AN EXPERIMENTAL SMA ON ITS FIRST FLT CAUSED AN SPI IN AN SMA TO GAR AT AN UNCTLED ARPT.

Narrative

PLT'S ACFT WAS ON INITIAL TEST FLT; REMAINING IN ARPT TFC PATTERN. THIS ACFT HAS NO ELECTRICAL SYS AND NO RADIO. TFC PATTERN HAD SEVERAL ACFT IN THE BLM TFC PATTERN. MY ACFT MERGED WITH THE EXISTING TFC AND ENTERED DOWNWIND. I NOTICED 1 RED/WHITE SMA X AHEAD OF ME AND 1 RED/WHITE SMA Y BEHIND ME IN THE TFC PATTERN. IN ORDER TO REMAIN SAFELY WITHIN THE RWY ENVIRONMENT ON THIS INITIAL TEST FLT; I SLOWED MY ACFT AND ELECTED NOT TO EXTEND MY DOWNWIND OUT AS FAR AS MANY OF THE OTHER ACFT IN THE PATTERN. SINCE MY EXPERIMENTAL ACFT HAS A HIGH SINK RATE; I WAS STILL AT 1000 FT AGL ON BASE. I MANEUVERED TO KEEP SPACING FROM THE RED/WHITE SMA X AHEAD OF ME AND DID NOT NOTICE THAT A STUDENT PLT IN ANOTHER RED/WHITE SMA Z HAD NOT SEEN ME AND TURNED BASE UNDER ME. AS I SCANNED THE ARPT TFC PATTERN; I NOTICED THAT THE RED/WHITE SMA X HAD CLRED THE ACTIVE; AND I STILL HAD A RED/WHITE SMA Y BEHIND ME. (THERE WERE 3; NOT 2 LIKE ACFT IN THE PATTERN!) TO ALLOW FOR MY HIGH SINK RATE; I STAYED HIGH ON FINAL AND; UNKNOWN TO ME; PASSED DIRECTLY OVER THE RED/WHITE SMA Z THAT CUT INTO THE SEQUENCE. THIS STUDENT PLT INITIATED A GAR; WITHOUT FURTHER INCIDENT. OBSERVERS ON THE GND WATCHING MY FLT SAW THE SMA Z INITIATE A GAR; HOWEVER; NO ONE THOUGHT THAT WE PASSED DANGEROUSLY CLOSE. THE FIGURES I USED FOR THE ESTIMATED MISS WERE PROVIDED BY THE STUDENT PLT'S ESTIMATE. TO RESTATE; I HAD FULL VIEW OF THE RWY ENVIRONMENT ON FINAL AND NEVER SAW THIS ACFT. THE SMA Z BEING A HIGH WING; LIMITED HIS UPWARD VISIBILITY AND MY MID-WING LIMITS MY DOWNWARD VISIBILITY. 1 CONTRIBUTING FACTOR COULD BE THE SIZE OF THE TFC PATTERN. MANY ACFT EXTEND DOWNWIND FOR SPACING; INSTEAD OF SIMPLY SLOWING THEIR ACFT TO A SPD THAT ALLOWS SAFE SEPARATION. NOW SEEING THE FLT CHARACTERISTICS AND VISIBILITY CHARACTERISTICS OF MY EXPERIMENTAL ACFT; I WILL MODIFY MY PROCS TO ENSURE MAX SAFE OP.