Narrative:

I had called ful tower about 9 mi out and reported I had the ATIS and requested instructions to land. I was told by the tower to squawk 0300. I set my transponder to 030 and the tower told me I was clear for a straight in approach for runway 24 and I was to follow an aircraft that was southbound along the 57 freeway about at fullerton college. I reported I had the traffic and was informed by the tower that I was #2 behind that aircraft for runway 24. I continued inbound beginning to descend to pattern altitude and set up my approach speed and turned on both my landing and taxi lights. A short time later I heard an small aircraft X report he was on the south for a left downwind, runway 24 at ful. The advised the X pilot he was #3, behind an small aircraft (me) and gave my location. The X pilot acknowledged and reported he was looking for his traffic. A short time later he announced he had his traffic. The pilot then reported he was turning base. To that point I had not seen the X nor had my passenger who is a student pilot with about 55 hours. When the X pilot reported turning base I assumed he was behind me. I then heard the tower and the X discussing my location as about 1 1/2 mi final. My passenger suddenly reported an aircraft just to my left. I looked straight out my left wing and saw an X coming directly at me low. There was not time to react, the X passed directly under the wheels of my aircraft and was about 100-150' below me. There was no warning by the tower that we were on a collision course. It appeared the pilot of the X may have seen me just at the last moment, because as he started under me it appeared he began to dive and turned to the right, however he disappeared below me aircraft almost immediately. I did notice that he had navigation lights on, but did not have a landing taxi light on. I immediately called the tower and reported an aircraft had just flown beneath me. The tower called the X and ordered him to do a 360 degree turn and enter behind me for landing. It seems apparent that the X pilot saw the traffic I was following and assumed he was to follow the aircraft. It appears that he did not count or account for the # of aircraft which should put him #3. He did not have his landing lights on while in the pattern, thereby making himself more visible to other aircraft. It is also apparent that the tower should have seen when the X reported turning base that he was in danger of colliding with me. There was no warning given or instruction to alter course at all. In fact, by the conversation it would appear that the tower did detect a problem but failed to communication or control the aircraft in an effort to resolve the pending conflict.

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Original NASA ASRS Text

Title: PLT OF SMA ON FINAL FOR LNDG AT FUL AT NIGHT HAD NMAC WITH ANOTHER SMA IN TRAFFIC PATTERN.

Narrative: I HAD CALLED FUL TWR ABOUT 9 MI OUT AND RPTED I HAD THE ATIS AND REQUESTED INSTRUCTIONS TO LAND. I WAS TOLD BY THE TWR TO SQUAWK 0300. I SET MY XPONDER TO 030 AND THE TWR TOLD ME I WAS CLR FOR A STRAIGHT IN APCH FOR RWY 24 AND I WAS TO FOLLOW AN ACFT THAT WAS SBND ALONG THE 57 FREEWAY ABOUT AT FULLERTON COLLEGE. I RPTED I HAD THE TFC AND WAS INFORMED BY THE TWR THAT I WAS #2 BEHIND THAT ACFT FOR RWY 24. I CONTINUED INBND BEGINNING TO DSND TO PATTERN ALT AND SET UP MY APCH SPD AND TURNED ON BOTH MY LNDG AND TAXI LIGHTS. A SHORT TIME LATER I HEARD AN SMA X RPT HE WAS ON THE S FOR A LEFT DOWNWIND, RWY 24 AT FUL. THE ADVISED THE X PLT HE WAS #3, BEHIND AN SMA (ME) AND GAVE MY LOCATION. THE X PLT ACKNOWLEDGED AND RPTED HE WAS LOOKING FOR HIS TFC. A SHORT TIME LATER HE ANNOUNCED HE HAD HIS TFC. THE PLT THEN RPTED HE WAS TURNING BASE. TO THAT POINT I HAD NOT SEEN THE X NOR HAD MY PAX WHO IS A STUDENT PLT WITH ABOUT 55 HRS. WHEN THE X PLT RPTED TURNING BASE I ASSUMED HE WAS BEHIND ME. I THEN HEARD THE TWR AND THE X DISCUSSING MY LOCATION AS ABOUT 1 1/2 MI FINAL. MY PAX SUDDENLY RPTED AN ACFT JUST TO MY LEFT. I LOOKED STRAIGHT OUT MY LEFT WING AND SAW AN X COMING DIRECTLY AT ME LOW. THERE WAS NOT TIME TO REACT, THE X PASSED DIRECTLY UNDER THE WHEELS OF MY ACFT AND WAS ABOUT 100-150' BELOW ME. THERE WAS NO WARNING BY THE TWR THAT WE WERE ON A COLLISION COURSE. IT APPEARED THE PLT OF THE X MAY HAVE SEEN ME JUST AT THE LAST MOMENT, BECAUSE AS HE STARTED UNDER ME IT APPEARED HE BEGAN TO DIVE AND TURNED TO THE RIGHT, HOWEVER HE DISAPPEARED BELOW ME ACFT ALMOST IMMEDIATELY. I DID NOTICE THAT HE HAD NAV LIGHTS ON, BUT DID NOT HAVE A LNDG TAXI LIGHT ON. I IMMEDIATELY CALLED THE TWR AND RPTED AN ACFT HAD JUST FLOWN BENEATH ME. THE TWR CALLED THE X AND ORDERED HIM TO DO A 360 DEG TURN AND ENTER BEHIND ME FOR LNDG. IT SEEMS APPARENT THAT THE X PLT SAW THE TFC I WAS FOLLOWING AND ASSUMED HE WAS TO FOLLOW THE ACFT. IT APPEARS THAT HE DID NOT COUNT OR ACCOUNT FOR THE # OF ACFT WHICH SHOULD PUT HIM #3. HE DID NOT HAVE HIS LNDG LIGHTS ON WHILE IN THE PATTERN, THEREBY MAKING HIMSELF MORE VISIBLE TO OTHER ACFT. IT IS ALSO APPARENT THAT THE TWR SHOULD HAVE SEEN WHEN THE X RPTED TURNING BASE THAT HE WAS IN DANGER OF COLLIDING WITH ME. THERE WAS NO WARNING GIVEN OR INSTRUCTION TO ALTER COURSE AT ALL. IN FACT, BY THE CONVERSATION IT WOULD APPEAR THAT THE TWR DID DETECT A PROB BUT FAILED TO COM OR CTL THE ACFT IN AN EFFORT TO RESOLVE THE PENDING CONFLICT.

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.