Narrative:

When the FAA bought our communication system; the voice switching and communication system (vscs) a feature advertised by the vendor would permit discrete frequencys to be 'linked' to allow aircraft on one frequency to hear the xmissions on another and avoid blocking or garbling. I don't know if any of the en route ctrs in the western united states that have large sectors requiring multiple frequencys have this feature. Ny ARTCC does not have this feature. Normal operations at ZNY sector 91 require the controller to monitor 123.62; 124.9 and 134.8 en route sector frequencys; 118.55 clearance delivery frequency at unv and 121.5/243.0 emergency frequencys. Communicating on this many frequencys often presents a problem as aircraft on one frequency cannot hear aircraft on a different frequency. This often results in garbled xmissions and poses a threat of miscom that could result in an accident. Additionally; when sectors combine; the new frequencys come with them. On this particular evening; sector 92 had combined with sector 91 and 124.62 was now also in operation. Traffic level was moderate to heavy with aircraft operating on all frequencys except 123.62. Aircraft #1 was en route from phl to unv at 12000 ft on 124.62. Aircraft #2 was en route from pit to avp at 17000 ft. As aircraft #2 neared avf I descended him to 9000 ft. The readback was initially garbled with multiple aircraft talking. I deciphered both aircraft #2; reading back his descent clearance and another aircraft calling for clearance on 118.55. I felt that there was possibly a third aircraft involved as well; but couldn't identify it. Shortly thereafter; both air carrier #1 and air carrier #2 were observed descending. Thankfully; there was no traffic below air carrier #1 or separation error would have occurred. The similarity of these 2 call signs contributed to the miscom.

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Original NASA ASRS Text

Title: ZNY CTLR DESCRIBED POTENTIAL SEPARATION LOSS AT 12000 FT BTWN 2 ACFT BECAUSE OF SIMULTANEOUS USE OF MULTIPLE FREQS.

Narrative: WHEN THE FAA BOUGHT OUR COM SYS; THE VOICE SWITCHING AND COM SYS (VSCS) A FEATURE ADVERTISED BY THE VENDOR WOULD PERMIT DISCRETE FREQS TO BE 'LINKED' TO ALLOW ACFT ON ONE FREQ TO HEAR THE XMISSIONS ON ANOTHER AND AVOID BLOCKING OR GARBLING. I DON'T KNOW IF ANY OF THE ENRTE CTRS IN THE WESTERN UNITED STATES THAT HAVE LARGE SECTORS REQUIRING MULTIPLE FREQS HAVE THIS FEATURE. NY ARTCC DOES NOT HAVE THIS FEATURE. NORMAL OPS AT ZNY SECTOR 91 REQUIRE THE CTLR TO MONITOR 123.62; 124.9 AND 134.8 ENRTE SECTOR FREQS; 118.55 CLRNC DELIVERY FREQ AT UNV AND 121.5/243.0 EMER FREQS. COMMUNICATING ON THIS MANY FREQS OFTEN PRESENTS A PROB AS ACFT ON ONE FREQ CANNOT HEAR ACFT ON A DIFFERENT FREQ. THIS OFTEN RESULTS IN GARBLED XMISSIONS AND POSES A THREAT OF MISCOM THAT COULD RESULT IN AN ACCIDENT. ADDITIONALLY; WHEN SECTORS COMBINE; THE NEW FREQS COME WITH THEM. ON THIS PARTICULAR EVENING; SECTOR 92 HAD COMBINED WITH SECTOR 91 AND 124.62 WAS NOW ALSO IN OP. TFC LEVEL WAS MODERATE TO HVY WITH ACFT OPERATING ON ALL FREQS EXCEPT 123.62. ACFT #1 WAS ENRTE FROM PHL TO UNV AT 12000 FT ON 124.62. ACFT #2 WAS ENRTE FROM PIT TO AVP AT 17000 FT. AS ACFT #2 NEARED AVF I DSNDED HIM TO 9000 FT. THE READBACK WAS INITIALLY GARBLED WITH MULTIPLE ACFT TALKING. I DECIPHERED BOTH ACFT #2; READING BACK HIS DSCNT CLRNC AND ANOTHER ACFT CALLING FOR CLRNC ON 118.55. I FELT THAT THERE WAS POSSIBLY A THIRD ACFT INVOLVED AS WELL; BUT COULDN'T IDENT IT. SHORTLY THEREAFTER; BOTH ACR #1 AND ACR #2 WERE OBSERVED DSNDING. THANKFULLY; THERE WAS NO TFC BELOW ACR #1 OR SEPARATION ERROR WOULD HAVE OCCURRED. THE SIMILARITY OF THESE 2 CALL SIGNS CONTRIBUTED TO THE MISCOM.

Data retrieved from NASA's ASRS site as of January 2009 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.