On April 22, 2023, about 0136 central daylight time, a Cessna 150J airplane, N60860, was substantially damaged when it was involved in an accident near Buffalo, Iowa. The pilot was not injured and the pilot-rated passenger sustained a minor injury. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
Automatic dependent surveillance – broadcast (ADS-B) data revealed that the pilot completed 3 flight legs during the evening and night. The accident occurred on the 4th flight leg. He departed Augusta Municipal Airport (3AU) about 1710 (April 21st) and arrived at Tulsa Riverside Airport (RVS) about 1818. The pilot departed RVS about 1913 and arrived at Lamar Municipal Airport (LLU) about 2037. Beginning about 2129, the pilot departed LLU and remained in the traffic pattern. The pilot reported that he completed 3 solo night takeoffs and full stop landings for currency, departed LLU about 2143, and arrived at Omar N. Bradley Airport (MBY) about 2323. The pilot then departed MBY about 0000 (April 22nd) with an intended destination of Davenport Municipal Airport (DVN). The final ADS-B data point was recorded at 0136:35, and the associated barometric altitude was 700 ft. The accident site was located about 280 yards west of the final data point.
The pilot reported that the engine lost power when the airplane was about 11 miles south-southwest of the intended destination airport. He noted a rapid drop in engine rpm as if the throttle control had been abruptly moved to idle. The engine seemed to completely lose power for about 30 to 45 seconds before it then regained power, reaching about 2300 rpm. He described it as a “strong burst” of power. About 5 to 10 seconds later, the engine lost power again. His efforts to restore engine power were not successful.
The pilot attempted to execute a forced landing to a road; however, a wind gust caused the airplane to impact a light pole and it came to rest on a set of railroad tracks. The nose landing gear collapsed and the airplane was oriented in a nose-down position with damage to the fuselage, engine mount, and both wings.
The pilot stated the airplane was fully fueled before departing 3AU and was fueled with 12 gallons (total) at LLU and with 8 gallons (total) at MBY. The passenger joined the flight at RVS, and the pilot limited the amount of fuel taken onboard to remain within the gross weight limitation for the airplane. According to the airplane owner’s manual, the maximum total and useable fuel capacity was 26.0 gallons and 22.5 gallons, respectively. According to the manual, fuel consumption varied from about 5.5 gallons per hour (gph) to about 7.0 gph.
The pilot stated the cockpit fuel gauges indicated full before the initial departure from 3AU. However, approaching MBY, they appeared to indicate near empty. At MBY, the pilot determined that each fuel tank contained about 4 gallons and he added 8 gallons. He deemed the fuel gauge indications unreliable since they did not appear to correspond to his visual fuel quantity determination and his preflight fuel calculations.
The pilot reported the engine was leaned as appropriate for all stages of flight. He also commented that, after arriving at RVS, the engine took about 2 minutes to shut down after the mixture control was moved to the idle/cutoff position. The same issue occurred upon arrival and shut down at LLU.
Postaccident examination did not identify any engine anomalies consistent with an inability to produce rated power. Both main fuel tanks appeared to be intact. The left main fuel tank appeared to contain minimal fuel along with a significant quantity of water consistent with the airplane being stored outside. The right fuel tank appeared to be empty at the time of the examinations. Both fuel caps were securely installed at the time of the initial airplane examination. However, at the time of the engine examination, the left fuel cap was not installed. The initial examination revealed the gascolator bowl contained fluid consistent in appearance to aviation fuel. The bowl was free of debris or sediment.
Weather conditions at the time of the accident were conducive to carburetor icing as noted in Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35. The bulletin noted that carburetor ice can be detected by a drop in engine speed, usually accompanied by a roughness in engine operation.