Narrative:

Under positive control by msn approach control arriving from the west and descending out of 3;500 ft for msn airport to a left base for runway 03; we heard a traffic alert given to a cessna 310 from approach control. 'Traffic at 12 o'clock; less then a mile; descending out of 3;000 ft is a lancair.' we were then advised; 'traffic at 1 to 2 o'clock; less then a mile; climbing out of 2;500 ft is a cessna 310.' I was the pilot flying from the right seat. I immediately looked right and saw a cessna 310 staring back at be from my 2 o'clock position; climbing at me; with no relative movement in either direction; only quickly getting larger. I immediately put our lancair in a climbing left turn and watched the cessna 310 pass to our rear by 300 feet; and 100 feet below. I could hear ATC's audio alert tone going off when he gave us the advisory. We were both VFR; but under positive control in class C airspace with squawk codes. It was not busy at the time. More should have been done in this situation. I believe my evasive action prevented a serious incident. The flight resumed as normal; and a normal landing was made at msn on runway 03.

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Original NASA ASRS Text

Title: A NMAC occurred in the vicinity of MSN airport when the reporter's Lancair and a C-310; both VFR in MSN Class C airspace and in contact with Approach Control; received late traffic advisories from the Controller.

Narrative: Under positive control by MSN Approach Control arriving from the west and descending out of 3;500 FT for MSN airport to a left base for Runway 03; we heard a traffic alert given to a Cessna 310 from Approach Control. 'Traffic at 12 o'clock; less then a mile; descending out of 3;000 FT is a Lancair.' We were then advised; 'Traffic at 1 to 2 o'clock; less then a mile; climbing out of 2;500 FT is a Cessna 310.' I was the pilot flying from the right seat. I immediately looked right and saw a Cessna 310 staring back at be from my 2 o'clock position; climbing at me; with no relative movement in either direction; only quickly getting larger. I immediately put our Lancair in a climbing left turn and watched the Cessna 310 pass to our rear by 300 feet; and 100 feet below. I could hear ATC's audio alert tone going off when he gave us the advisory. We were both VFR; but under positive control in Class C airspace with Squawk codes. It was not busy at the time. More should have been done in this situation. I believe my evasive action prevented a serious incident. The flight resumed as normal; and a normal landing was made at MSN on Runway 03.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.