The airline transport pilot and four passengers planned to make a 300-nautical-mile cross-country flight in the airplane to return home. They arrived at the airport about noon and loaded their bags into the airplane. The pilot made an unsuccessful attempt to start the engines, and the occupants deplaned and waited for some time. During a second attempt to begin the flight, a ground controller informed the pilot that he was required to file an instrument flight rules (IFR) flight plan before departure. After the occupants deplaned a second time, they went to the airport terminal where the pilot asked a flight school employee to provide instructions for filing an IFR flight plan. According to the flight school employee, the pilot appeared rushed, and the passengers were anxious to complete the flight. According to the surviving passenger, after one of the other passengers started to make ground transportation arrangements, the pilot's wife insisted they would fly the passengers home. The pilot filed an IFR flight plan, and the pilot and passengers boarded the airplane for the third time. At the time of the accident, IFR conditions prevailed at the departure airport with a visibility of 2 miles in light precipitation and mist, scattered clouds at 600 ft above ground level (agl) and an overcast ceiling at 4,200 ft agl. It could not be determined when the pilot had last flown in instrument meteorological conditions or when he had last completed an instrument competency check. However, it is likely that the pilot was not instrument current as he was unfamiliar with basic instrument flight planning procedures and had to be coached through the readback of his IFR clearance.The airplane departed normally and entered a climb. Seconds later, the airplane entered a cloud and began a turn, at which time it began to shake violently as the stall warning horn sounded, consistent with an aerodynamic stall. The airplane descended from about 900 ft above ground level and impacted multiple residences about 1 nautical mile from the departure airport. Examination of the airframe and engines revealed no evidence of any preimpact mechanical malfunctions that would have precluded normal operation. The blades of both propellers displayed rotational damage signatures that were consistent with the engines producing power at impact.Page 2 of 12 WPR17FA066Toxicology results indicated that the pilot was not impaired by carbon monoxide or drugs. Although the pilot's autopsy showed that he had coronary artery disease and was at increased risk of incapacitation from a cardiac event, the surviving passenger reported that the pilot was manipulating the controls during the descent to impact. Therefore, pilot impairment or incapacitation likely did not contribute to the accident. The pilot's decision to complete the flight despite the IFR weather conditions was likely driven by his own self-induced pressure, influenced by the passengers' need to return home and his wife's insistence that the departure would proceed as originally planned.    Calculations indicated that the airplane was loaded over its maximum gross takeoff weight by about 300 pounds. Additionally, the airplane's center of gravity (CG) was forward of the forward limit for its maximum gross weight. Although CGs that are forward but within the approved envelope generally result in more favorable stall characteristics, the airplane was loaded outside of published limits, and its performance under these conditions was unpredictable.