Narrative:

Radar OJT was being conducted at the time of occurrence. Air carrier X and cga Y were both on assigned headings for additional traffic at FL370. (Cga Y was requesting FL390 but was too heavy to climb non-stop and was moved from FL350 to FL370 to avoid other traffic at FL350.) when air carrier X and cga Y were approximately 30 mi from the point of confliction, as the developmental controller attempted to issue a vector to air carrier X to clear cga Y, it became apparent that we had some sort of communications problem. Many attempts were made to contact any/all aircraft on frequency using primary, secondary, and buec equipment - all to no avail. We were able to determine that our receivers were operating normally but that we were unable to transmit by all means available to us. The area supervisor attempted to transmit from the overhead position but it was also inoperative. We instructed an adjacent sector to send an aircraft to 128.775 and relay a clearance for air carrier X to descend to FL350 and fly a 180 degree heading. During the confusion that existed on the frequency by many aircraft calling repeatedly without a response from us, air carrier X had gone over to the mystic sector frequency. At the time the targets were about to merge at FL370 (very scary!), the mystic controller called us to advise that he was communicating with air carrier X. We told him to immediately descend air carrier X to FL350 which he did. Closest proximity was supposedly 2.1 mi and 100' or less. Frequencys at our facility fail or are unusable for a variety of reasons on a regular (daily) basis and it was only through the grace of god and judicial application of the 'big sky theory' that a tragedy was averted here. We absolutely must have better communications equipment if we are to provide the level of safety expected of us. I have noted that, since this incident occurred, supervisors are not logging on the area daily log reports minor (and in one case major) frequency problems. Is this an attempt to reduce the documentation on and therefore evidence of serious equipment problems?

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Original NASA ASRS Text

Title: ATC TRANSMITTER FAILURE OCCURRED WHILE TWO ACFT AT SAME ALT WERE ON CONVERGING COURSES.

Narrative: RADAR OJT WAS BEING CONDUCTED AT THE TIME OF OCCURRENCE. ACR X AND CGA Y WERE BOTH ON ASSIGNED HDGS FOR ADDITIONAL TFC AT FL370. (CGA Y WAS REQUESTING FL390 BUT WAS TOO HEAVY TO CLIMB NON-STOP AND WAS MOVED FROM FL350 TO FL370 TO AVOID OTHER TFC AT FL350.) WHEN ACR X AND CGA Y WERE APPROX 30 MI FROM THE POINT OF CONFLICTION, AS THE DEVELOPMENTAL CTLR ATTEMPTED TO ISSUE A VECTOR TO ACR X TO CLEAR CGA Y, IT BECAME APPARENT THAT WE HAD SOME SORT OF COMS PROBLEM. MANY ATTEMPTS WERE MADE TO CONTACT ANY/ALL ACFT ON FREQ USING PRIMARY, SECONDARY, AND BUEC EQUIPMENT - ALL TO NO AVAIL. WE WERE ABLE TO DETERMINE THAT OUR RECEIVERS WERE OPERATING NORMALLY BUT THAT WE WERE UNABLE TO XMIT BY ALL MEANS AVAILABLE TO US. THE AREA SUPVR ATTEMPTED TO XMIT FROM THE OVERHEAD POSITION BUT IT WAS ALSO INOPERATIVE. WE INSTRUCTED AN ADJACENT SECTOR TO SEND AN ACFT TO 128.775 AND RELAY A CLRNC FOR ACR X TO DSND TO FL350 AND FLY A 180 DEG HDG. DURING THE CONFUSION THAT EXISTED ON THE FREQ BY MANY ACFT CALLING REPEATEDLY WITHOUT A RESPONSE FROM US, ACR X HAD GONE OVER TO THE MYSTIC SECTOR FREQ. AT THE TIME THE TARGETS WERE ABOUT TO MERGE AT FL370 (VERY SCARY!), THE MYSTIC CTLR CALLED US TO ADVISE THAT HE WAS COMMUNICATING WITH ACR X. WE TOLD HIM TO IMMEDIATELY DSND ACR X TO FL350 WHICH HE DID. CLOSEST PROX WAS SUPPOSEDLY 2.1 MI AND 100' OR LESS. FREQS AT OUR FAC FAIL OR ARE UNUSABLE FOR A VARIETY OF REASONS ON A REGULAR (DAILY) BASIS AND IT WAS ONLY THROUGH THE GRACE OF GOD AND JUDICIAL APPLICATION OF THE 'BIG SKY THEORY' THAT A TRAGEDY WAS AVERTED HERE. WE ABSOLUTELY MUST HAVE BETTER COMS EQUIPMENT IF WE ARE TO PROVIDE THE LEVEL OF SAFETY EXPECTED OF US. I HAVE NOTED THAT, SINCE THIS INCIDENT OCCURRED, SUPVRS ARE NOT LOGGING ON THE AREA DAILY LOG REPORTS MINOR (AND IN ONE CASE MAJOR) FREQ PROBLEMS. IS THIS AN ATTEMPT TO REDUCE THE DOCUMENTATION ON AND THEREFORE EVIDENCE OF SERIOUS EQUIPMENT PROBLEMS?

Data retrieved from NASA's ASRS site as of August 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.