Tranquility, CA, USA
N8126L
Cessna T210L
About 1 hour into the flight the airplane entered an uncontrolled descent and broke up in flight. The pilot, who did not possess an instrument flight rating, had received a standard weather briefing from a flight service station prior to departure. The briefer advised the pilot that a cold front existed perpendicular to the airplane's route of flight that produced multiple cloud layers to 30,000 feet, overcast conditions, rain, nimbostratus clouds, moderate turbulence, and moderate icing conditions along the frontal boundary. The airplane's radar track depicted the airplane cruising at 13,400 feet mean sea level (msl) on a steady southeasterly course. Analysis of the weather conditions showed that the flight encountered instrument meteorological conditions and ice as it approached the frontal boundary. Weather radar imagery depicted an encounter with the western edge of two bands of radar echoes, which could be associated with strong up- or downdrafts that could result in an upset to the airplane. If the autopilot system were engaged it would have masked the trim and heading changes that usually accompanies ice accumulation, and upon disengagement of the autopilot system, the airplane would be in an unbalanced flight condition. Recorded radar data showed that the last radar return in line with the southeasterly course occurred at 0901:54, with a mode C reported altitude of 13,400 feet msl. The next three radar returns occurred between 0901:59 and 0902:14, and depicted the track in a right-hand turn and a descent to 12,400 feet msl, which was the last identified altitude. This change in altitude corresponded to a 3,000- to 4,000-feet-per-minute rate of descent. Numerous primary targets in patterns indicative of an in-flight breakup were identified in the same vicinity from 0902:14 to 0903:08. Examination of the wreckage revealed permanent set deformation of the structural elements of the wings and horizontal stabilizers that was indicative of positive aerodynamic loading beyond the structures yield point. All fractures were overload in character. The wreckage was widely scattered over a distance in excess of 1,600 yards.
1.1 HISTORY OF FLIGHT On April 7, 2005, at 0903 Pacific daylight time, a Cessna T210L, N8126L, broke up in flight and impacted terrain near Tranquility, California. The airplane was operated by the private pilot under the provisions of 14 CFR Part 91. The pilot and two passengers were fatally injured; the airplane was destroyed. Instrument meteorological conditions prevailed, and a flight plan had not been filed. The flight originated at Healdsburg Municipal Airport, Healdsburg, California, about 0800, with an intended destination of Scottsdale, Arizona. The pilot and two passengers were traveling to Scottsdale, on a weekend golf trip, where they were to meet up with other members of their party. The pilot received a weather briefing from Oakland Automated Flight Service at 0554. The airplane departed Healdsburg sometime before 0800. The initial radar track was picked up over the San Pablo Bay in the San Francisco area at 0801:30, at 11,600 feet mean sea level (msl). The track continued on a southeasterly course until over Crows Landing, California, where it made a deviation to the south. After the track passed over the San Luis Reservoir it turned left to regain its original southeasterly course. The track ended at 0902:21 in the vicinity of Tranquility. Radar data revealed that the altitude encoding transponder (mode C) reported a change of altitude of 1,000 feet from 12,400 to 13,400 feet msl between the times of 0848 and 0853. The final track segment depicted the airplane level at 13,400 feet msl and traveling in a southeasterly direction when it turned abruptly to the right. The last radar return was recorded at 0902:14, at a position of 36 degrees 37.22 minutes north latitude by 120 degrees 24.12 minutes west longitude, at an altitude of 12,400 feet msl. No record of radio communication between the pilot and air traffic control (ATC) was located by the Federal Aviation Administration (FAA) for the time period surrounding the accident. 1.5 PERSONNEL INFORMATION A review of FAA airman records from Oklahoma City, Oklahoma, revealed that the pilot held a private pilot certificate with a single engine land rating that was issued on June 3, 1992. The pilot did not hold an instrument rating. The pilot held a third-class medical certificate that was issued on January 1, 2005. No restrictions or limitations were listed on the medical. The pilot's flight logbook was recovered from the airplane wreckage. Examination of the logbook revealed that the pilot had accumulated 576.2 hours of single engine flight time. His last recorded flight occurred on March 16, 2005, and consisted of an insurance check ride in a PA-32. The entry made prior to that was dated November 18, 2004, where the pilot recorded a 2.8-hour flight in the accident airplane. The endorsement page of the logbook contained one entry, a flight review signed by a certified flight instructor (CFI) on September 14, 2003. 1.6 AIRCRAFT INFORMATION The airplane was a Cessna T210L, serial number 21060613, single engine, high wing, 6-place airplane. A review of the airplane's logbooks revealed a total airframe time of 3,415.2 hours at the last inspection. An inspection in accordance with the scope and detail of Appendix D of 14 CFR Part 43 (annual/100-hour inspection) was completed on September 24, 2004. The airplane was powered by a Teledyne Continental TSIO-520-H4 factory remanufactured engine, serial number 217474-R. An examination of the engine logbook revealed that the engine had been installed into the airplane on August 8, 2003. The engine was inspected in accordance with an annual inspection on September 24, 2004, at a total time since maintenance overhaul (TSMO) of 33.6 hours. The airplane had a factory installed Nav-O-Matic 400A autopilot, which provides altitude hold, heading hold, and VOR tracking. There were no autopilot discrepancies noted in the maintenance records. The airframe and power plant (A&P) mechanic who performed the annual inspection stated that the airplane's crew oxygen system had not been inspected during the annual and was not in service. A fuel receipt with the pilot's name on it was obtained from Healdsburg Aviation, Inc. The date and time on the receipt was April 7, 2007, at 06:56:51. The receipt recorded the total amount of fuel purchased was 58.094 gallons. The airplane's pilot operating handbook states in the limitation section that flight into known icing conditions is prohibited. 1.7 METEOROLOGICAL INFORMATION 1.7.1 Surface Analysis Chart The southwest section of the National Weather Service (NWS) Surface Analysis Chart for 0800 depicted a high-pressure system with a central pressure of 1027-millibar (mb) over Colorado. To the north, a low-pressure system with a central pressure of 1001-millibars (mb) was located over the Oregon and Nevada border with a cold front extending from the low south to southwestward into Nevada, central and southern California, and into the Pacific Ocean. The accident site was located in the cold air mass behind the position of the surface cold front. The station models behind the cold front, over central and southern California, indicated broken to overcast sky conditions. 1.7.2 Surface Observations The area surrounding the accident site was documented utilizing official NWS meteorological aerodrome reports (METARs) and specials (SPECI). The reports are in standard format, provided in plain language. The variation for wind at Fresno is 15 degrees east, and cloud heights are reported above ground level (agl). Madera Municipal Airport (KMAE), Madera, California Madera weather observation at 0853, automated, wind from 300 degrees at 8 knots; visibility 10 miles in light rain; ceiling broken at 3,500 feet, broken at 4,100 feet, overcast at 9,500 feet; temperature 12 degrees Celsius (C); dew point 9 degrees C; altimeter 30.02 inHg. Remarks: automated observation system, rain began at 0849; sea level pressure 1016.3-mb; hourly precipitation less than 0.01-inch (trace); temperature 11.7 degrees C; dew point 8.9 degrees C; thunderstorm sensor not operating. Lemoore Naval Air Station/Reeves Field (KNLC), Lemoore, California Lemoore Naval Air Station (KNLC) special weather observation at 0845, wind from 330 degrees at 10 knots; visibility 7 miles in light rain; a few clouds at 6,000 feet; ceiling broken at 14,000 feet, overcast at 20,000 feet; temperature 13 degrees C; dew point 7 degrees C; altimeter 30.00 inHg. Remarks: sea level pressure 1016.0-mb. Lemoore Naval Air Station (KNLC) weather observation at 0855, wind from 330 degrees at 13 knots; visibility 7 miles in light rain; ceiling broken at 5,000 feet, broken at 14,000 feet, overcast at 20,000 feet; temperature 12 degrees C; dew point 9 degrees C; altimeter 30.01 inHg. Remarks: sea level pressure 1016.2-mb; hourly precipitation less than 0.01-inch (trace); temperature 12.2 degrees C; dew point 8.9 degrees C. Fresno Yosemite International Airport (KFAT), Fresno, California Fresno weather observation at 0856, wind from 300 degrees true at 10 knots; wind 280 variable 350 degrees; visibility unrestricted at 10 statute miles; scattered clouds at 8,000 feet; ceiling broken at 14,000 feet, overcast at 18,000 feet; temperature 13 degrees C; dew point temperature 7 degrees C; altimeter 30.01 inHg. Remarks: automated observation system, sea level pressure 1015.9-mb; temperature 13.3 degrees C; dew point 7.2 degrees C. Merced Municipal Airport/Macready Field (KMCE), Merced, California Merced Municipal Airport special weather observation at 0830, automated, wind from 330 degrees at 8 knots; visibility 3 miles in light rain and mist; a few clouds at 600 feet; ceiling broken at 2,200 feet, overcast at 3,400 feet; temperature 11 degrees C; dew point 9 degrees C; altimeter 30.02 inHg. Remarks: automated observation system, hourly precipitation 0.06-inch; thunderstorm sensor not operating. Merced Municipal Airport weather observation at 0853, automated, wind from 010 degrees at 6 knots; visibility 4 miles in light rain and mist; a few clouds at 2,400 feet; ceiling broken at 3,000 feet, overcast at 6,000 feet; temperature 11 degrees C; dew point 9 degrees C; altimeter 30.02 inHg. Remarks: automated observation system, sea level pressure 1016.4-mb; hourly precipitation 0.11 inches; temperature 10.6 degrees C; dew point 8.9 degrees C; thunderstorm sensor not operating. 1.7.3 Satellite Information The GOES-10 (Geostationary Operational Environmental Satellite) infrared image at 0900 (6X magnification), with a standard MB temperature enhancement curve applied to the image to highlight the higher and colder cloud tops associated with deep convection, depicted an area of enhanced cloud cover associated high and cold cloud tops over California (including the accident site). The radiative cloud top temperature over the upset location was determined to be 228.20 degrees Kelvin (K), or -44.95 degrees C, which corresponded to cloud tops near 30,000 feet. The GOES-10 visible image for 0900 (2X magnification) continued to depict an extensive area of cloud cover over California and the accident site. The cloud features over the upset location showed signs of vertical development consistent with nimbostratus type clouds. 1.7.4 Weather Radar Information The closest Weather Surveillance Radar-1988, Doppler (WSR-88D) was located at the NWS San Joaquin Valley Office (KHNX) in Hanford, California, approximately 34 miles east of the accident site. The Level II archive data was obtained from the National Climatic Data Center (NCDC) and displayed on a Hewlett-Packard X-Station utilizing the National Transportation Safety Board McIDAS system. Composite Reflectivity The KHNX composite reflectivity image completed at 0904 (2X magnification) with the accident airplane's flight track that was obtained from the FAA National Track Analysis Program (NTAP). The image depicts the accident airplane's track across an area of very light intensity echoes in the range of 5 to 15 dBZ and approaching two general north-to-south oriented line of echoes. The upset location occurs on the western edge of the band of the first band. Base Reflectivity The KHNX WSR-88D images use 2.4- and 3.4- degree base reflectivity scans for 0859 at 4X magnification. The 2.4- degree elevation scan depicted the conditions under the accident airplane's flight track approaching the western edge of the band of echoes when the upset occurred. The conditions that encompassed the accident airplane's cruising altitude of 13,600 feet indicated that the aircraft was operating in echoes in the range of 5 to 15 dBZ for approximately 16 miles prior to the upset, or from approximately 0854. Echoes in the range of -10 to +10 dBZ, with temperatures below freezing, are typically associated with freezing drizzle, freezing rain, and large super cooled liquid water droplets (SLD) with reflectivities above 20 dBZ. Radar Summary for Hanford (HNX), 30 nm to the southeast A cell containing thunderstorms and intense rain showers was recorded at 0935. The cell was 3 nautical miles (nm) in diameter, centered at 175 degrees, 11 nm from HNX. An area of echoes, 5/10 coverage contained rain. The cell was 88 nm from 340 degrees to 164 degrees at 38 nm from HNX automated station. 1.7.5 In-Flight Weather Advisories The NWS issues in-flight weather advisories designated as Severe Weather Forecast Alerts (AWW's), Convective SIGMET's (WST's), SIGMET's (WS's), Center Weather Advisories (CWA's), and AIRMET's (WA's). In-flight advisories serve to notify en route pilots of the possibility of encountering hazardous flying conditions, which may not have been forecast at the time of the preflight briefing. The NWS issued a series of AIRMETs at 0645, which were current until 1300. The advisories pertinent to the route of flight were as follows: AIRMET Sierra update 2 was issued for mountain obscuration over portions of California and contained the area surrounding the accident location. The advisory warned of mountains occasionally obscured by clouds, fog, and mist. AIRMET Tango update 3 was issued for turbulence over portions of Washington, Oregon, California, Nevada, Arizona, Utah, and contained the area surrounding the accident location. The advisory warned of occasional moderate turbulence below 15,000 feet due to strong and gusty southerly to southwesterly low-level winds. The conditions were expected to develop southward and eastward through 1300, spreading into Idaho and western Montana, and the remainder of Utah and Arizona through 1900. The accident site was located within the limits of this advisory. AIRMET Zulu update 2 was current for portions of northern California, Oregon, Washington, Idaho, Montana, Nevada, coastal waters, and contained the area surrounding the accident location. The advisory warned of occasional moderate rime to mixed icing-in-clouds and in-precipitation between the freezing level and 20,000 feet. The freezing level was identified from 4,000 to 5,000 feet over the western portion of the area to 8,000 to 10,000 feet over the eastern portion. The conditions were expected to continue beyond 1300 through 1900, and spread southeastward. The accident site was located approximately 30 miles south of this advisory. There were no other severe weather forecast alerts, SIGMETs, or Center Weather Advisories issued for California on April 7, 2005. 1.7.6 Pilot Reports (PIREPs) The following pilot reports were recorded over central California within 120 miles of the accident site on April 7, 2005. The reports are in chronological order, and are narrative form instead of the standard code. Modesto (MOD) routine pilot report (UA); Over - 15 miles southeast of Modesto (MOD); Time - 0707; Flight level - 9,000 feet; Type aircraft - Cessna Caravan single engine turboprop (C208); Temperature - minus 1 degree C; Icing - light rime icing. Stockdale (SCK) routine pilot report (UA); Over - 40 miles east-northeast of Stockton VOR (ECA); Time - 0712; Flight level - 18,000 feet; Type aircraft - Boeing 737 commercial airliner (B737); Turbulence - moderate chop between 18,000 and 15,000 feet. Stockdale (SCK) routine pilot report (UA); Over - 20 miles northeast of Stockton VOR (ECA); Time - 0741; Flight level - 11,500 feet; Type aircraft - Boeing 737 commercial airliner (B737); Turbulence - light to moderate turbulence during descent between 13,000 and 11,500 feet. Modesto (MOD) routine pilot report (UA); Over - Modesto (MOD); Time - 0941; Flight level - 8,000 feet; Type aircraft - Piper Malibu single engine turboprop (PA46); Temperature - minus 2 degree C; Wind - from 260 degrees at 21 knots; turbulence - light chop; Icing - negative. 1.7.7 Preflight Weather Briefing The pilot called the Oakland Automated Flight Service Station (AFSS) between 0544 and 0550, at which time he obtained a preflight weather briefing for the route of flight. The pilot indicated he intended to leave around 0700 local time from Santa Rosa traveling to Scottsdale, and was planning on operating at 13,000 feet. The AFSS briefer provided a synopsis of the current conditions indicating that a front extended along the coast of northern California with scattered precipitation ahead of it. He stated that there was a line of scattered precipitation from Salinas to Merced, California, especially over the central valley. The AFSS briefer indicated that advisories were current for occasional moderate turbulence below 15,000 feet, occasional moderate rime ice in any precipitation below flight level 200, the freezing level was about 6,000 feet, and that some higher terrain may be obscured by clouds. The briefer provided information for several locations along the proposed route of flight, which included a report in the immediate vicinity of the accident site for the Lemoore (KNLC), which indicated broken clouds between 3,000 to 5,000 feet, and overcast conditions between 5,000 and 6,000 feet. The weather over Scottsdale was clear. The AFSS briefer summarized the conditions and indicated that general VFR (visual flight rules) conditions would prevail for the route. The briefing ended with the pilot saying, "Sounds good.
the pilot's in-flight loss of control due to spatial disorientation and a likely accumulation of airframe ice that led to a high speed descent and a structural breakup once the aerodynamic forces exceeded the strength limits of the structure. A factor in the accident was the pilot's lack of experience and training in instrument flight conditions.
Source: NTSB Aviation Accident Database
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