Narrative:

Aircraft X was entering the left downwind over the approach end of runway 17 when aircraft Y called for takeoff clearance. I issued the downwind traffic to aircraft Y and cleared him for takeoff. Aircraft Y turned slowly on the runway and began a slow roll, so I checked the progress of aircraft X who was turning a 1 mi final at a higher than normal altitude. I asked aircraft X if she would be able to land from that altitude. She responded yes, and asked for a long landing which I acknowledged. At this time 'amass' alarmed a go around, runway 35, runway occupied. Fearing a crossing situation or unknown aircraft for runway 35 with my departure, I immediately scanned to the south. The final was a bit hazy and I saw no aircraft or vehicle on or near runway 35. Aircraft Y then reported that he had aborted takeoff. I immediately sent aircraft X around and told her to fly to the east. Aircraft Y again reported the aborted takeoff. I told aircraft X to go around, at which time she reported on the ground. She landed just north of taxiway K5 and aircraft Y was still on the runway just south of taxiway K8. At the time amass alarmed, I believed that aircraft Y was departing and that I had sufficient time to correct the situation if necessary. I had 2 other aircraft on frequency and no other potential conflicts with known traffic. When amass alarmed for runway 35, my attention was immediately diverted to the priority of a mandatory go around for runway 35. I turned to the approach end of runway 35 to scan for unknown crossing traffic or arriving aircraft. I did not send any aircraft around as I was talking to no arrival aircraft on runway 35. In fact, my first concern was that whatever had caused this event on runway 35 was a potential collision with my departing traffic. I do not know why aircraft Y did not depart in a timely manner. It was nearly 2 mins after he received takeoff clearance before he reported aborting takeoff. I do not know why aircraft X landed over aircraft Y, except that she was high and I assume that she did not see the aircraft near the approach end of runway 17. I do not know why amass alarmed for runway 35 when we were in a south flow and using runway 17. We have been taught that this system is so accurate that we are required to issue a go around even if we believe that sufficient spacing will exist. I allowed this confusing alarm to distract my attention from my first priority, ensuring separation between aircraft X and aircraft Y. As indicated in the attached logs, the same problem 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 situation with amass. I was not instructed on whether to regard or disregard alerts of this nature, nor was the amass taken OTS when the problem first occurred, or even when maintenance personnel confirmed the problem. I do accept responsibility for the situation on the runway, however, I am angry that amass -- the equipment that's sole purpose is to prevent this type of occurrence -- actually created a distraction that allowed it to happen. Also, I am distressed that it was a known problem for which I had been given no direction.

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Original NASA ASRS Text

Title: 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.

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.