The pilot and passenger departed during the middle of the day for a nearly 7-hour instrument flight rules cross-country flight with one fuel stop. During the fuel stop, the pilot reported to an airport employee that he was trying to time his flight to arrive at the destination between two thunderstorms. The flight departed and entered the destination airport area at night without incident. Air traffic control cleared the pilot for a straight-in instrument landing system approach and advised him that the cloud ceiling was 200 ft above ground level, which was the decision height for the straight-in instrument landing system approach the pilot was about to perform.The pilot told the controller that the airplane was established on the final approach course. However, between the initial approach fix and final approach segment the airplane’s altitude and flightpath showed deviations, and the pilot was cautioned of those deviations by controller. Additionally, the airplane crossed the initial approach fix about 500 ft below the specified crossing altitude and about 700 ft below the expected altitude at the final approach fix. As the airplane continued in the final approach segment, continuous deviations to the left and right of course occurred. The airplane subsequently descended below the decision height for the approach and impacted heavily wooded terrain about 1.55 nautical miles from the runway threshold in a 18°-to-20° descent. The wreckage was highly fragmented, but all major components of the airplane were located in the debris path. No evidence indicated any preimpact mechanical malfunction or failure of the airplane. The evidence also indicated that the engine was producing power at the time of impact. Page 2 of 13 ERA22FA149Prior to the accident, the airplane had ongoing autopilot altitude-hold control issues despite several recent maintenance corrective actions. The pilot was aware that the autopilot issue persisted, and he told a friend a few days before the accident flight that he felt comfortable hand flying the airplane during the long cross-country flight. The investigation was unable to determine whether the autopilot was activated during the approach, and testing of the autopilot system could not be performed due to the significant impact damage to the airplane and autopilot components. Furthermore, a safety pilot who had flown with the accident pilot reported that it was typical of the pilot to turn off the autopilot for instrument approaches and hand fly the airplane. Thus, it is likely that the pilot flew the accident approach without the autopilot engaged.The weather observed at the destination airport had deteriorated significantly after the pilot departed for the last leg of the flight, and the weather was worse than the expected forecast conditions. During the approach, the controller advised the pilot of the low ceiling and visibility and advised that other nearby airports were reporting better weather conditions. The pilot responded that he would continue the approach. Review of the weather at the alternate airport for the flight, which was about 25 to 30 minutes away from the planned destination, found that visual flight rules conditions were occurring during the time surrounding the accident. It is likely that had the pilot discontinued the instrument approach and diverted to the alternate airport after the approach had become unstable, and after having been warned of his flightpath deviations, the accident would have been avoided.Review of the pilot’s logbook found that he had logged less than 2 hours of night experience during the 12 months preceding the accident and had logged no night flights in the 90 days before the accident. The pilot had logged 11 instrument approaches in the 6 months that preceded the accident. The pilot’s total actual instrument experience was 32 hours, but only 2.5 hours of this time was logged as night actual instrument experience. In addition, the pilot was disapproved twice when testing for his instrument airplane rating because he had become distracted and lost situational awareness and had a full-scale deflection on the glideslope during an instrument approach. Although the pilot was approved for an instrument rating on his third attempt, he likely did not possess the experience or ability to successfully complete the night instrument approach in low instrument meteorological conditions.