NTSB Factual Report

HISTORY OF FLIGHT

On July 31, 1998, at 2022 central daylight time (cdt), a Navion A, N8991H, operated by a private pilot, was destroyed when while cruising at low altitude, the airplane struck a power line, and subsequently impacted the terrain and an interstate highway guard rail, 2 miles south of Coloma, Wisconsin. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being operated under 14 CFR Part 91. The was no flight plan on file. The pilot was fatally injured. The cross- country flight originated at Kankakee, Illinois, and was en route to Oshkosh, Wisconsin.

A witness at the Greater Kankakee Airport, Kankakee, Illinois, said that the pilot landed at Kankakee, at 1545 cdt. He had his airplane serviced with 32.7 gallons of 100 low lead aviation fuel. The pilot had to delay his departure from Kankakee, en route to Oshkosh, because Wittman Regional Airport did not open to arriving aircraft until 1930 cdt. The witness did not see the pilot take off, but estimated that it was approximately 1800 when the pilot departed Kankakee.

A witness at Reabe Spraying Service, Plainfield, Wisconsin (15 miles north of Coloma), said that he observed the airplane flying southbound at 200 to 300 feet above the ground. The airplane appeared to be following Interstate 39. When the witness first saw the airplane approaching from the north, he noticed that the landing gear was down. As the airplane approached the intersection where Wisconsin State Highway 73 crosses Interstate 39, the witness observed the landing gear go up. Once the airplane passed the intersection, the witness saw the landing gear extended again. The airplane continued southbound, following Interstate 39, until the witness lost sight of it. The witness said that during the time he observed the airplane, the airplane's engine sounded as if it were running in fine tune and that there were no rough spots, or "cutting out" sounds.

Several witnesses traveling in automobiles northbound on Interstate 39, in the vicinity of Coloma, Wisconsin, observed the airplane flying southward, following the Interstate, at an altitude of 100 to 175 feet above ground level. One witness said that the airplane looked as if it were landing. Another witness said that the airplane's landing gear was "down, and in a locked position." The witness said that he saw the airplane "hit the power lines, and visual arcing of the power lines, as the plane tumbled to the ground."

At 2022 cdt, the Waushara County, Wisconsin, Sheriff's Department received several telephone calls reporting an airplane crash on Interstate 39, south of Coloma.

PERSONNEL INFORMATION

The pilot held a Private Pilot certificate with an airplane, single-engine land rating. According to airman records obtained from the Federal Aviation Administration (FAA), the pilot had approximately 3,500 hours total flight time. A personal log maintained by the pilot showed that he had 292 hours in the Navion A.

Another personal logbook indicated that the pilot had successfully completed a biennial flight review on August 28, 1996.

AIRCRAFT INFORMATION

The airplane was registered to London Flyers, Incorporated, of Bowling Green, Kentucky. The company is co-located at the pilot's home address. At the time of the accident, the airplane was being used for pleasure.

The airplane logbook indicated that an annual inspection was performed on December 10, 1997. The airframe time recorded at the time of the annual inspection was 2,243.5 hours.

WRECKAGE AND IMPACT INFORMATION

The NTSB on-site investigation began on August 1, 1998, at 0605 cdt.

The accident site was located in the median, 10 feet west of the northbound lane of Interstate 39/U. S. Highway 51, and 2.5 miles south of Coloma, Wisconsin. The airplane main wreckage was found resting upright on a guard rail, and oriented on a 097 degree magnetic heading.

Approximately 338 feet north-northwest of the main wreckage were a set of east-west running power lines. Following the accident, the top ground wire and the top southernmost power line were severed over the southbound lane of the interstate. At the time the on-site investigation began, the power line and ground line had been repaired.

Approximately 288 feet south of where the power lines were severed, on a 123 degree magnetic heading, were two parallel- running ground scars, approximately 5 feet apart, and running along a 155 degree magnetic heading to the airplane's main wreckage. The east ground scar was 18 feet long, 3 feet at its widest point, and 12 inches deep. The west ground scar was 54 feet long, 10 inches at its widest point, and 8 inches deep.

The airplane's nose wheel was approximately 25 feet from the beginning of the east ground scar. The gear strut was broken aft, just above the fork. One side of the wheel rim showed a 2- inch wide melted area on the edge at the tire.

The airplane's left wing tip was approximately 6 feet left of the beginning of the east ground scar. It was broken along the longitudinal rivet line and bent outward.

One of the propeller blades rested due south of the main wreckage, approximately 58 feet away. The blade showed torsional bending, chordwise scratches, and tip curling.

The airplane's main wreckage consisted of the fuselage, both wings, empennage, main landing gear, engine, cowling, and propeller, less the one blade located south of the wreckage.

The airplane's spinner was crushed inward and broken open. The remaining propeller blade showed torsional bending and chordwise scratches. The airplane's cowling was broken downward and separated just forward of the firewall. The airplane's engine was broken at the upper mounts and canted downward 75 degrees from the longitudinal axis. The bottom of the right forward fuselage was crushed inward and bent aft.

The airplane's right wing was intact. A 31-inch section of the right wing's leading edge, beginning at the wing root and running outward, was crushed aft to a depth of 9 inches, and bent downward. The right main landing gear was pushed upward through the upper wing skin. A 23-inch wide and 20 inch long "L-shaped" tear in the upper wing skin was observed, 27 inches outboard of the root and 40 inches aft of the leading edge. A 25 degree outward buckle in the upper wing skin was also observed in this area. The airplane's main fuel tank was intact and appeared full of fuel. The right main landing gear was partially extended approximately 20 degrees. The main gear strut was twisted outward approximately 80 degrees. The airplane's right flap was extended approximately 20 degrees. There was a 15 degree downward bend in the flap, approximately 41 inches outboard of the wing root. No damage was observed to the airplane's right aileron or right wing tip. Flight control continuity to the right aileron was confirmed.

The airplane's cockpit was intact. The forward windscreen and sliding canopy were undamaged. The canopy was detached from its sliding rails and was found resting on the left aft cockpit wall.

Several small longitudinal running scrapes were observed along the top of the canopy, beginning near the top center and running aft. The forward instrument panel was bent forward and in approximately 7 inches at the center. A 1/4 inch diameter antennae located just forward and left of the windscreen was bent aft and kinked in several places. The airplane's right side fuselage, 43 inches aft of the right wing's root trailing edge, was bent inward and buckled. The airplane's left side fuselage, 37 inches aft of the left wing's root trailing edge, was bent inward and buckled. A 35 inch long, 6 strand (3/16 inch diameter strands) cable was found wrapped around the base of the radio antennae located on the top center of the aft fuselage, behind the cockpit.

The airplane's empennage was intact. The left and right horizontal stabilizers and elevator were undamaged. Flight control continuity to the elevator was confirmed. The airplane's vertical stabilizer and rudder showed no damage. Flight control continuity to the rudder was confirmed.

The airplane's left wing showed a 40 degree upward bend and skin tear, 32 inches outboard of the wing root. The outboard wing section, 107 inches outboard of the wing root, was broken along the top longitudinal rivet line and bent downward 45 degrees. The leading edge of the left wing, beginning at the fracture, 107 inches outboard of the wing root, was bent upward and crushed in approximately 27 inches. The crush damage proceeded outward from the fracture to the wing tip rivet line. A 16 inch wide flat dented area and wing skin tear were located in the leading edge of the left wing just inboard of the wing tip rivet line. Prairie grass similar to that found in the median area in the vicinity of the accident site, was found embedded in the sin tear. The left wing tip was broken off along the longitudinal rivet line. The left main landing gear was partially extended approximately 70 degrees. The main gear strut was bent aft and twisted outward approximately 90 degrees. The airplane's left flap was extended approximately 20 degrees. No damage was observed to the left aileron. Flight control continuity to the left aileron was confirmed.

No anomalies were found with the airplane's systems at the accident site. The airplane's engine was retained for further testing.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy of the pilot was conducted on August 2, 1998, by the Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison Medical School, Madison, Wisconsin, for the Waushara County Coroner. The autopsy revealed "sufficient coronary atherosclerosis and emphysema to potentially cause problems."

The results of FAA toxicology testing of specimens from the pilot were negative for all tests conducted.

TESTS AND RESEARCH

The airplane's engine was examined at Wittman Regional Airport, Oshkosh, Wisconsin, on August 27, 1998. The examination revealed no anomalies.

ADDITIONAL INFORMATION

A party to the investigation was the Federal Aviation Administration Flight Standards District Office, Milwaukee, Wisconsin.

All wreckage was released and returned to Myers Aviation, Incorporated, Oshkosh, Wisconsin.

NTSB Probable Cause

Failure of the pilot to maintain proper altitude, and his failure to maintain adequate visual lookout to see and avoid obstructions. The transmission wire was a contributing factor.