On May 20, 1999, approximately 0815 mountain daylight time, an Arctic S-1B2, N70AT, was substantially damaged when it collided with a fence during initial climb following takeoff from Lamar Municipal Airport, Lamar, Colorado. The private pilot, sole occupant aboard, was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal cross-country flight being conducted under Title 14 CFR Part 91. The flight originated minutes before the accident, with an intended destination of Rock Springs, Wyoming. According to a mechanic employed at Lamar airport, the owner of the aircraft told him that the pilot picked up the airplane in Boise City, Oklahoma, and flew to Lamar. He was also told by the owner that that was the pilot's first time flying that make and model of aircraft. During landing at Lamar, the aircraft encountered a crosswind and tipped onto its nose. The mechanic inspected the aircraft, and determined that it had sustained only minor damage. Subsequent to the inspection the following day, the pilot departed the airport en route to Rock Springs, Wyoming. During initial climb after takeoff, the pilot lost directional control after becoming airborne. The aircraft collided with a fence off the end of the runway. During the impact sequence, the right landing gear was separated from the aircraft and the leading edges of the wings and wing spar were bent. Wind conditions near the time of his departure were reported as calm. Following the accident, the pilot reported to a Federal Aviation Administration (FAA) inspector that the left tire brace strut failed. He stated that the brace swung outward, creating an asymmetrical condition. As a result, he made a forced landing in a field. However, according to the same mechanic who performed the previous inspection following the first incident, the right brace strut and landing gear had separated, not the left. It was also his opinion that the damage sustained to the right landing gear and brace strut was due to impact forces sustained during the collision with the fence. According to the Civil Aeromedical Institute's (CAMI) Aeromedical Certification Division of the FAA, the pilot has a past medical history of neuroses, including anxiety, hysteria, phobia, obsessive compulsive, and depressive disorders. In addition, he has had four drug and alcohol related offenses. According to the FAA inspector, once the pilot's medical history was discovered the day following the accident, it was too late to perform a toxicological protocol on the pilot. According to CAMI's records, the last record of the pilot being issued a valid second class airman's medical certificate was on May 13, 1991, which was issued without restrictions or limitations. On July 23, 1993, the pilot applied for a second class medical certificate, which was denied by the Aviation Medical Examiner (AME) due to an unapproved medication the pilot was taking. On July 29, 1994, August 21, 1996, and November 30, 1998, second class medical certificates were issued by an AME, but were later denied by the FAA due to the pilot's failure to provide requested information. The pilot did surrender the 1996 medical certificate, but not the other two. The NTSB attempted to contact the pilot on three separate occasions requesting the completion of NTSB Form 6120.12, the Pilot/Operator Aircraft Accident Report; on May 24, 1999, June 25, 1999, and August 25, 1999. The pilot signed for the second letter sent via certified mail on July 02, 1999. The third letter was also sent certified mail by the NTSB's Office of General Counsel, and the letter was returned as "unclaimed."