Aviation Accident Summaries

Aviation Accident Summary LAX99FA104

COALINGA, CA, USA

Aircraft #1

N125TW

Beech 95-B55

Analysis

The pilot and passenger had flown to northern California for dental work to be performed on the pilot. On the return trip they were receiving VFR advisories from ATC. They were maintaining VFR on top at 14,500 feet msl. A voice thought to be the passenger, who was a rated pilot, transmitted 'we're in big trouble up here' followed by other incomplete or unreadable transmissions. The airplane was lost from radar and radio contact. The wreckage was located in mountainous terrain. The airplane had collided with terrain while in a near vertical attitude. The pilot had obtained a preflight weather briefing prior to flight, and VFR was not recommended. A formal weather study indicated that the airplane most likely flew into clouds. Conditions were conducive for light to moderate rime icing in clouds at the airplane's flight altitude. The time was 11 minutes before official sunset in cloudy conditions.

Factual Information

HISTORY OF FLIGHT On February 18, 1999, about 1745 hours Pacific standard time, a Beech 95-B55, N125TW, was destroyed in an in-flight collision with mountainous terrain near Coalinga, California. The private pilot and pilot rated passenger were fatally injured. The personal flight was being operated under 14 CFR Part 91 and no flight plan was filed. The nearest weather reporting facility is 33 miles to the east; however, local area residents reported instrument meteorological conditions with rain and wind existed near the accident site. The flight originated at Sacramento, California, at 1649 on the day of the accident and was destined for Fullerton, California. The pilot and passenger had flown to northern California for dental work to be performed on the pilot. On the return trip they were receiving VFR advisories from ATC. They were maintaining VFR on top at 14,500 feet msl. A voice thought to be the pilot rated passenger transmitted "we're in big trouble up here" followed by incomplete and unreadable transmissions. The aircraft was lost from radio and radar coverage at 14,500 feet msl, about 20 miles southeast of the Panoche VOR. Search efforts were initiated and the wreckage was subsequently found February 19 near Santa Rita Peak, in San Benito County. The Federal Aviation Administration (FAA) coordinator made a request for radar data from NAS Lemoore. The tape was pulled, viewed, and then inadvertently erased following a breakdown in tape safeguarding procedures. Prior to departure from the Sacramento Executive Airport, the pilot purchased 58.0 gallons of fuel and obtained a preflight weather briefing from the FAA Rancho Murrieta flight service station for the route of flight. According to the briefing VFR flight was not recommended. PERSONNEL INFORMATION At the private pilot's last third-class flight physical on February 26, 1998, he reported a total flight time of 2,500 hours. The pilot's logbook was not recovered. AIRCRAFT INFORMATION Examination of the airframe logbook revealed that an annual inspection had been performed on the aircraft February 14, 1999. At the inspection it was noted that the aircraft had accumulated 2,846.6 total flight hours. There were no time recording devices recovered from the wreckage. Both engine logbooks revealed 179.4 hours had accumulated since major overhaul at the time of the last annual inspection. Copies of the logbook records are attached to this report. According to a friend and hangar neighbor of the pilot, the Bendix FCS-810 autopilot had been inoperative for some time. They had removed components from his aircraft to see which of the components were not working, and were unsuccessful in finding the problem. According to AlliedSignal, Ft. Lauderdale, Florida, an autopilot system component had been repaired at their facility December 7, 1998. According to logbook information, the last 24-month ATC transponder test (FAR 91-413) and static/altimeter test (FAR 91-411) was performed on March 16, 1995. METEOROLOGICAL INFORMATION The nearest weather-reporting site is NAS Lemoore, about 33 miles east of the accident site. At 1755, they were reporting: wind 340 degrees at 11 knots; visibility 4 miles in haze; broken clouds at 10,000 feet; overcast at 12,000 feet; temperature 61 degrees Fahrenheit; dew point 52 degrees Fahrenheit; altimeter 30.06 inHg. According to a Safety Board meteorology report, the visible satellite image for 1730 showed that the accident location was approximately on the northern edge of a west-southwest, east-northeast band of clouds. The visual appearance of the cloud elements in the line indicated that there might have been scattered convective elements in the line. Infrared temperature data for 1730 and 1745 showed that cloud top temperatures decreased in vicinity of the accident area from -13 degrees to near -21 degrees Celsius. The Oakland and Vandenberg upper air soundings indicated that the height range between these temperatures were probably from a little above 15,000 feet to around 22,000 feet. Airmets for turbulence and mountain obscuration were in effect for the area, with pilot reports of icing in the Fresno area. According to a Safety Board sun and moon program the sun was 2 degrees above the horizon or 11 minutes from official sunset in cloudy conditions. WRECKAGE AND IMPACT INFORMATION The Safety Board examined the wreckage on scene and after recovery. The accident site was located at 36 degrees 23.75 minutes north latitude by 120 degrees 38.01 minutes west longitude, about 3,500 feet msl. The airplane wreckage was observed straddling a granite rock outcropping from a near vertical attitude as evidenced from wing and fuselage accordioning signatures. The wreckage was contained in a 50-foot circle with negligible scatter. There was no postcrash fire damage; there was evidence of fuel hydraulicing of the fuel cell areas. The entire airplane was accounted for at the site. Control continuity was not possible due to the fragmented condition of the structure. The propellers were severed from the engine crankshaft flanges with some tortional bluing observed at the fracture point. The propeller blades revealed leading edge damage, trailing edge "S" bending, and chordwise striations with loss of blade tips. MEDICAL AND PATHOLOGICAL INFORMATION On February 22, 1999, the San Benito County Sheriff/Coroner performed an autopsy on the pilot. During the procedure samples were obtained for toxicological analysis at the FAA Civil Aeromedical Institute in Oklahoma City, Oklahoma. According to the report, the results were negative for carbon monoxide, cyanide, and drugs. The analysis was positive, all detected in the kidney, for ethanol (35 mg/dL, mg/hg), isobutanol (57 mg/dL, mg/hg), methanol (530 mg/dL, mg/hg), n-propanol (54 mg/dL, mg/hg), and acetaldehyde (4 mg/dL, mg/hg). Ethanol was also detected in the muscle at 10 mg/dL, mg/hg. ADDITIONAL INFORMATION Oxygen bottles and masks without mikes were found in the wreckage. It could not be determined whether oxygen was being used, or if the bottles had oxygen available. The wreckage was released to the insurance company representative on April 21, 1999.

Probable Cause and Findings

the pilot's inadvertant visual flight into instrument meteorological conditions.

 

Source: NTSB Aviation Accident Database

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