Narrative:

Aircraft #1 was inbound on the right 45 degree traffic pattern entry, about 3 NM out. I saw a C150, aircraft #2, to my left and 100 ft lower. I stopped my descent into the airport traffic pattern and started an immediate climbing right turn. The other pilot took no actions.

Google
 

Original NASA ASRS Text

Title: SINGLE ENG CESSNA PLT TAKES EVASIVE ACTION WHEN ENTERING TFC PATTERN TO AVOID COLLISION WITH ANOTHER SINGLE ENG CESSNA ENTERING TFC PATTERN BENEATH HIM.

Narrative: ACFT #1 WAS INBOUND ON THE R 45 DEG TFC PATTERN ENTRY, ABOUT 3 NM OUT. I SAW A C150, ACFT #2, TO MY L AND 100 FT LOWER. I STOPPED MY DSCNT INTO THE ARPT TFC PATTERN AND STARTED AN IMMEDIATE CLBING R TURN. THE OTHER PLT TOOK NO ACTIONS.

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.