The pilot replied that wanted to delay his descent until crossing Julian. The controller acknowledged his request and asked that he report upon starting the descent. As the aircraft crossed the Julian VORTAC the pilot reported that he was in the clear between layers at 9,500 feet, and that the air was smooth. The controller asked the pilot to depart Julian on a heading of 195 degrees. At 1303, the pilot reported that he was starting his descent to 8,000 feet. At 1305, the pilot was asked to start a right turn to a heading of 210 degrees. The pilot replied that he was unable to hold 8,000 feet. The controller asked the pilot to turn further right to a heading of 270 in order to stay within the lower MVA. The pilot was then advised that he was about to enter an area with a higher MVA and asked if he was able to maintain terrain obstruction clearance. The pilot replied that he was in the clouds. The pilot was then advised to turn further right to a heading of 290 degrees and to keep the turn as tight as possible in order to stay in the lower MVA. He was also asked to try to maintain at least 7,000 feet. The pilot replied that he thought he could. At 1307, the controller requested that the pilot fly a heading of 220 degrees. The pilot's response was unintelligible. A few seconds later he was told to try to maintain 7,000 feet and to turn left to a heading of 190 degrees. Again, the pilot's response was unintelligible. The controller continued to try to contact the pilot and asked him to squawk ident, but the pilot did not respond. An FAA inspector reported that the aircraft was found at 33 degrees 6.23 minutes north latitude and 116 degrees 34.06 minutes west longitude, at a terrain level of about 4,600 feet msl. The debris and ground scars covered a distance of about 150 feet with the aircraft coming to rest on a heading of 080 degrees. The terrain at the accident site sloped lower along a 30-degree incline toward the east. A representative of the engine manufacturer examined the powerplant under the supervision of an FAA inspector. No preimpact mechanical malfunctions or abnormal conditions were observed during the examination. The aircraft was not equipped with anti-icing or deicing equipment. A Safety Board weather specialist prepared a meteorological report which is appended to this report. The report identified conditions existing at the time of the accident that were conducive for clouds, turbulence, windshear, and icing at the pilot's assigned altitude, in the vicinity of the accident site. An autopsy was conducted by the San Diego County Coroner's Office, with specimens retained for toxicological examination. The toxicological test results were negative for alcohol and all screened drug substances. The ELT did not activate on impact. A visual inspection revealed that the coaxial cable to the external antenna had separated. The BNC male connector that was used in the installation was not part of the model AK-450, which was certified under FAA TSO C-91a. The unit showed no external damage and passed a functional bench test administered by the ELT manufacturer.