After flying one flight leg earlier in the day, the pilot flew to an intermediate stop on the way to his home base to purchase fuel. A surveillance video recording from the fueling airport showed the airplane land and taxi to the self-serve fuel pump where the engines were shut down for about 10 minutes while the airplane was fueled. The pilot then had difficulty starting both engines over several minutes. After the engines were running, the airplane taxied to the runway and did not appear to stop for an engine run-up. The pilot performed a rolling takeoff, and the airplane lifted off after a roll of about 2,100 ft, slightly more than half the available runway length. A passenger reported that after liftoff, at an altitude of about 50 to 100 ft above ground level (agl), both engines lost partial power and began “stuttering,” which continued for the remainder of the flight. He further reported that the engines did not stop, but they were “not producing full RPM.” The airplane drifted left of centerline, which a witness described as a left yawing motion. The pilot corrected the drift and flew the runway heading over the grass on the left side of the runway; however, the airplane would not climb. After crossing the end of the runway, the pilot pitched the airplane up to avoid obstacles. Automatic dependent surveillance-broadcast data indicated that the airplane climbed from about 20 to 120 ft agl in a gradual left turn. During this time the groundspeed decreased from about 80 knots to about 69 knots. The altitude then decreased to about 50 ft agl, the groundspeed decreased to about 66 knots, and the left turn decreased in radius until the recorded data ended about 100 ft west of the accident site. The airplane descended and impacted a house.  Witness descriptions of the airplane yawing to the left while over the runway and again during its final left turn suggest that the loss of engine power may not have been symmetric (that is, one engine may have suffered more of a loss than the other).   Page 2 of 11 ERA19FA249Examination of the accident site revealed that most of the fuselage forward of the aft bulkhead came to rest within the perimeter of the north side of the house and was mostly consumed by a postcrash fire. Both engines were severely damaged by impact and fire. Due to the damage, the investigation was unable to determine a reason for the loss of engine power in both engines. The surveillance video showed that the pilot did not sample fuel from the airplane sump drains after refueling, which would have provided him an opportunity to check the fuel for water or visible contaminants. However, a fuel sample taken from the airport’s fuel supply after the accident indicated no anomalies.The pilot’s difficulty starting both engines, which were likely still relatively hot (they had been shut down for about 10 minutes) combined with the ambient temperature of 30°C (86°F), suggests the possibility of fuel vapor formation in the fuel lines while the airplane was on the ramp. However, once the engine is running, the likelihood of vaporization is reduced because the fuel flow through the lines is sourced from the relatively cooler fuel supply in the fuel tanks, and airflow over the engine from the propeller also cools the fuel. Further, the use of the auxiliary fuel pumps and open cowl flaps (required by the pilot operating handbook [POH] for takeoff) also reduces the likelihood of vaporization. The investigation was unable to determine the position of the cowl flaps or the auxiliary fuel pump switches or whether fuel vaporization may have occurred during takeoff.  Additionally, the pilot did not perform the procedure indicated in the POH for takeoff in hot weather conditions, which could have provided him an opportunity to verify before takeoff that the engines were producing the required minimum RPM and the required minimum fuel flow had been established. Based on autopsy findings, the medical examiner listed atherosclerotic cardiovascular disease as a contributing cause of death. This placed the pilot at some increased risk for an acute cardiac event. However, there were no acute findings listed from the autopsy, and the surviving passenger did not describe such an event. The passenger reported the pilot was awake and alert and attempting to fly the airplane. Therefore, the pilot’s cardiovascular disease was not a contributing factor in the accident.Toxicology testing of the pilot’s blood and urine was positive for previous cocaine use. Cocaine was detected in his urine and the inactive metabolites benzoylecgonine and ecgonine methyl ester were detected in both his blood and urine. The presence of the cocaine pyrolysis product anhydroecgonine methyl ester indicates that crack cocaine was probably smoked. The absence of cocaine and anhydroecgonine methyl ester in the blood suggests that the cocaine was smoked several hours before and perhaps late effects such as fatigue or inattention may have been present, especially if the pilot was a chronic user. It is unknown how frequently the pilot used cocaine. However, given the operational and mechanical issues described by the surviving passenger and the fact that no active cocaine compound was found in the pilot’s blood, previous use of cocaine by the pilot was unlikely to have contributed to the accident.Page 3 of 11 ERA19FA249