CHI08FA133

The accident occurred while the airplane was operating in instrument meteorological conditions on an instrument flight plan. While enroute, the pilot had requested a higher cruise altitude on two separate occasions in an attempt to climb above the cloud tops. The final assigned cruise altitude was 9,000 feet. Infrared satellite imagery indicated that the cloud tops were in excess of 9,700 feet near the accident site. Radar track data showed the airplane level at 9,000 feet when it made a 35-degree right turn off the intended route of flight to an east-northeast course. About 60 seconds later, the airplane made a left turn to a north heading followed by a right spiraling descent. During the final 40 seconds of radar data, the airplane descended from 9,100 to 7,800 feet. The calculated descent rate incrementally increased to approximately 4,200 feet per minute. The increasing spiral course and rapid rate of descent was consistent with a pilot experiencing spatial disorientation. According to air traffic control data, the pilot made no distress call and did not indicate if the airplane had experienced any mechanical difficulties. The pilot also did not report any accumulation of structural ice, although there was a high potential for icing conditions at the cruise altitudes used during the accident flight. The distribution of the wreckage was consistent with an in-flight breakup at low altitude. The on-scene investigation revealed no pre-impact mechanical malfunctions or anomalies that would have prevented the normal operation of the airplane or its systems.

History of flight

On May 12, 2008, at 1105 eastern daylight time, a Beech V35 Bonanza, N7947M, operated by an instrument rated private pilot, was destroyed on impact following an in-flight breakup while in cruise flight near Bristol, Ohio. Instrument meteorological conditions existed at the airplane's assigned cruise altitude and marginal visual meteorological conditions prevailed at the surface. The personal flight was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 91 while on an instrument flight plan. The pilot and his passenger were fatally injured. The flight departed Tri-State/Ferguson Field (KHTS) in Huntington, West Virginia, at 1018 and was enroute to Greater Rochester International Airport (KROC), Rochester, New York.

At 0747, the pilot contacted the Washington Automated Flight Service Station to obtain a standard weather briefing and to file an instrument flight plan. The pilot initially stated that his planned cruise altitude would be 7,000 feet. The weather briefer informed the pilot that there was an active icing advisory for moderate icing between the freezing level and 20,000 feet. The briefer told the pilot that the freezing level at the departure and destination airports was approximately 6,000 feet and 5,000 feet, respectively, and that the cloud tops were approximately 15,000 feet. The briefer issued several pilot reports of icing conditions, consisting of light rime and light clear, that existed along the intended route of flight. The pilot was also told that instrument meteorological conditions, consisting of light precipitation and low ceilings, prevailed along his intended route of flight and that there was an active advisory for moderate turbulence below 15,000 feet. The pilot then filed a flight plan from KHTS to KROC with a cruise altitude of 5,000 feet.

According to Federal Aviation Administration (FAA) air traffic control data, at 1009 the pilot was issued an instrument flight rules (IFR) clearance from KHTS to KROC. At 1018, the flight departed KHTS on runway 30 and proceeded north-northeast enroute toward KROC. At 1023, the flight was cleared to the filed cruise altitude of 5,000 feet. At 1028, the pilot reported being near the cloud tops at 5,000 feet and requested a higher cruise altitude. The flight was subsequently cleared to 7,000 feet. During the climb, the pilot reported that the outside temperature at 5,000 feet was 0-degrees Celsius and that the cloud tops were at 5,700 feet.

At 1042:02 (hhmm:ss), the pilot established radio contact with Indianapolis Air Route Traffic Control Center's (ARTCC) Parkersburg Sector. The airplane continued north-northeast at 7,000 feet. At 1050:29, the pilot stated, "... can we try going up two or three hundred feet? I think we're right in the tops where we are." The air traffic controller subsequently cleared the pilot to climb to 9,000 feet. At 1055:27, aircraft radar track data showed the airplane level at 9,000 feet on a north-northeast course.

At 1055:49, the pilot was told to change to another Indianapolis ARTCC radio frequency. At 1056:46, the pilot established radio contact with Indianapolis ARTCC's Columbus Sector and was given the local altimeter setting. At 1056:55, the pilot acknowledged the local altimeter setting. There were no additional communications received from the accident pilot.

At 1102:00, the airplane made a 35-degree right turn to the east-northeast at 9,100 feet. At 1103:42, the airplane made a left turn to a north heading. The airplane then entered a right spiraling descent. During the next 40 seconds, the airplane descended from 9,100 to 7,800 feet. The calculated descent rate incrementally increased to approximately 4,200 feet per minute. At 1104:22, the airplane's altitude was last reported at 7,800 feet. At 1104:32, a final radar return was recorded without any altitude information.

Personnel information

According to FAA records, the pilot of N7947M, age 65, held a private pilot certificate with airplane single engine land, instrument airplane, and lighter-than-air balloon ratings. The instrument rating was issued on September 20, 2003. The pilot's last aviation medical examination was completed on May 18, 2007, when he was issued a third-class medical certificate with the limitation that he wear corrective lenses. A search of FAA records showed no accident, incident, enforcement, or disciplinary actions.

The pilot's most recent logbook entry was dated May 10, 2008. He had accumulated 1,012.9 hours total flight time, of which 968.1 hours were as pilot-in-command. He had accumulated 784.7 hours in single-engine airplanes, 228.2 hours in lighter-than-air balloons, 51.5 hours at night, 137.5 hours in actual instrument conditions, and 45.0 hours in simulated instrument conditions. He had accumulated 42.1 hours in a Beech V35 airplane.

The pilot had flown 156.5 hours during the past year, 27.1 hours during the prior 6 months, 14.7 hours during previous 90 days, and 8.1 hours during the prior 30 days. The pilot had not flown during the 24 hour period before the accident flight.

His last flight review was completed on September 27, 2007, in a Piper PA-28 airplane. His last instrument proficiency check (IPC) was completed on October 27, 2007. Subsequent to the IPC, he had logged 1 instrument approach and 2.9 hours of actual instrument time.

Aircraft information

The accident airplane was a 1966 Beech V35 Bonanza, serial number (s/n) D-8256. The Bonanza was a low wing, all-metal, single-engine, V-tailed, four-place monoplane. The airplane had a certified maximum takeoff weight of 3,400 lbs. The airplane was equipped for operation under instrument flight rules (IFR). The airplane was not equipped or certified for flight in icing conditions. A Teledyne Continental Motors model IO-520-B reciprocating engine, s/n 121048-6-B, powered the airplane. The 285-horsepower engine provided thrust through a Hartzell model PHC-C3YF-1RF, s/n EE5417B, constant speed, three-blade, metal propeller.

The accident airplane was issued a standard airworthiness certificate on August 9, 1966. The pilot purchased the airplane on September 27, 2007. The airframe and engine had a total service time of 2,616 hours. The engine had accumulated 1,301 hours since its last overhaul, which was completed on March 10, 1977. The propeller had accumulated 177 hours total time after being installed on March 10, 2006. The last annual inspection was completed on April 7, 2007, at 2,525 hours total service time. On March 22, 2007, tests on the static system, altimeter system, automatic pressure altitude reporting system, and transponder were completed.

The airplane was topped off with 29.8 gallons of 100 low-lead aviation fuel at the departure airport. The accident occurred during the first flight after being refueled. A post-accident inspection of the departure airport's fuel sources did not reveal any water or particulate contamination.

On May 10, 2008, the pilot requested the use of the departure airport's 28-volt ground power unit (GPU) because of a depleted aircraft battery. The aircraft was equipped with a single 12-volt Gill G-35 battery. According to several witnesses, the battery "exploded" as the pilot attempted to start the engine with external power attached. A local mechanic then replaced the damaged battery and repaired the airframe's battery box. No electrical system anomalies or malfunctions were noted after the completed repairs. The accident occurred during the first flight after the battery maintenance was performed.

A review of the maintenance records found no history of unresolved airworthiness issues.

Meteorological information

The nearest weather reporting station was located at Zanesville Municipal Airport (KZZV) about 18 miles north-northwest of the accident site. The airport was equipped with an Automated Surface Observing System (ASOS).