On November 7, 1999, approximately 1130 mountain standard time, a Cessna 150E, N6158T, and a Cessna TU206F, N8758Q, both owned and operated by the pilots, collided in midair 3 miles southwest of Vance Brand Airport, Longmont, Colorado, while both were maneuvering. N6158T sustained substantial damage, and N8758Q received minor damage. There were no injuries to the private pilot and one passenger aboard N6158T, or to the commercial pilot and sole occupant aboard N8758Q. Visual meteorological conditions prevailed, and no flight plans were filed for either local flight being conducted under Title 14 CFR Part 91. The flights of N6158T and N8758Q originated at 1030 and 1000, respectively. According to the pilot of N6158T, he departed the airport for a local flight, and the sky was clear with visibility greater than 20 miles. Recorded weather observations at Broomfield, the closest weather reporting facility located 15 miles to the south, confirmed that the visibility was 60 miles with clear skies. An hour later, the pilot returned to an area southwest of the airport. He circled in the area to lose altitude and "wait for a gap" in traffic to enter a left downwind for runway 29. He stated that the traffic was "fairly heavy" and the airport's CTAF (common traffic advisory frequency) was busy with traffic reports and parachute jumping activity. He made a position report over the CTAF and stated his intention to enter the downwind for runway 29 at the midfield position. While approximately 3 miles from the airport at 6,100 feet above mean sea level (msl), he observed N8758Q to the right, "slightly above us and a little behind us, very close and closing, our flight paths converging at approximately 30 degrees." The pilot stated that he banked hard to the left, and immediately felt a "thud" as the two aircraft made contact. He then observed N8758Q to the right and slightly lower in altitude, flying to the right with no visible damage. He completed a 360 degree turn to the left, and verified that he was still able to maintain control of the aircraft and that the landing gear was still attached. He then flew a normal traffic pattern, and landed at the airport without further incident. According to the pilot of N8758Q, the traffic pattern was congested and he was aware that skydiving activity was in progress. He proceeded west of the airport and then south. He made three 360 degree turns, then headed toward the airport heading 020 degrees. He stated that while approximately 3 to 4 miles from the airport, he "felt an impact." He continued toward the airport, and landed on runway 29 without further incident. Postaccident examination of both aircraft revealed that N8758Q sustained only minor wingtip damage; however, a rib in the left wingtip of N6158T was bent. According to Title 14 CFR Part 91.113 (Right-of-way rules: Except water operations) of the Federal Aviation Regulations (FARs), subpart (b) states, "When weather conditions permit, regardless of whether an operation is conducted under instrument flight rules or visual flight rules, vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft." In addition, according to subpart (d), "When aircraft of the same category are converging at approximately the same altitude (except head-on, or nearly so), the aircraft to the other's right has the right-of-way." In the pilot of N6158T's Pilot/Operator Aircraft Accident Report (Form 6120.1/2), he was asked what recommendation he could offer as to how the accident could have been prevented. His response was, "Watch for other traffic as if they are not looking or reporting their position, especially near busy uncontrolled airports." He further stated, "Spotting the other [air]craft further away would be a much better way to avoid the situation."