On September 8, 1995, at 1810 eastern daylight time (edt), a Cessna 188, N5623J, piloted by a commercial pilot, was destroyed by fire after colliding with trees and terrain during its initial climb after takeoff. The 14 CFR Part 137 flight was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot was fatally injured. The flight departed Greenville, Michigan, at 1810 edt. According to the Kent County Sheriff's Department report, witnesses said N5623J's engine was "...cutting in and out... not running well... [and] not operating properly... ." These witnesses said they saw the airplane skimming the tree tops as it went past their vantage point. One witness resides on the airport boundary. She said the airplane appeared to have a later liftoff than those she has seen in the past. Federal Aviation Administration Principal Maintenance and Operations Inspectors (PMI and POI respectively) conducted the on-scene investigation. The PMI said the fuselage center section had been involved in an intense fire. The right wing was pointed about 80 degrees above the horizon and had been fire damaged. The left wing had separated from the fuselage and was lying next to the fuselage tail cone. The POI said a chemical spill was found about 130 feet north of runway 18's departure end and continued to the accident site. Based upon his observation, N5623J began striking tree tops about 500 feet from the runway's departure end. N5623J continued for about 1,200 feet on a heading of 155 degrees magnetic, striking trees. After flying this distance N5623J's flight path made a turn to an easterly heading, descending into the trees and eventually onto the ground. A detailed drawing of N5623J's flight path is appended to this report. The PMI reported control continuity for all three flight controls. He said the propeller blades were curled about 12 inches in from the tips. He said the leading edges of the propeller blades were nicked over their entire span. The chemical dump chute was found in the open position. The PMI reported the engine inspection revealed compression in all six cylinders. The magnetos produced spark when hand rotated. The engine driven fuel pump had a sheared drive shaft. The NTSB Metallurgical Laboratory in Washington, D.C. examined the fuel pumps drive shaft. The metallurgist's report stated the sheared drive shaft displayed no evidence of pre- existing fracture areas. A microscopic examination of the shaft showed the separation was "...typical of a ductile shear overstress separation from torsional loading." The pump could not be rotated by hand pressure. The report notes: "...there were no separations or obvious chips of material blocking [the] rotation of the pump." A sticky residue was noted within the pump cavity and on the cover plate. The Kent County, Michigan, Medical examiners' autopsy report states the pilot's fatal injuries were the result of multiple injuries caused by the accident. The autopsy report states, "Myocardis predominantly involving the posterior wall of the [heart's] left ventricle." The report also showed the pilot had arteriolonephrosclerosis, a hardening of the arteries in the kidney. The pathologist stated, "The myocardis may have caused an arhythmia which might have caused the deceased to lose consciousness and thus lose control of the aircraft." The FAA's Civil Medical Institute conducted the pilot's toxicological examination. The results of the examination revealed an unspecified amount of norpropoxyphene in the urine sample provided by the pathologist. Norpropoxyphene, according to the 1993 edition of the Physician's Desk Reference (PDR), is a derivative of propoxyphene. Propoxyphene is a "...centrally acting narcotic analgesic agent." Norpropoxyphene "...has substantially less central nervous system depressant effect than propoxyphene but a greater local anesthetic effect...," according to the PDR.