On January 9, 1995, at 1805 central standard time, a Cessna 182P, N7340Q, was substantially damaged during landing near Lufkin, Texas. The private pilot received minor injuries. Visual meteorological conditions prevailed for the planned night cross country flight. On the enclosed statements, witnesses reported the information in this paragraph. The airplane was observed flying over the airport and performing figure eights at the approach end of runway 15 before flying to runway 25. Subsequently, the airplane was observed maneuvering in "several tight circles" before making an approach to runway 25. One witness stated that during the approach, the airplane "was crossing the runway threshold at about 20 feet...flew level down the center of the runway with plenty of power and good airspeed." About 1/3 of the way down the runway, the airplane "dropped it's left wing, spun, and hit the ground." One witness stated that the "aircraft made an abrupt left dive and hit the ground." A Texas Department of Public Safety (DPS) Trooper (statement enclosed) reported the pilot saying that he was taking several types of medication including Diazapan, Vicodine, Tylenol 3, and Phianol. Blood samples were collected and forwarded to the DPS Laboratory. Another DPS trooper (statement enclosed) reported that he landed his airplane at about 1800 and observed the airplane approaching from the south with the landing light on. During telephone interviews, conducted by the Federal Aviation Administration (FAA) inspector, the pilot reported that the flight departed Cleburne, Texas, with an original planned destination of McAllen, Texas; however, en route he felt that the navigation equipment was not functioning properly. Subsequently, the flight landed at Horseshoe Bay Airport, Marble Falls, Texas, where the airplane was refueled and the pilot decided to return to Cleburne, Texas. He further stated that he got lost due to the navigation equipment, experienced a total electrical failure and the flight ended at Lufkin, Texas (150 miles southeast of Cleburne, Texas). He reported that airplane interior lights and the landing light would not work, and that he had put down the flashlight just prior to the landing. When questioned by the inspector, the pilot confirmed that he was taking medications; however, he stated that he had not taken any of the drugs during the flight. The airplane came to rest on a measured magnetic heading of 165 degrees 65 feet to the south of runway 25. An examination by the FAA inspector and manufacturer representatives did not disclose any airframe, engine, or equipment anomalies. The attitude indicator read 30 degrees down pitch and 30 degrees left bank. The electromechanically operated flaps were found in the fully extended position. Cockpit light switches were in the "ON" position. One navigation instrument was set on the Corpus Christi VORTAC (115.5 MHz) and one on the San Antonio Vortac (116.8 MHz). Both of these locations are beyond 150 miles south of the planned route. The Texas Department of Public Safety Laboratory toxicology (report enclosed) was positive for Diazepam (0.20 milligrams per liter), Nordiazepam (0.55 milligrams per liter), and Butalbital (6.9 milligrams per liter). According to Dr. Dennis V. Canfield, of the Federal Aviation Administration Civil Aeromedical Institute, these "levels are significant to cause impairment." Numerous attempts were made by the investigator-in-charge to obtain the Pilot/Operator Report (NTSB Form 6120.1/2). The report has not been received. The airplane was release to the owner's representative.