A friend of the private pilot accompanied him on the flight leg before the accident flight; she stated that, while approaching to land, the weather became "very turbulent" and that, after they landed, it was "very windy and raining very hard." The pilot stated that he needed to continue his flight in order to attend a family event, and the passenger suggested that he wait for the weather to improve. During this time, the pilot requested fuel for his airplane from line personnel at the airport's fixed base operator (FBO), who asked if the pilot could wait to receive fuel due to the adverse weather. The pilot stated that he needed fuel "now" and requested that the line personnel wipe his fuel caps with a towel and use an umbrella to prevent rainwater from entering the fuel tanks. After waiting about 45 minutes for the weather to improve, the pilot stated to FBO personnel that he was "heading out"; when asked if he had found a break in the weather, the pilot said he was "gonna go for it." Based on the pilot's comments to his passenger and FBO personnel, he was likely experiencing self-induced pressure to complete the flight despite the poor weather conditions in order to attend the family event.The pilot subsequently departed on the 65-mile instrument flight rules (IFR) flight. While en route, the controller told the pilot that the airplane's target was "all over the place" and asked if he needed assistance. The pilot indicated that this was due to the wind conditions and declined to change cruise altitudes. The controller then cleared the pilot for the instrument approach at the destination; while the pilot was conducting the approach, the radar controller advised the local controller that the airplane was "going back and forth" through the approach course. Shortly thereafter, the pilot executed a missed approach and asked to try the approach again. The controller provided headings and altitudes to the pilot, then asked if he would like to try an approach at a nearby airport that was reporting better weather conditions. The pilot accepted and the controller provided a heading and altitude toward that airport. The pilot acknowledged the heading but did not acknowledge the altitude assignment; there were no further communications from the pilot and radar contact was lost shortly thereafter.Review of weather radar information showed light to moderate intensity echoes over the route of flight and the accident site consistent with rain showers, and soundings depicted a high probability of moderate or greater low-level turbulence in the area. Conditions about the time of the accident at a Page 2 of 11 ERA18FA030nearby airport included 1-1/4 mile visibility in heavy rain and a broken cloud ceiling at 100 ft above ground level. Although the pilot contacted flight service to file his IFR flight plan, he did not request a weather briefing at that time, and what, if any, weather information he obtained before the flight could not be determined.Examination of the airplane, engine, and propeller components did not reveal any anomalies that would have precluded normal operation. Review of the pilot's logbook revealed that he did not meet recency requirements to act as pilot-in-command in instrument meteorological conditions (IMC). In addition, his communications with air traffic control and the airplane's flight path during the approach is consistent with a lack of proficiency while operating in IMC. The reduced visibility conditions present at the time of the accident were conducive to the development of spatial disorientation, and the damage to the airplane indicated a high-energy impact consistent with the known effects of spatial disorientation. It is likely that the pilot experienced spatial disorientation while maneuvering after a missed approach, which resulted in a loss of control.