HISTORY OF FLIGHT On January 22, 1994, approximately 1905 hours central standard time, a Piper PA-28-181, N4510N, operated as a rental aircraft by NorthStar Aviation, Inc., of Mankato, Minnesota, impacted terrain in an open field in the vicinity of Waseca, Minnesota. The airplane was destroyed. The noninstrument rated private pilot and three passengers received fatal injuries. Instrument meteorological conditions prevailed at the time of the accident, no flight plan was filed. The flight operated under 14 CFR Part 91, and originated from Rochester, Minnesota approximately 1810 hours. The pilot and his brother departed the Mankato Municipal Airport (MKT) about 1700. They told family members they intended to fly to Rochester Municipal Airport (RST) to pick up two passengers for a pleasure flight. Upon their arrival in the Rochester area, the pilot had difficulty establishing two-way communications with RST Air Traffic Control (ATC). ATC controller statements indicate the pilot's transmissions were loud and clear, but he did not respond to transmissions from Approach or Local Controllers. The controllers stated the pilot followed lost communications procedures, and landed without incident. During a subsequent telephone conversation, the pilot told controllers he had radio problems, and requested instructions for a no radio (NORDO) departure. The Controller statements indicate approximately 1810 the airplane taxied to the departure end of Runway 13, and received a green light gun signal clearance to takeoff. The Local Controller stated the airplane took off, made a left downwind departure from the traffic pattern, and proceeded west-northwest bound. Radar data revealed the airplane maneuvered at altitudes between 2,000 feet and 5,300 feet before it descended below radar coverage at 2,200 feet. The last radar target was approximately 2 miles west of the accident site about 1846 hours. Radar data depiction charts are appended. Waseca residents reported they heard the airplane fly overhead about 1900. They stated they could not see the airplane due to the dense fog which had suddenly developed (see WEATHER.) It is estimated the airplane impacted terrain in an open field about 1905. The wreckage was discovered by the property owner approximately 0715 the next morning. Statements from local residents are appended. CREW INFORMATION The pilot held a Private Pilot Certificate, Number 477028143, with airplane single engine land privileges, issued November 22, 1992. The pilot's flight logbook indicated 117.4 hours total flight time, including 23.2 hours in the accident make and model airplane, and 12.9 hours at night. The most recent logged night flight occurred on December 8, 1993. The pilot had logged 1.7 hours of simulated instrument flight time, with no actual instrument flight time. The most recent logged simulated instrument flight took place on July 28, 1993. The pilot held a Third Class Medical Certificate with no limitations, issued on March 5, 1993. METEOROLOGICAL INFORMATION The pilot obtained a complete weather briefing through the Minnesota Weather Advisory Service (Mn/WAS) approximately 1600 (all times local) before his departure from Mankato, Minnesota. The area weather forecast for the southern part of the state predicted scattered (occasional scattered to broken) clouds at 12,000 feet, with cirrus clouds above, and an extended outlook for VFR conditions. The terminal forecasts for Minneapolis, Minnesota (MSP, 50 NM north-northeast of the accident site) and Rochester, Minnesota (RST, 45 NM east-southeast of the accident site) predicted scattered clouds at 25,000 feet, with occasional 5 miles visibility in fog. These forecasts were originally valid from 1000 on January 22, 1994 to 1000 on January 23, 1994. Amended terminal forecasts were issued as weather conditions changed throughout the evening. The MSP terminal forecast was amended at 2001, to predict IFR conditions due to ceilings and visibilities, until 0800 the next morning. The RST terminal forecast was amended at 1901 and 2001. Both amended RST terminal forecasts predicted IFR conditions through at least 0800 the next morning. The first RST amendment indicated 600 foot ceilings and 3 miles visibility, with occasional skies partially obscured, 200 foot ceilings and 3/4 mile visibility in fog until midnight. The second RST amendment predicted conditions as low as sky obscured with a 100 foot ceiling and 1/8 mile visibility, until 0800 the following morning. The Surface Analysis weather observations for MKT, Owatonna (OWA, about 10 NM east of the accident site), and RST when the pilot departed Mankato indicated clear skies and unrestricted visibility. When the pilot departed RST at 1810, that facility was still reporting clear skies with 12 miles visibility, while MKT and OWA reported a scattered to broken cloud layer at 900 feet above the ground, and decreasing visibilities. At 1855, MKT reported skies partially obscured, a scattered layer of clouds at 100 feet, and two miles visibility. Copies of pertinent weather reports are appended. Several local residents reported they were surprised when it suddenly became foggy between 1830 and 1900 the night of the accident. One couple was cross country skiing near their home between 1730 and 1900. The wife stated they expected it to be clear, with "good moonlight" to ski by, but about 1830 to 1845 they noticed the developing fog reduced their visibility. She stated: "Just before returning home...I noticed how thick the fog had become in such a short period of time." She reported they arrived home about 1900 and as they removed their skis, they heard a small airplane flying overhead. She stated: "We both commented how unusual it was to hear a small plane at that hour on a Saturday night, also considering the poor visibility due to the fog." Another local resident reported she had "...made a quick trip into town after supper...was surprised at how very foggy it had suddenly become." She stated: "Sometime that evening (...6 - 8 PM) I heard a plane flying relatively low overhead. It registered in my mind because my reaction was...He must be flying by instruments...It's a good thing he knows what he's doing...because it was so very foggy out that I sure wouldn't have wanted to be up in the air at that time." Statements from the local residents are appended. COMMUNICATIONS ATC records indicate the pilot experienced difficulty establishing two-way radio communications with RST Air Traffic Control Tower (ATCT) at Rochester, Minnesota. The pilot first attempted to contact RST Approach Control about 1720. The Approach Controller (AC) stated: "I responded to his call, to no avail." Minutes later, the pilot attempted to contact RST Local Control. When the local controller (LC) responded to his call, "...N4510N did not respond to my transmissions. The aircraft continued inbound and executed lost communication procedures... ." The LC reported he signalled the pilot he was "cleared to land" and "cleared to taxi" using appropriate light gun signals. The airplane landed and taxied to the fixed base operator (FBO) without further incident. After the airplane was parked the AC contacted the FBO by telephone "...to ascertain the call sign of the NORDO aircraft." He stated he spoke with the pilot, who advised he had radio problems inbound to Rochester, and inquired about no radio departure procedures. The AC described the procedure and requested a telephone notification before the pilot departed. Approximately 1800, the pilot telephoned the Rochester ATCT, indicating he intended to depart in 10 minutes and requesting instructions. The local controller stated: "I told him to taxi out to Runway 13, complete his runup, then turn towards the control tower and flash his landing light when he was ready to depart." About 10 minutes later, the controller observed an airplane taxi from the FBO to Runway 13, pause for a few moments, then flash the landing light at the tower. The LC signalled "cleared for takeoff" with a steady green light gun signal, and the airplane departed. The controller stated the pilot made a left downwind departure and proceeded west-northwest bound with the transponder set on 1200. There is no record of further communication with the pilot of the accident airplane. FAA Air Traffic Controller statements are appended. WRECKAGE/IMPACT INFORMATION The airplane impacted terrain in a plowed, snow-covered field approximately 1 1/4 miles northwest of the Waseca Municipal Airport, in Waseca, Minnesota. The path from initial impact to the main airplane wreckage was about 117 feet long, and oriented on an approximate 100 degree heading. The wreckage was removed from the field and relocated to a hangar at the Waseca Municipal Airport. Postaccident examination revealed no evidence of preimpact mechanical anomaly of airframe, engine or systems. MEDICAL/PATHOLOGICAL INFORMATION Autopsy examination of the pilot revealed no evidence of preexisting disease. The autopsy (report #A 94-08) was conducted on January 24, 1994, by Drs. Dennis D. Gremel and Gordon H. Herbst at Immanuel-St. Joseph's Hospital, 1025 Marsh Street, P.O. Box 8673, Mankato, Minnesota, 56002. Toxicological examination of the pilot detected Cannabinoid (11- nor-delta-9-tetrahydrocannabinol-9-carboxylic acid) in the urine. FAA Medical personnel stated the Cannabinoid is "...an inactive metaballoid of marijuana, below quantitative cutoff...the only thing it tells us is (the pilot) had smoked marijuana at some time in his life." ADDITIONAL INFORMATION The airplane wreckage was released to the owner's representative upon completion of the onscene investigation, on January 24, 1994.