Narrative:

I was making takeoff and lndgs at an uncontrolled airport. The airplane I was following stopped on the runway so I had to do a go around. At that time, the airplane on the runway started its takeoff roll so I departed my climb out slow and shallow with the gear down to remain in the traffic pattern and to keep a visual on the much slower traffic. Concentrating on maintaining separation, I don't remember retracting the landing gear, I thought it was down. Also, the gear warning horn didn't activate and I landed gear up.

Google
 

Original NASA ASRS Text

Title: PLT OF SMA EXECUTES GAR DUE ACFT STOPPED ON RWY. MONITORING OTHER ACFT AS HE CLBS OUT AND ENTERS PATTERN, LANDS GEAR UP.

Narrative: I WAS MAKING TKOF AND LNDGS AT AN UNCTLED ARPT. THE AIRPLANE I WAS FOLLOWING STOPPED ON THE RWY SO I HAD TO DO A GAR. AT THAT TIME, THE AIRPLANE ON THE RWY STARTED ITS TKOF ROLL SO I DEPARTED MY CLBOUT SLOW AND SHALLOW WITH THE GEAR DOWN TO REMAIN IN THE TFC PATTERN AND TO KEEP A VISUAL ON THE MUCH SLOWER TFC. CONCENTRATING ON MAINTAINING SEPARATION, I DON'T REMEMBER RETRACTING THE LNDG GEAR, I THOUGHT IT WAS DOWN. ALSO, THE GEAR WARNING HORN DIDN'T ACTIVATE AND I LANDED GEAR UP.

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.