IAD96LA063

The airplane was cruising at 13,000 feet msl in IMC conditions when the pilot requested and received clearance to descend to 9,000 feet to avoid flying in the clouds. Radar data indicates that moments later the airplane made a turn to the right and descended abruptly, then disappeared from radar and radio contact. Witnesses reported that there were severe storms in the area, including hail, heavy rain, high winds, thunder, and lightning at the time of the accident. Analysis of satellite imagery indicated a temperature of -12 degrees at 9,000 feet msl and a freezing level at 4,700 feet msl. AIRMET Zulu Update 2 for icing conditions pertained to the route of flight, and there were numerous pilot reports of turbulence and icing conditions in the vicinity of the accident. There was no record that the pilot was advised by FSS of the AIRMET information about the icing conditions. ATC records indicated that the pilot had encountered severe turbulence at altitudes below 13,000 feet during the 1 1/2 hours before the accident. According to the Owners Manual, the airplane must not be exposed to icing encounters of any intensity.

History of flight

On April 16, 1996, at 1605 eastern daylight time (EDT), a Glasair GL20, N518EC, piloted by the registered owner/operator, impacted terrain in a wooded area near Rocky Mount, Virginia. The certificated private pilot and the passenger were fatally injured. The airplane was destroyed. Visual meteorological conditions prevailed and an IFR flight plan was filed. The personal flight was conducted under 14 CFR 91 and originated in Greenville, South Carolina, at 1456 EDT. The intended destination was Leesburg, Virginia.

According to Air Traffic Control (ATC) records, at 1449 EDT the pilot requested and received an IFR clearance for a flight to Virginia. Records also indicated that at 1505 EDT, ATC cleared the pilot to climb to 9,000 feet mean sea level (msl.) Three minutes later, the pilot requested permission to climb to 11,000 feet msl, due to severe turbulence. At 1510 EDT, ATC issued a clearance to climb to 11,000 feet msl. At 1512 EDT, the pilot requested and received permission to climb to 12,000 feet msl.

At 1529 EDT, Atlanta Air Route Traffic Control Center (ZTL ARTCC) asked the pilot to verify that the airplane was level at 12,000 feet msl. The pilot responded that the airplane was at 12,400 feet msl due to turbulence, and he requested a higher assigned altitude. At 1530 EDT, the flight was cleared to 13,000 feet msl. At 1532 EDT, the pilot reported that the flight was smooth.

At approximately 1553 EDT, the pilot advised ATC that he was encountering clouds and he requested a lower altitude, in an attempt to stay out of icing conditions. At 1556 EDT, ATC cleared the pilot to descend to 11,000 feet msl. Three minutes later, the pilot requested lower, due to "...heavy clouds." At 1602 EDT, ATC issued instructions to the pilot received clearance to 9,000 feet msl and the controller issued a Pilot Report (PIREP) made by another airplane of moderate turbulence.

At 1605:05 EDT, the Air Route Traffic Control Center (ARTCC) controller noted that the airplane was descending through 9,000 feet msl, and advised the pilot to maintain 5,000 feet msl. At 1605:16 EDT, the controller issued a low altitude alert and stated "...check your altitude immediately, I show you at four thousand four hundred [feet msl] the minimum vectoring altitude in your area is five thousand [feet msl.]" At 1605:33 EDT, the controller stated "Glasair eight echo charlie radar contact is lost." There were no further radio transmissions from the pilot.

According to a Federal Aviation Administration (FAA) Air Safety Inspector, a witness reported that between the hours of 1600 EDT and 1610 EDT,"...heard wind begin to blow...the noise sounded like an airplane...immediately after the noise the wind started to blow very strong-much more than normal...the storm lasted approximately 20 minutes. Hail only lasted a minute or so." Other witnesses in the area reported severe storms including strong wind, heavy rain, hail, thunder and lightning at the time of the accident.

The airplane impacted terrain during the hours of daylight at 37 degrees, 03 minutes north latitude and 80 degrees, 01 minute west longitude. FAA statements, the meteorological data study, radar data study, and excerpts from the FAA ATC package are appended.

Personnel information

The pilot held a private pilot certificate with single engine land rating. He also held an instrument airplane rating. According to the pilot's log book, he had accumulated over 1628 hours of total flight time, including more than 20 hours of flight time in actual instrument conditions. He had completed an Instrument Competency Check (ICC) on December 5, 1995. The last recorded actual instrument time in the pilot's log book was dated June 1, 1995. The pilot held a valid FAA medical certificate, with limitations to wear corrective lenses, which was issued on July 25, 1995.

Aircraft information

The Glasair GL20 airplane, serial number 518, was equipped with a Lycoming O-320-D1A engine, serial number L-12759-39AC. At the time of the accident, according to the airplane's tachometer, the airplane had accumulated 1145 hours of flight time. There were no maintenance records available.

Meteorological information

At 1550 eastern daylight time, Roanoke Municipal Airport, located about 12 nautical miles north of the accident site issued the following observation:

Sky condition, 4800 feet scattered estimated ceiling 13,000 feet overcast; visibility, 20 miles in light rain showers; temperature, 52 degrees Fahrenheit (F); dew point, 33 degrees F; winds out of 270 degrees at 15 knots gusting 30 knots; and altimeter, 29.75 inches Hg.

Witnesses reported very strong winds, heavy rain, hail, thunder and lightning in the Rocky Mount area, at the time of the accident.

Wreckage and impact information

The airplane impacted terrain in a wooded area, and the wreckage was oriented on a southerly heading. All of the airplane structure and flight control groups were located at the accident site. The empennage was separated from the main fuselage. Flight control continuity was confirmed The landing gear was found in the up position and the flaps were in the retracted position.

According to the Textron Lycoming representative, the engine and the propeller assembly were "...buried in soft soil." One propeller blade was bent aft under the engine, while the other propeller blade was not damaged. Examination of the engine revealed it was intact, and all the accessories were attached. The four cylinders were attached and secured to the crankcase. There was no evidence of uncontained internal engine components. The propeller was manually rotated, which resulted in the operation of the cylinder valves, confirmation of compression in each cylinder, and confirmation of both magnetos spark-producing capability. The carburetor was fractured at the mount flange. Examination of the carburetor revealed the venturi and main nozzles were intact and clear. The fuel inlet and carburetor bowl were clean. The vacuum pump rotated freely when turned by hand. Examination of the vacuum pump revealed the drive shaft, rotor and vanes were intact. Residual amounts of aviation fuel was found within the center fuel tank.

The examination of the wreckage revealed no evidence of preimpact mechanical malfunction/failure of the airplane or engine.

Medical and pathological information

A medical examination of the pilot was conducted by Dr. C. E. Swecker, Medical Examiner of Franklin County, Rocky Mount, Virginia, on April 17, 1996. Toxicological examination of the pilot was conducted by the FAA Civil Aeromedical Institute (CAMI), in Oklahoma City, Oklahoma, on July 23, 1996. Toxicological tests were negative for all screened drugs and substances.

Additional information

According to the National Transportation Safety Board radar study specialist, examination of the National Tracking Analysis Program (NTAP) primary and secondary radar data from Atlanta ARTCC revealed that at 1553 EDT, the airplane was established on an approximate heading of 030 degrees, at an altitude of about 12, 900 feet msl. At 1556 EDT, the radar data revealed that the airplane initiated a descent, then leveled off at 12,000 feet msl at about 1557 EDT. The radar data indicated that at 1559 EDT the airplane made heading change to approximately 040 degrees. At 1600:52 EDT the airplane descended to 10,700 feet msl. According to the radar data, at 1603:40 EDT the airplane's altitude decreased rapidly, and the airplane made a turn to the right. The last recorded radar return was 4,600 feet msl. A copy of the radar study specialist's report is appended.

According to the National Transportation Safety Board's meteorological study specialist, examination of satellite imagery indicated patchy marginal visual flight rules (MVFR) and isolated instrument flight rules (IFR) due to mountain obscuration fog a