SLC LCL CTLR DISTR BY AMASS (ARPT MOVEMENT AREA SAFETY SYS) ALARMS; NOT ABLE TO RESOLVE A LAND-OVER CONFLICT ON ANOTHER RWY.

Narrative

ACFT X WAS ENTERING THE L DOWNWIND OVER THE APCH END OF RWY 17 WHEN ACFT Y CALLED FOR TKOF CLRNC. I ISSUED THE DOWNWIND TFC TO ACFT Y AND CLRED HIM FOR TKOF. ACFT Y TURNED SLOWLY ON THE RWY AND BEGAN A SLOW ROLL; SO I CHKED THE PROGRESS OF ACFT X WHO WAS TURNING A 1 MI FINAL AT A HIGHER THAN NORMAL ALT. I ASKED ACFT X IF SHE WOULD BE ABLE TO LAND FROM THAT ALT. SHE RESPONDED YES; AND ASKED FOR A LONG LNDG WHICH I ACKNOWLEDGED. AT THIS TIME 'AMASS' ALARMED A GAR; RWY 35; RWY OCCUPIED. FEARING A XING SIT OR UNKNOWN ACFT FOR RWY 35 WITH MY DEP; I IMMEDIATELY SCANNED TO THE S. THE FINAL WAS A BIT HAZY AND I SAW NO ACFT OR VEHICLE ON OR NEAR RWY 35. ACFT Y THEN RPTED THAT HE HAD ABORTED TKOF. I IMMEDIATELY SENT ACFT X AROUND AND TOLD HER TO FLY TO THE E. ACFT Y AGAIN RPTED THE ABORTED TKOF. I TOLD ACFT X TO GO AROUND; AT WHICH TIME SHE RPTED ON THE GND. SHE LANDED JUST N OF TXWY K5 AND ACFT Y WAS STILL ON THE RWY JUST S OF TXWY K8. AT THE TIME AMASS ALARMED; I BELIEVED THAT ACFT Y WAS DEPARTING AND THAT I HAD SUFFICIENT TIME TO CORRECT THE SIT IF NECESSARY. I HAD 2 OTHER ACFT ON FREQ AND NO OTHER POTENTIAL CONFLICTS WITH KNOWN TFC. WHEN AMASS ALARMED FOR RWY 35; MY ATTN WAS IMMEDIATELY DIVERTED TO THE PRIORITY OF A MANDATORY GAR FOR RWY 35. I TURNED TO THE APCH END OF RWY 35 TO SCAN FOR UNKNOWN XING TFC OR ARRIVING ACFT. I DID NOT SEND ANY ACFT AROUND AS I WAS TALKING TO NO ARR ACFT ON RWY 35. IN FACT; MY FIRST CONCERN WAS THAT WHATEVER HAD CAUSED THIS EVENT ON RWY 35 WAS A POTENTIAL COLLISION WITH MY DEPARTING TFC. I DO NOT KNOW WHY ACFT Y DID NOT DEPART IN A TIMELY MANNER. IT WAS NEARLY 2 MINS AFTER HE RECEIVED TKOF CLRNC BEFORE HE RPTED ABORTING TKOF. I DO NOT KNOW WHY ACFT X LANDED OVER ACFT Y; EXCEPT THAT SHE WAS HIGH AND I ASSUME THAT SHE DID NOT SEE THE ACFT NEAR THE APCH END OF RWY 17. I DO NOT KNOW WHY AMASS ALARMED FOR RWY 35 WHEN WE WERE IN A S FLOW AND USING RWY 17. WE HAVE BEEN TAUGHT THAT THIS SYS IS SO ACCURATE THAT WE ARE REQUIRED TO ISSUE A GAR EVEN IF WE BELIEVE THAT SUFFICIENT SPACING WILL EXIST. I ALLOWED THIS CONFUSING ALARM TO DISTRACT MY ATTN FROM MY FIRST PRIORITY; ENSURING SEPARATION BTWN ACFT X AND ACFT Y. AS INDICATED IN THE ATTACHED LOGS; THE SAME PROB WITH AMASS WAS LOGGED ON NOV/SAT/91; AND CARRIED OVER IN SUBSEQUENT LOGS UNTIL IT WAS TAKEN OTS AT XA29Z ON NOV/MON/01. I WAS NOT BRIEFED ABOUT THE SIT WITH AMASS. I WAS NOT INSTRUCTED ON WHETHER TO REGARD OR DISREGARD ALERTS OF THIS NATURE; NOR WAS THE AMASS TAKEN OTS WHEN THE PROB FIRST OCCURRED; OR EVEN WHEN MAINT PERSONNEL CONFIRMED THE PROB. I DO ACCEPT RESPONSIBILITY FOR THE SIT ON THE RWY; HOWEVER; I AM ANGRY THAT AMASS -- THE EQUIP THAT'S SOLE PURPOSE IS TO PREVENT THIS TYPE OF OCCURRENCE -- ACTUALLY CREATED A DISTR THAT ALLOWED IT TO HAPPEN. ALSO; I AM DISTRESSED THAT IT WAS A KNOWN PROB FOR WHICH I HAD BEEN GIVEN NO DIRECTION.