SMA Y NON ADHERENCE TO ATC INSTRUCTION TO FOLLOW SMA X HAD NMAC WITH SMA X. PLTDEV. SEE AND AVOID CONCEPT.

Narrative

SMA X NEARLY MISSED COLLISION WITH ANOTHER ACFT WHILE ON SHORT FINAL TO RWY 1L AT BUCHANAN FIELD IN CONCORD; CA. I WAS APPROX 1/2 MI FROM THE THRESHOLD ABOUT 200 FT AGL WHEN I WAS PASSED ON THE L BY ANOTHER HIGH WING SINGLE ENG SMA Y. THE OTHER ACFT WAS VERY CLOSE -- ABOUT 10 FT ABOVE ME AND 40 FT TO THE SIDE. I RPTED BEING PASSED TO THE TWR AND DECLARED THAT I WAS GOING AROUND. THE TWR CONFIRMED THAT I WOULD GAR AND CLRED THE OTHER SMA Y TO LAND. THE OTHER PLT CONFESSED THAT HE HAD NOT SEEN MY ACFT. I MADE A CIRCUIT IN THE PATTERN AND LANDED. THE OTHER ACFT WAS FOLLOWING ME IN THE PATTERN BUT HE APPARENTLY NEVER SAW ME. THE TWR WAS VERY BUSY AND WAS INSTRUCTING ACFT TO HOLD OUTSIDE THE ATA AT THE TIME OF THE INCIDENT. THE INCIDENT OCCURRED AT DUSK IN AN AREA SURROUNDED BY CITY LIGHTS (ALL POS LIGHTS ON MY ACFT WERE OPERATING). MY ACFT MAY HAVE BEEN MASKED BY CITY LIGHTS. THE TWR WAS CONDUCTING LNDGS AT NIGHT ON PARALLEL RWYS. THE TWR CTLRS WERE NOT PROPERLY HANDLING THE TFC FLOW. I WAS RESEQUENCED TWICE DURING MY APCH BECAUSE THE TWR DID NOT ACCURATELY KNOW THE POS OF LNDG ACFT.