HISTORY OF FLIGHTOn September 24, 2020, about 1105 central daylight time, a Quicksilver MX II airplane, N9045Z, was substantially damaged when it was involved in an accident near Killeen, Texas. The pilot and the pilot-rated passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane departed from Skylark Field Airport (ILE), when shortly after takeoff the airplane’s engine stopped producing power. Witnesses reported seeing the airplane maneuver and descend without engine power. The airplane impacted the median of a divided highway and then struck a guard rail. A dash-cam video was provided by a motorist that was traveling eastbound on Highway 14 near ILE. The highway was about 0.3 miles south of the approach end of runway 1 at ILE. The airplane could be seen in the frame traveling toward the north. The airplane was at a low altitude and its wings were rocking side-to-side as it traveled north. As the airplane crossed the eastbound lanes of the highway, the right wing dropped, and the airplane descended into the median between the eastbound and westbound lanes. PERSONNEL INFORMATIONThe pilot had applied for BasicMed. According to Federal Aviation Administration (FAA) records, he submitted the Comprehensive Medical Examination Checklist (CMEC) on June 15, 2017, and had most recently completed the BasicMed course on July 16, 2019. AIRCRAFT INFORMATIONThe airplane was constructed with an aluminum tube structure and open-air seating for two occupants in a side-by-side arrangement. The airplane was manufactured in 2000. The pilot/owner applied for and received a Special Airworthiness Certificate for the airplane on September 22, 2007. An entry in the maintenance records indicated that another Special Airworthiness Certificate was issued on September 9, 2020. Maintenance records for the airplane showed that on September 22, 2008, the airplane was damaged in a forced landing with the maintenance entry noting: “(Aircraft) damaged forced landing will (require) inspection, disassembly of complete (aircraft). Major repair airframe, verify inspections and airworthiness requirements.” Subsequent entries indicated that the airplane was repaired, including an overhaul of the engine on May 25, 2010. According to the records, the airplane was repaired but not flown until September 12, 2020. The entry on that date indicated that 8 takeoffs and landings were completed. The final entry was dated September 19, 2020. No entries regarding engine overhaul were found after the May 25, 2010, overhaul entry. The manufacturer recommended overhaul interval was 5 years or 300 hours of operation, whichever occurred first. According to the kit manufacturer’s published specification for the airplane, it had a typical useful load of 390 pounds. The combined weights of the pilot and passenger based on their most recent medical examinations was 414 pounds. This did not account for the weight of the fuel that was on board the airplane. AIRPORT INFORMATIONThe airplane was constructed with an aluminum tube structure and open-air seating for two occupants in a side-by-side arrangement. The airplane was manufactured in 2000. The pilot/owner applied for and received a Special Airworthiness Certificate for the airplane on September 22, 2007. An entry in the maintenance records indicated that another Special Airworthiness Certificate was issued on September 9, 2020. Maintenance records for the airplane showed that on September 22, 2008, the airplane was damaged in a forced landing with the maintenance entry noting: “(Aircraft) damaged forced landing will (require) inspection, disassembly of complete (aircraft). Major repair airframe, verify inspections and airworthiness requirements.” Subsequent entries indicated that the airplane was repaired, including an overhaul of the engine on May 25, 2010. According to the records, the airplane was repaired but not flown until September 12, 2020. The entry on that date indicated that 8 takeoffs and landings were completed. The final entry was dated September 19, 2020. No entries regarding engine overhaul were found after the May 25, 2010, overhaul entry. The manufacturer recommended overhaul interval was 5 years or 300 hours of operation, whichever occurred first. According to the kit manufacturer’s published specification for the airplane, it had a typical useful load of 390 pounds. The combined weights of the pilot and passenger based on their most recent medical examinations was 414 pounds. This did not account for the weight of the fuel that was on board the airplane. WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest inverted next to the westbound guard rail. The right wing was intact and the left wing had multiple breaks from impact. The fuselage structure was deformed. A postrecovery airframe examination did not reveal any pre-impact anomalies. An engine examination revealed that the magneto side piston had evidence of piston scoring consistent with “cold seizure.” Cold seizure results from a thermal imbalance of pistons and cylinders due to improper warm-up of the engine and excessive temperature differences between the coolant exiting the engine compared to coolant entering the engine. The accident airplane was equipped with a larger cooling radiator than the radiator supplied by the engine manufacturer. Manufacturer documentation indicated that the maximum temperature difference of the coolant between the radiator entrance and exit should not exceed 43° F. MEDICAL AND PATHOLOGICAL INFORMATIONThe FAA Forensic Sciences Laboratory identified hydrocodone and its metabolites (dihydrocodeine and hydromorphone), chlorphenaramine, dextromethorphan and its metabolite (dextrorphan), acetaminophen, salicylic acid, and albuterol in specimens obtained from the pilot. Hydrocodone is a prescription opioid medication that typically carries a warning that it may impair mental or physical abilities needed to perform potentially hazardous activities such as driving a car or operating machinery. Chlorpheniramine is a sedating antihistamine medication that is available over the counter in a variety of cold and allergy products and is also sometimes used as a sleep aid. It typically carries a warning that it may cause drowsiness, and that user should exercise caution when driving a motor vehicle or operating machinery. Dextromethorphan is a cough suppressant medication that is available over the counter in a variety of cold and allergy products. At medicinal doses, dextromethorphan alone is generally not impairing. Acetaminophen is a pain- and fever-reducing medication that is commonly available over the counter, either alone or as an ingredient in a variety of cold, allergy, and other products. Salicylic acid is a metabolite of aspirin, an over-the-counter medication commonly used to treat pain and fever, and (when taken regularly) to reduce cardiovascular risk. Albuterol is a prescription medication commonly used to relax tight lungs and improve wheezing and cough in a variety of conditions such as asthma and bronchitis. Acetaminophen, salicylic acid, and albuterol are generally not considered impairing.