History of Flight
On June 24, 2018, at about 1115 central daylight time, an Ercoupe 415-D airplane, registration N94070, impacted terrain near Monmouth Municipal Airport (C66) in Monmouth, Illinois. The private pilot and a pilot-rated passenger were fatally injured, and the airplane was destroyed. The airplane was operated by a private individual under Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight, which had departed Galesburg Municipal Airport (GBG) in Galesburg, Illinois, at 1049.
Airport surveillance video from GBG showed the airplane taxiing from the hangar area toward the end of runway 21 at 1044. After taxiing along the parallel taxiway and making a 180° turn, it departed from runway 21 at 1049. Radar data indicated the airplane traveled west after departure, made several turns, and continued west toward C66. The final radar target was recorded about 2 miles south of the accident site. A review of the GBG common traffic advisory frequency recording revealed that at 1103, the pilot announced plans to perform a touch-and-go landing at C66.
Witness Observations
A witness on a golf course about 0.3 mile south of the accident site reported seeing the airplane flying north around 1100. The witness stated that "the engine sounded like it was missing and not flying smoothly." The airplane continued north behind trees, and the witness heard the engine sound for another 15 to 30 seconds, then "heard the engine rev higher." The northbound flight path over the golf course was consistent with a left downwind leg for runway 21 at C66.
Two other witnesses, located about 0.5 mile northeast of C66, reported that the airplane was traveling east to west and flew very low over their house. They stated the engine was "sputtering and backfiring" and the airplane flew about 30 ft above them, made a steep left bank, and then impacted the ground in a wooded area. After impact, the airplane burst into flames. Both witnesses ran to the accident site but were unable to help due to the fire and extreme heat.
Wreckage and Impact Information
Postaccident examination revealed that the fuselage was consumed by fire. The empennage remained intact with minor impact and fire damage. The metal structure of both wings remained mostly intact, but the fabric covering was consumed. The two wing fuel tanks and the header fuel tank were consumed by fire; the header tank fuel quantity gauge was found with the metal rod bent near the cork end. The elevator and rudder control cables were intact and continuous. The aileron control tubes were intact from the ailerons through the wing to the fuselage, but both were fractured and bent near the fuselage.
The engine came to rest inverted and remained attached to the engine mounts and firewall. The two-blade, fixed-pitch propeller was attached to the crankshaft; one blade was bent aft near mid-span, the other straight with minimal damage. Neither blade exhibited leading edge damage or chordwise scratches. The propeller was rotated by hand, confirming engine continuity through the valve train and rear accessory section. The carburetor had separated from the engine but was sitting on the engine with fire and impact damage. The throttle cable was attached to the throttle control arm; the mixture control cable was loose from the mixture control arm and found immediately next to the carburetor.
Although fire and impact damage limited the engine examination, no preimpact mechanical malfunctions or anomalies were found that would have precluded normal operation.
Medical and Pathological Information
Autopsies were performed on the pilot and passenger by the Warren County Coroner's Office. The pilot's cause of death was attributed to thermal injuries and inhalation of products of combustion. The passenger's autopsy revealed severe coronary artery disease with 75% stenosis of the mid right coronary artery and 75% stenosis of the proximal left anterior descending coronary artery. No thromboemboli were noted, and there was no evidence of a recent or past heart attack. The cerebral and pulmonary circulations were unremarkable, and there was no obvious anatomic evidence of an incapacitating event. The passenger's cause of death was attributed to blunt force injuries.
Toxicological testing by the FAA's Forensic Sciences Laboratory detected in the pilot three previously reported medications (chlorthalidone, irbesartan, and carvedilol), none considered impairing, as well as naproxen (available in prescription and over-the-counter forms). Naproxen use was not considered a hazard to aviation safety. The passenger's toxicology detected no medications, illicit drugs, ethanol, or products of combustion that could pose hazards to flight safety.