CEN20LA258

The pilot reported the engine seemed to lose power shortly after takeoff. His attempts to restore engine power were not successful, and he executed a forced landing. A postaccident engine examination revealed evidence of an insect (mud dauber) nest within the carburetor heat induction system. The pilot purchased the airplane 2 days before the accident. Airplane maintenance records indicated that an annual inspection was completed on the day the airplane was sold to the accident pilot. The records also indicated the airplane had not been flown between the annual inspection in 2017 and the most recent inspection 2 days before the accident. Furthermore, the markings on the oil filter suggested that the oil was not changed during the most recent annual inspection. The airplane was operated 1.16 hours since that most recent inspection. The insect nest in the carburetor heat system likely became dislodged during airplane operation and subsequently restricted air flow to the carburetor resulting in a loss of engine power. The location of the insect nest was not in an area visible to the pilot during a preflight inspection. However, the presence of the nest could have been detected during a thorough and complete annual maintenance inspection. In addition, the failure of the mechanic to change the engine oil and filter during the most recent annual inspection suggested that the inspection was less than thorough and complete. Although there was a slight possibility of carburetor icing at glide and cruise power, it is unlikely to have been the cause of the power loss since the loss of engine power occurred shortly after takeoff.

On July 1, 2020, about 1932 central daylight time, a Piper PA-28-140 airplane, N6530W, was involved in an accident near Bridgeport, Texas. The pilot and two passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported the before takeoff engine run-up was normal. After takeoff, about 150 ft. above ground level, the engine seemed to lose power without any associated vibration, abnormal noise, or indications. The pilot’s attempts to determine the cause of the problem and restore engine power were not successful. He executed a forced landing “to a field of medium-maturity mesquite trees.” A post-recovery engine examination revealed evidence consistent with an insect (mud dauber) nest within the carburetor heat induction system. Specifically, the inside surface of the carburetor heat shroud exhibited residue consistent with dirt/mud accretion. The engine exhaust tube common to the carburetor heat shroud exhibited a discoloration consistent with debris accretion. The discolored area on the exhaust tube coincided with the residue observed on the inside of the carburetor heat shroud. A fragment of compacted dirt was recovered from inside the carburetor heat duct, and the outboard end of the muffler exhibited a similar dirt/mud residue. No other anomalies were observed with respect to the engine installation. According to the airplane maintenance records, an annual inspection was completed on September 14, 2017, at a recording tachometer of 2,701.58 hours. The next annual inspection based on the maintenance records was completed on June 29, 2020. The tachometer time corresponding to that inspection was 2,701.68 hours. The pilot reported that he purchased the airplane the same day as the most recent annual inspection. The accident occurred 2 days later, on July 1. The tachometer indicated 2,702.84 hours at the time of the postaccident examination. The oil filter installed on the engine at the time of the postaccident examination was dated September 15, 2017. The tachometer time noted on the filter was 2,701.58 hours. The most recent inspection logbook entry did not include any reference to changing the engine oil and filter. However, the logbook entry corresponding to the prior inspection in 2017, which was conducted by the same mechanic, specifically noted that the engine oil and filter were replaced, and the old filter was opened and inspected for debris. According to a graph in FAA Special Airworthiness Information Bulletin CE-09-35, Carburetor Icing Prevention, the weather conditions at the time of the accident corresponded to a slight possibility of carburetor icing at glide or cruise power.