LAX08LA253

The pilot's failure to maintain aircraft control while in cruise flight due to spatial disorientation. Contributing to the accident was turbulence and clouds.

During the instrument-flight-rules flight at 11,000 feet mean sea level, the pilot's last transmission to air traffic control confirmed his altimeter setting. Shortly thereafter, radar data indicated that the airplane started a descending right-hand turn. The final radar return was at 9,700 feet msl. The airplane wreckage was located about 1 mile west of the final radar return, at a terrain elevation of 3,830 feet. The debris field was consistent with an in-flight breakup, with airplane wreckage distributed over a distance of 0.5 miles. A study of the meteorology in the vicinity at the time of the accident indicated that a broken to overcast ceiling existed between 5,000 to 6,000 feet msl and extended up to 14,000 feet msl. Satellite imagery depicted cloud top temperatures of -1 to -3 degrees C between 11,000 and 12,000 feet msl. The location of the last radar return was immediately downwind of Mt. Rainier and the sounding wind profile indicated favorable conditions for mountain wave formation. Digital photos of Mt. Rainier taken a few minutes before the accident were recovered from a camera onboard the airplane. The images depict a clear view of clouds surrounding Mt. Rainier and that the airplane was operating immediately above a broken-to-overcast cloud layer, in visual meteorological conditions. The radar track combined with weather radar imagery and satellite imagery indicated that the airplane was in instrument meteorological conditions (IMC) at the time it entered the descending right turn and dropped below the radar floor. Flight performance data recovered from cockpit instrumentation indicate that 5 minutes prior to the accident the airplane experienced continuous turbulence ranging from 0.77 to 1.5 vertical g's, consistent with a mountain wave encounter. Upon entering IMC conditions, the airplane began a right turn that developed into a spiral descent. During the last few seconds of flight the airplane was oriented 88.6 degrees nose down, 113 degrees angle of bank, and 290 knots. Upon exiting the bottom of the cloud layer, at 6,135 msl, the airplane experienced a rapid onset of g's that exceeded the strength of the airplane. The sudden onset of g-load is constant with the pilot's attempt to recover from the rapid descent and unusual attitude.

HISTORY OF FLIGHT On August 1, 2008, about 1433 Pacific daylight time (PDT), an amateur built experimental category, Long Lancair ES, N45EL, disappeared from radar and radio contact was lost 40 miles northwest of Yakima, Washington. The airplane wreckage was located 9 miles northwest of Cliffdell, Washington. The private pilot operated the airplane under the provisions of Title 14 Code of Federal Regulations, Part 91. The pilot and single passenger were killed, and the airplane was destroyed. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed. The flight originated at Ketchikan, Alaska, about 0957 Alaska daylight time (ADT). The pilot and his passenger were traveling from Ketchikan to Mountain Home, Idaho. A review of the Federal Aviation Administration (FAA) air traffic control documents revealed that the pilot received a standard weather brief from the Juneau Automated Flight Service Station at 0608 ADT, and filed an IFR flight plan. At 0954 ADT, N45EL was released for departure. While en route the pilot received normal services from Anchorage Air Route Traffic Control Center (ARTCC) and Seattle Terminal Radar Approach Control Facility (TRACON). At 1422 PDT, the pilot checked in with Seattle ARTCC at 11,000 feet mean sea level (msl) with a clearance to proceed direct to Yakima. At 1432 PDT, the pilot confirmed his altimeter setting, 29.87, which was the pilot's last transmission. At 1433 PDT, an altitude deviation to 9,700 feet was noted by the controller and then radar and radio contact were lost. Repeated attempts to contact N45EL were unsuccessful. Examination of the radar file depicted the airplane on a steady southeast course at 11,000 feet msl. At 1431:30, the track started a descending right-hand turn. The final radar return was at 1432:06, at 9,700 feet msl. The airplane wreckage was located about 1 mile west of the final radar return, at a terrain elevation of 3,830 feet. The debris field consisted of individual airplane parts, left wing, right wing, horizontal stabilizer, fuselage, and engine, distributed over a distance of 0.5 miles, in a densely wooded mountain slope. No initial point of impact was identified. PERSONNEL INFORMATION The pilot, age 68, held a private pilot certificate for airplane single-engine land with an instrument airplane rating, issued on December 9, 2001. He held a third-class medical certificate, issued in May 2008, with the limitation that he wear lenses for distant vision, and possess glasses for near vision. The pilot's logbook was examined. The most recent entry was dated July 16, 2008, with a recorded 592.7 hours total time, 176 hours simulated instrument time, and 4 hours of actual instrument time. In the last 30 days he had logged 10.8 hours, all in the accident airplane. He had logged a total of 266.2 hours in the accident airplane. The pilot's most recent flight review was on May 14, 2008, and his instrument proficiency check was dated July 9, 2008. AIRCRAFT INFORMATION The four seat, single engine, low wing, fixed gear, experimental category airplane was constructed by the pilot, and was issued an airworthiness certificate on September 12, 2004. The airplane was powered by a Teledyne Continental IO-550 motor. The propeller was an Aero Composites three bladed propeller. The maintenance logbook recorded the most recent annual inspection was completed on April 5, 2008. The most recent oil change was on July 14, 2008, at a total time of 267.2 hours. METEROLOGICAL INFORMATION The northwest portion of the National Weather Service (NWS) Surface Analysis Chart for 1400 PDT (2100Z) depicted a low pressure system with a central pressure of 1007 hectopascals (hPa) over southeastern British Columbia north of the Washington and Idaho boarders, and a high pressure system located off the Pacific northwest coast. A cold front extended from the low southwestward through Washington, Oregon, and into the Pacific Ocean. The accident site was located behind the cold front. Several station models over western Washington and Oregon, to the west and southwest of the accident site, indicated light to heavy rain showers, with overcast skies. The closest station model depicted was from Yakima (KYKM) located southeast of the accident site, which depicted winds from the west-southwest at approximately 10 knots, scattered clouds, temperature of 78 degrees Fahrenheit (F) and a dew point of 48 degrees F, with a sea level pressure of 1010.8 hPa. The station model northwest of the accident site from Stampede Pass (KSMP) indicated calm winds, overcast skies, temperature of 52 degrees F, dew point of 48 degrees F, and sea level pressure of 1015.4-hPa. The northwest portion of the NWS Weather Depiction Charts for 1500 PDT (2200Z) depicts the coastal section of Washington near the Seattle area indicated IFR conditions due to low overcast ceilings near 600 feet above ground level (agl). Surrounding that area was an area of marginal visual flight rules (MVFR) conditions that extended over western Washington and a second area over Oregon and northern California. Visual flight rule (VFR) conditions were depicted over the accident site and all of central and eastern Washington and Oregon. The Yakima station mode indicated ceilings broken at 9,000 feet agl in the immediate vicinity of the accident site. The NWS Radar Summary Chart for 1421 PDT (2121Z) depicted several areas of light to strong intensity echoes over central Washington associated with rain showers with tops to 29,000 feet. The regional radar mosaic chart from the National Center for Atmospheric Research (NCAR) for 1502 PDT indicated a band of echoes along the Cascade Mountain Range to the west of the accident site, with several areas of scattered echoes over central Washington and northern Oregon to the southwest of the accident site. A small area of echoes was identified in the immediate vicinity of the accident site. The closest weather reporting facility was from the NWS remote automated surface observation system (ASOS) located at Stampede Pass, in Kittitas County, Washington, 13 miles northwest of the accident site at an elevation of 3,967 feet msl. The following conditions were reported surrounding the time of the accident; Stampede Pass weather at 1423 PDT (2123Z), automated, wind from 290 degrees at 9 knots; visibility 10 miles; scattered clouds at 800 feet, ceiling overcast at 1,500 feet; temperature 11 degrees C; dew point 8 degrees C; altimeter 30.01 inHg. The next closest weather reporting facility was from Bowers Field (KELN), Ellensburg, located approximately 28 miles east of the accident at an elevation of 1,764 feet. The airport had an automated weather observation; Bowers Field weather observation at 1453 PDT (2153Z), automated, winds from 310 degrees at 9 knots; visibility 10 miles; few clouds at 7,500 feet, scattered at 9,000 feet; temperature 25 degrees C; dew point temperature 9 degrees C; altimeter setting 29.89 inHg. Remarks: automated observation system, rain began at 1432, ended at 1442 PDT; sea level pressure 1010.9 hPa; hourly precipitation total trace or less than 0.01 inches; temperature 25.0 degrees C; dew point 9.4 degrees C. Upper wind data documented the wind profile over the region. The profile indicated surface winds from the southwest at 13 knots, with little directional variation with height and wind speeds increasing to 25 knots at 4,800 feet, then decreased and increased again, with wind speeds in excess of 50 knots above 18,000 feet. The mean 0-6 kilometer (18,000 feet) wind was from 236 degrees at 38 knots, with the maximum wind from 230 degrees at 98 knots identified at 41,000 feet. At the accident airplane's cruising level of 11,000 feet, the wind was from 245 degrees at 27 knots with a temperature of -1 degree C. The sounding indicated a chance of light to moderate turbulence at that level. The sounding wi