Narrative:

I was departing L32 from runway 24. I was in the prescribed noise abatement pattern. I was flying a C172N (180 hp). As I turned right to head back over the airport, I announced my direction over frequency 123.0. I had completed my turn and immediately I observed a C152 passing sbound directly in front and above me. He was just passing my line of flight. I called out to the C152 on frequency 123.0, but received no response. I watched the C152 continue sbound and descending along the coast line. I lost sight of him as he neared the sdg&east power plant. I called the crq tower and inquired if they had traffic coming in from the coast from the area of the power plant. This was probably 3 or 4 mins after I lost sight of the C152. The tower reported traffic, but not a C152 (I don't know why they denied knowing of the C152). I then contacted socal approach on 127.3 and asked them if they had tracked traffic that had come down the coast. He informed me that he had not. I continued to monitor socal approach and almost immediately heard a cessna requesting flight following to el monte. I believe he had just departed crq. After obtaining approval from socal, I contacted other pilot directly. He admitted that he was the traffic I had been 'looking for.' he then related that he saw me pass under him, that he was in radar contact with the crq tower, but they did not alert him of my presence.

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Original NASA ASRS Text

Title: A C172 PLT RPTS HAVING AN NMAC WITH A C152 AS THE RPTR WAS COMPLYING WITH THE LCL NOISE ABATEMENT PROC.

Narrative: I WAS DEPARTING L32 FROM RWY 24. I WAS IN THE PRESCRIBED NOISE ABATEMENT PATTERN. I WAS FLYING A C172N (180 HP). AS I TURNED R TO HEAD BACK OVER THE ARPT, I ANNOUNCED MY DIRECTION OVER FREQ 123.0. I HAD COMPLETED MY TURN AND IMMEDIATELY I OBSERVED A C152 PASSING SBOUND DIRECTLY IN FRONT AND ABOVE ME. HE WAS JUST PASSING MY LINE OF FLT. I CALLED OUT TO THE C152 ON FREQ 123.0, BUT RECEIVED NO RESPONSE. I WATCHED THE C152 CONTINUE SBOUND AND DSNDING ALONG THE COAST LINE. I LOST SIGHT OF HIM AS HE NEARED THE SDG&E PWR PLANT. I CALLED THE CRQ TWR AND INQUIRED IF THEY HAD TFC COMING IN FROM THE COAST FROM THE AREA OF THE PWR PLANT. THIS WAS PROBABLY 3 OR 4 MINS AFTER I LOST SIGHT OF THE C152. THE TWR RPTED TFC, BUT NOT A C152 (I DON'T KNOW WHY THEY DENIED KNOWING OF THE C152). I THEN CONTACTED SOCAL APCH ON 127.3 AND ASKED THEM IF THEY HAD TRACKED TFC THAT HAD COME DOWN THE COAST. HE INFORMED ME THAT HE HAD NOT. I CONTINUED TO MONITOR SOCAL APCH AND ALMOST IMMEDIATELY HEARD A CESSNA REQUESTING FLT FOLLOWING TO EL MONTE. I BELIEVE HE HAD JUST DEPARTED CRQ. AFTER OBTAINING APPROVAL FROM SOCAL, I CONTACTED OTHER PLT DIRECTLY. HE ADMITTED THAT HE WAS THE TFC I HAD BEEN 'LOOKING FOR.' HE THEN RELATED THAT HE SAW ME PASS UNDER HIM, THAT HE WAS IN RADAR CONTACT WITH THE CRQ TWR, BUT THEY DID NOT ALERT HIM OF MY PRESENCE.

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.