Narrative:

My aircraft was cleared to land behind a debonair and was in sight. At about 500 ft AGL I got a TCASII alert 'traffic,' centered at -200 ft. We then saw a brown/cream cessna 172/182 passing under the left wing about 50 ft horizontal and 100 ft vertical. At the TCASII RA alert we leveled or it would have been much closer. When clear we continued and landed. The cessna had been cleared for a visual behind us and apparently lost visual contact and went base to final too soon, effectively ahead of us. Fat has a lot of training on the field and other aircraft in the pattern is always part of my approach brief. I would recommend continued vigilance both on my part and the tower who, after clearing the cessna, apparently lost them, never informed me it was there and may have been distracted with a flight of 3 C130's in the pattern. Supplemental information from acn 332467: traffic situation was fairly complex, 11 aircraft on frequency. Aircraft a, a C172, was in a left closed traffic pattern for runway 29L at fat. Aircraft B, a BA32, had checked in and was cleared to land on runway 29L. 'A' was told 'you're following a jetstream on a 3 mi final.' 'a' acknowledged this transmission. I then focused my attention on an imminent situation that was developing between an FK28 on a straight-in visual approach to runway 29R and a C130 on base to runway 29R from the overhead pattern. I took immediate steps to rectify this situation and effect the necessary coordination. I then observed that 'a' had turned in front of 'B' at which time I issued instructions to 'a' to make a left 360 degree turn, and restated that he was to have followed the BA32. The pilot of 'B' later called the tower to advise he was filing an near midair collision report. I feel the cause of this situation was that 'a' acknowledged instructions that he did not fully understand. I see many instances where pilots are afraid to admit that they don't understand an ATC instruction, and I feel more emphasis should be placed on this subject in the course of pilot instruction.

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Original NASA ASRS Text

Title: TCASII ALERT ON FINAL APCH WHEN AN ACFT PASSED UNDER AND TO THE L OF RPTR. THE CESSNA HAD BEEN CLRED TO FOLLOW RPTR ACFT FOR LNDG, BUT APPARENTLY LOST THE RPTR ACFT, PASSED UNDER IT AND LANDED AHEAD OF RPTR. RPT FROM LCL CTLR INDICATES COMPLEX TFC PATTERN AND DISTRS AS A RESULT.

Narrative: MY ACFT WAS CLRED TO LAND BEHIND A DEBONAIR AND WAS IN SIGHT. AT ABOUT 500 FT AGL I GOT A TCASII ALERT 'TFC,' CTRED AT -200 FT. WE THEN SAW A BROWN/CREAM CESSNA 172/182 PASSING UNDER THE L WING ABOUT 50 FT HORIZ AND 100 FT VERT. AT THE TCASII RA ALERT WE LEVELED OR IT WOULD HAVE BEEN MUCH CLOSER. WHEN CLR WE CONTINUED AND LANDED. THE CESSNA HAD BEEN CLRED FOR A VISUAL BEHIND US AND APPARENTLY LOST VISUAL CONTACT AND WENT BASE TO FINAL TOO SOON, EFFECTIVELY AHEAD OF US. FAT HAS A LOT OF TRAINING ON THE FIELD AND OTHER ACFT IN THE PATTERN IS ALWAYS PART OF MY APCH BRIEF. I WOULD RECOMMEND CONTINUED VIGILANCE BOTH ON MY PART AND THE TWR WHO, AFTER CLRING THE CESSNA, APPARENTLY LOST THEM, NEVER INFORMED ME IT WAS THERE AND MAY HAVE BEEN DISTRACTED WITH A FLT OF 3 C130'S IN THE PATTERN. SUPPLEMENTAL INFO FROM ACN 332467: TFC SIT WAS FAIRLY COMPLEX, 11 ACFT ON FREQ. ACFT A, A C172, WAS IN A L CLOSED TFC PATTERN FOR RWY 29L AT FAT. ACFT B, A BA32, HAD CHKED IN AND WAS CLRED TO LAND ON RWY 29L. 'A' WAS TOLD 'YOU'RE FOLLOWING A JETSTREAM ON A 3 MI FINAL.' 'A' ACKNOWLEDGED THIS XMISSION. I THEN FOCUSED MY ATTN ON AN IMMINENT SIT THAT WAS DEVELOPING BTWN AN FK28 ON A STRAIGHT-IN VISUAL APCH TO RWY 29R AND A C130 ON BASE TO RWY 29R FROM THE OVERHEAD PATTERN. I TOOK IMMEDIATE STEPS TO RECTIFY THIS SIT AND EFFECT THE NECESSARY COORD. I THEN OBSERVED THAT 'A' HAD TURNED IN FRONT OF 'B' AT WHICH TIME I ISSUED INSTRUCTIONS TO 'A' TO MAKE A L 360 DEG TURN, AND RESTATED THAT HE WAS TO HAVE FOLLOWED THE BA32. THE PLT OF 'B' LATER CALLED THE TWR TO ADVISE HE WAS FILING AN NMAC RPT. I FEEL THE CAUSE OF THIS SIT WAS THAT 'A' ACKNOWLEDGED INSTRUCTIONS THAT HE DID NOT FULLY UNDERSTAND. I SEE MANY INSTANCES WHERE PLTS ARE AFRAID TO ADMIT THAT THEY DON'T UNDERSTAND AN ATC INSTRUCTION, AND I FEEL MORE EMPHASIS SHOULD BE PLACED ON THIS SUBJECT IN THE COURSE OF PLT INSTRUCTION.

Data retrieved from NASA's ASRS site as of July 2007 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.