CEN09LA409

A witness observed the airplane flying at a low altitude when it suddenly descended nose first into terrain. The postaccident examination revealed that the airplane collided with a 70-foot high power line that crossed over the road. No preimpact mechanical malfunctions or failures were found that would have prevented normal operation of the airplane.

HISTORY OF FLIGHT On July 3, 2009, at 1329 central daylight time, a Cessna 172, N8138B, was substantially damaged when it impacted terrain near Latimer, Iowa. The pilot was fatally injured. The airplane was registered to and operated by the private pilot, under the provisions of 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed for the flight, which was operated without a flight plan. The local flight had departed from the Hampton Municipal Airport (KHPT), near Hampton, Iowa, at an unconfirmed time. According to the pilot's wife, the pilot had provided airplane rides for some friends earlier in the day, departing from KHPT and flying over Iowa Falls and Sheffield, Iowa. Shortly before the accident, the airplane over flew their residence as a signal to her that he was done flying and needed to be picked up at the airport. The pilot's wife proceeded to drive east on County Highway 25 (190th Street) toward the airport. As she was driving, she observed the airplane in her rear-view mirror following her car at a low altitude before it suddenly descended nose first into the ground. A witness reported that she was working in her backyard when she heard two impact sounds emanate from the road in front of her residence. She remarked that her view to the south and west was obscured by her house and the trees that bordered 190th street and the west property line. After hearing the sound of an impact, her children immediately called for her to come to the front yard where she saw the wreckage on the road. She noted that from her original position in the backyard she did not hear the sound of an airplane flying in the area. She also remarked that the terrain surrounding her residence consisted of open agricultural fields. PERSONNEL INFORMATION According to Federal Aviation Administration (FAA) records, the accident pilot, age 44, held a private pilot certificate, issued on August 15, 2002, with an airplane single-engine land rating. His last airman medical examination was completed on July 3, 2007, when he was issued a third-class medical certificate with the limitation that he possess corrective lenses for near vision. A search of FAA records showed no accident, incident, enforcement, or disciplinary actions. The most recent pilot logbook entry was dated March 21, 2009. At that time, the pilot had accumulated 180.8 hours total flight time, of which 153.6 hours were as pilot-in-command. He had accumulated 180.8 hours in single-engine airplanes, 16.2 hours at night, and 3.3 hours in simulated instrument conditions. He had flown 25.4 hours in the past 2 years, 8.8 hours during the past year, 1 hour during the prior 6 months, and no hours during previous 90 days. The pilot's most recent flight review was completed in the accident airplane on November 29, 2008. AIRCRAFT INFORMATION The accident airplane was a 1957 Cessna model 172, serial number (s/n) 29938. The airplane was a high wing, all-metal, single-engine, four-placemonoplane. The airplane had a certified maximum takeoff weight of 2,200 pounds. A 145-horsepower Continental Motors model O-300-A reciprocating engine, s/n 12691-D-6-A, provided thrust through a McCauley model 1A170, s/n 55994, fixed pitch, two-blade, metal propeller. The accident airplane was issued a standard airworthiness certificate on June 1, 1957. The airframe and engine had a total service time of 3,144 hours at the time of the accident. The engine had accumulated 791.5 hours since its last major overhaul. The last annual inspection was completed on May 3, 2008, at 3,122 hours total service time. A postaccident review of the maintenance records found no history of unresolved airworthiness issues. METEOROLOGICAL INFORMATION The closest weather reporting facility was at Iowa Falls Municipal Airport (KIFA), Iowa Falls, Iowa, located about 23 miles south of the accident site. The airport was equipped with an automated surface observing system (ASOS). At 1335, the KIFA ASOS reported the following weather conditions: Wind 170 degrees at 3 knots; visibility 10 miles; sky clear; temperature 25 degrees Celsius; dew point 15 degrees Celsius; altimeter setting 30.12 inches of mercury. WRECKAGE AND IMPACT INFORMATION The airplane collided with an east/west asphalt road about 5 miles northeast of Latimer, Iowa. The wreckage debris path was orientated on an easterly heading and was about 300 feet long. There were 70-foot high power lines that crossed over the road. One of nearby towers had a displaced wind dampener which was consistent with one of the power lines being stretched beyond its design limits; however, there were no broken power lines. The nose landing gear was found about 100 feet west of the north/south power lines. The upper portion of the nose landing gear fork exhibited multiple striations in the metal casting perpendicular to the strut alignment, consistent with a collision with a power line. The main wreckage was located about 150 feet east of the power lines along the observed direction of flight. The main wreckage consisted of the entire airframe. The airplane was found inverted resting on the upper fuselage. The forward fuselage and engine was crushed/displaced rearward to the forward cabin door frame, consistent with a near vertical impact. All flight control surfaces remained attached to their respective airframe hinges. Flight control cable continuity was confirmed from the respective flight control surfaces to the forward cabin. The wing flaps were fully retracted. The cockpit throttle control was about 1-inch from full throttle, the mixture control was full rich, and carburetor heat control was not engaged. The engine primer was full forward and locked. The magneto switch was selected to both magnetos. There was fuel present in the airplane fuel tanks and the cockpit fuel selector handle was positioned to draw fuel from both tanks. The fuel strainer bowl contained fuel and the filter screen was free of any contamination. Theengine remained attached to the airframe by control cables. The engine mounts were separated from the crankcase and the engine oil pan was fractured exposing the internal engine components. A visual inspection confirmed that all internal engine components remained connected, including the crankshaft, connecting rods, pistons, and camshaft interfaces. The crankshaft was displaced rearward into the crankcase, which prevented its rotation due to interference with the case. The magnetos, starter, and generator remained attached to the engine. Both magnetos produced spark on all leads when rotated by hand. The upper spark plugs were removed and exhibited normal wear signatures. The propeller remained attached to the propeller flange; however, the crankshaft had fractured immediately aft of the propeller flange, separating the propeller assembly from the engine. The fracture surface appeared consistent with an overstress failure. The propeller spinner was crushed/flattened, consistent with a near vertical impact. One propeller blade was bent aft about 30-degrees and exhibited chordwise scratches on its face. The other propeller blade was curled aft near the tip and had leading edge polishing. The postaccident investigation revealed no preimpact mechanical malfunctions or failures that would have prevented normal operation of the airplane. MEDICAL AND PATHOLOGICAL INFORMATION On July 4, 2009, an autopsy was performed on the pilot by the Iowa State Medical Examiner Office located in Ankeny, Iowa. The pilot's cause of death was attributed to multiple blunt force injuries sustained during the accident. The FAA Civil Aerospace Medical Institute toxicology tests were negative for all screened substances, including carbon monoxide, cyanide, ethanol, and drugs.