History of Flight
On May 21, 2009, at 1254 eastern daylight time, a Thornton RV-6A experimental amateur-built airplane (N39JT) was destroyed when it impacted terrain while maneuvering shortly after takeoff from Plainwell Municipal Airport (61D) in Plainwell, Michigan. The private pilot and a pilot-rated passenger sustained fatal injuries. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed, and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight from Plainwell to Elkhart, Indiana, was originating at the time of the accident.
According to local authorities, the pilot and passenger were seen at a local Plainwell restaurant prior to the accident flight. Restaurant personnel stated that the pilot and passenger had flown up from Elkhart to have lunch and planned to return to Elkhart afterward. During conversation, the pilot mentioned that the flight from Elkhart took approximately 30 minutes and the airplane used 8 gallons of fuel. After lunch, the pilot and passenger left the restaurant.
Several witnesses observed different portions of the accident flight. A couple of witnesses reported seeing the airplane initially heading north after takeoff from 61D, then turning west. The airplane lost altitude and dropped approximately 20 feet. One witness stated the airplane "regained control." The airplane flew straight and then began a series of turns with changes in altitude. The airplane "barely cleared the trees" and entered a 45-degree bank left turn prior to impact with terrain. The witness stated, "…the plane dropped out of the air." The airplane descended below trees, impacted terrain, and was consumed by fire. Fire and rescue personnel arrived shortly thereafter.
Personnel Information
The pilot, age 76 and seated in the left seat, held a private pilot certificate with airplane single-engine land and instrument ratings. His most recent third-class medical examination was conducted on January 22, 2009. A review of his logbook revealed 868.9 total flight hours and 188.2 flight hours in the accident airplane. He had completed 1.6 hours in the preceding 90 days. His most recent flight review was conducted on September 24, 2008. According to a family member, the logbook may not have accurately reflected flight hours in the months preceding the accident; the family member stated he knew the pilot had flown more than 1.6 hours in the preceding 90 days.
The pilot-rated passenger, age 68 and seated in the right seat, held a private pilot certificate with airplane single-engine land and instrument ratings. His most recent third-class medical certificate was issued on May 27, 2008, with a limitation for corrective lenses. On his medical certification application, he reported 888 total flight hours and 30 hours in the last 6 months. His logbook was not located during the investigation.
Aircraft Information
The 2001 Thornton RV-6A, serial number 24470, was a low-wing, fixed tricycle gear, experimental amateur-built airplane owned and operated by the pilot. It was powered by a four-cylinder Lycoming O-360-A1A engine rated at 180 horsepower and equipped with a two-bladed propeller. The airplane was configured to carry two occupants and equipped with dual controls. The airplane logbooks were not located during the investigation. On October 10, 2008, the pilot's logbook showed an entry for a 0.4 hour flight with the remark, "Post annual [aircraft] check, OK."
Meteorological Information
At 1253, Kalamazoo/Battle Creek International Airport (AZO), located approximately 15 nautical miles south of the accident site, recorded wind from 220 degrees at 13 knots, gusting to 18 knots, visibility 10 statute miles, sky clear, temperature 26 degrees Celsius, dew point 10 degrees Celsius, and an altimeter setting of 30.13 inches of mercury.
Wreckage and Impact Information
Federal Aviation Administration (FAA) inspectors examined the accident site. The site was located approximately 1 mile east of 61D. The airplane came to rest upright in a field and was destroyed during impact and post-impact fire. The cockpit, right wing, and fuselage were destroyed due to thermal damage. The crankshaft propeller flange was separated from the crankshaft and displayed a 45-degree shear lip fracture surface. Both propeller blades displayed leading edge gouging, chordwise scratches, and blade polishing. Flight control continuity was established to the flight control surfaces. No pre-impact anomalies were noted with the airframe. The wreckage was recovered for further examination.
Medical and Pathological Information
The pilot had a Special Issuance of his FAA medical certificate due to a history of glaucoma controlled on medication and a partial lung obstruction not resulting in symptoms. Neither the pilot nor the passenger noted a history of heart disease or high blood pressure on their most recent applications. On those applications, the pilot's blood pressure was noted as 152/82 and the passenger's as 134/66.
Autopsies were conducted by Sparrow Hospital for the Allegan County Medical Examiner’s Office on May 22, 2009. Both occupants were noted to have coronary artery disease and a scar from a prior heart attack. The cause of death listed for both were multiple blunt force and thermal injuries. Specimens were retained for toxicological analysis by the FAA Civil Aeromedical Institute’s Forensic and Accident Research Center.
Toxicological tests for the pilot were negative for carbon monoxide, cyanide, alcohol, and all screened drugs. For the passenger, tests were negative for carbon monoxide, cyanide, and alcohol. An unspecified level of Atenolol was detected in the blood and urine; 0.089 (ug/ml, ug/g) of diphenhydramine was detected in the blood, and an unspecified level of diphenhydramine was detected in the urine. The source of blood submitted for toxicology testing was not noted, but the autopsy report indicated no cavity blood present. Atenolol is a beta blocker medication used to control high blood pressure or heart rate. Its use was not reported on his most recent medical certificate application.
Test and Research
On June 23, 2009, FAA inspectors examined the engine with the assistance of a local mechanic. The engine was damaged by impact and post-impact fire. The magnetos were removed and rotation was verified, but they could not be functionally tested. The crankshaft could not be rotated, and several thru-bolts were found broken in the crankcase. The oil appeared clean and free of contaminants. The number two cylinder was removed and examined, and no anomalies were noted with the internal engine components.