Narrative:

I contacted sdl tower approximately 10 mi out for a straight in approach runway 21. I was told to continue on. At this time I saw an small aircraft Y low and ahead of me, maybe 3-4 mi. Sdl tower spoke to an aircraft, perhaps this one, and asked if aircraft was east or west of final approach for runway 21. Pilot said, 'ah, I don't know, maybe west.' as I got closer, I was told to continue inbound. Approximately 3 mi out, I was asked to slow down due to an small aircraft twin the pattern, and I was told the small aircraft twin was my traffic. I did not see the traffic and told the tower this. I was told to continue inbound. At 1 1/2 - 2 mi out, an small aircraft Y flew under and in front of me, cutting off my approach. He was not talking to tower at that time. He approached from my right. My copilot spotted him first. If not for my copilot, I'm not sure when I would have seen him. At this point, I immediately initiated a left 360 degree turn and informed tower simultaneously. After I was on the ground, I called the tower on my radio and asked where that airplane came from? The controller told me that he had told me to follow that plane in. All I remember hearing was to slow down for traffic in the pattern, which was an small aircraft twin, not an small aircraft Y. My copilot does not remember being advised of the other aircraft either. I guess that I was surprised that the controller did not ask me to make a left 360 degree turn before I did. In other words, see the situation developing before I could see it, although I realize the ultimate responsibility is mine for my own safety.

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Original NASA ASRS Text

Title: SMA ON STRAIGHT IN APCH HAS NMAC WITH AN SMA.

Narrative: I CONTACTED SDL TWR APPROX 10 MI OUT FOR A STRAIGHT IN APCH RWY 21. I WAS TOLD TO CONTINUE ON. AT THIS TIME I SAW AN SMA Y LOW AND AHEAD OF ME, MAYBE 3-4 MI. SDL TWR SPOKE TO AN ACFT, PERHAPS THIS ONE, AND ASKED IF ACFT WAS E OR W OF FINAL APCH FOR RWY 21. PLT SAID, 'AH, I DON'T KNOW, MAYBE W.' AS I GOT CLOSER, I WAS TOLD TO CONTINUE INBOUND. APPROX 3 MI OUT, I WAS ASKED TO SLOW DOWN DUE TO AN SMA TWIN THE PATTERN, AND I WAS TOLD THE SMA TWIN WAS MY TFC. I DID NOT SEE THE TFC AND TOLD THE TWR THIS. I WAS TOLD TO CONTINUE INBOUND. AT 1 1/2 - 2 MI OUT, AN SMA Y FLEW UNDER AND IN FRONT OF ME, CUTTING OFF MY APCH. HE WAS NOT TALKING TO TWR AT THAT TIME. HE APCHED FROM MY R. MY COPLT SPOTTED HIM FIRST. IF NOT FOR MY COPLT, I'M NOT SURE WHEN I WOULD HAVE SEEN HIM. AT THIS POINT, I IMMEDIATELY INITIATED A L 360 DEG TURN AND INFORMED TWR SIMULTANEOUSLY. AFTER I WAS ON THE GND, I CALLED THE TWR ON MY RADIO AND ASKED WHERE THAT AIRPLANE CAME FROM? THE CTLR TOLD ME THAT HE HAD TOLD ME TO FOLLOW THAT PLANE IN. ALL I REMEMBER HEARING WAS TO SLOW DOWN FOR TFC IN THE PATTERN, WHICH WAS AN SMA TWIN, NOT AN SMA Y. MY COPLT DOES NOT REMEMBER BEING ADVISED OF THE OTHER ACFT EITHER. I GUESS THAT I WAS SURPRISED THAT THE CTLR DID NOT ASK ME TO MAKE A L 360 DEG TURN BEFORE I DID. IN OTHER WORDS, SEE THE SIT DEVELOPING BEFORE I COULD SEE IT, ALTHOUGH I REALIZE THE ULTIMATE RESPONSIBILITY IS MINE FOR MY OWN SAFETY.

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.