Narrative:

While working the R44 sector I was involved in a situation in which FAA approved sep was not maintained. The flts involved were air carrier Y and air carrier X. This situation was due in large part by the fact that air carrier Y was not monitoring frequency 132.15 which he was quoted as stating 'it was our mistake.' in attempting to secure sep, air carrier X was issued an immediate descent from assigned altitude of FL350 to FL330, but air carrier X was not able to achieve full compliance prior to approved sep being lost. The fact that there was only 90 seconds from beginning to end of this situation the FAA found the controller to be fully at fault. Supplemental information from acn 156726. The controller tried repeatedly to contact his sebnd traffic for a clearing turn. The controller then turned us 30 degree right. The controller then tried more contacts with his sebnd traffic with no success. My flight was then turned to 360 degree and told descend immediately to 33000' which we did. During our descent to FL330 I saw the sebnd aircraft at our 9:30 to 10:00 position at about 3-4 mi and passing to our left. Supplemental information from acn 156968. Upon checking in with center, we were assigned a heading to intercept the arwy south of lit. Only a few mins later we were given a 185 degree heading. Shortly thereafter, I put the new frequency, or so I thought, on the #1 radio and returned all switches to the 'normal' position. We were once again transmitting and receiving on #1 and #2 was set for a backup and unmonitored. Several mins later we both observed a heavy aircraft approximately at 3 mi. We weren't sure of the altitude, but assumed he was probably at FL330 since we were at fl 350. Shortly thereafter, the copilot attempted to verify that we were still on an assigned heading and received no reply. After the second attempt, I looked down to verify switch position and frequency and noticed that I had incorrectly set 135.12 in the #1 frequency selector instead of 132.12.

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Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR. ACR Y FLT CREW FAILED TO MONITOR ASSIGNED FREQ. PLTDEV.

Narrative: WHILE WORKING THE R44 SECTOR I WAS INVOLVED IN A SITUATION IN WHICH FAA APPROVED SEP WAS NOT MAINTAINED. THE FLTS INVOLVED WERE ACR Y AND ACR X. THIS SITUATION WAS DUE IN LARGE PART BY THE FACT THAT ACR Y WAS NOT MONITORING FREQ 132.15 WHICH HE WAS QUOTED AS STATING 'IT WAS OUR MISTAKE.' IN ATTEMPTING TO SECURE SEP, ACR X WAS ISSUED AN IMMEDIATE DSNT FROM ASSIGNED ALT OF FL350 TO FL330, BUT ACR X WAS NOT ABLE TO ACHIEVE FULL COMPLIANCE PRIOR TO APPROVED SEP BEING LOST. THE FACT THAT THERE WAS ONLY 90 SECS FROM BEGINNING TO END OF THIS SITUATION THE FAA FOUND THE CTLR TO BE FULLY AT FAULT. SUPPLEMENTAL INFO FROM ACN 156726. THE CTLR TRIED REPEATEDLY TO CONTACT HIS SEBND TFC FOR A CLRING TURN. THE CTLR THEN TURNED US 30 DEG R. THE CTLR THEN TRIED MORE CONTACTS WITH HIS SEBND TFC WITH NO SUCCESS. MY FLT WAS THEN TURNED TO 360 DEG AND TOLD DSND IMMEDIATELY TO 33000' WHICH WE DID. DURING OUR DSNT TO FL330 I SAW THE SEBND ACFT AT OUR 9:30 TO 10:00 POS AT ABOUT 3-4 MI AND PASSING TO OUR L. SUPPLEMENTAL INFO FROM ACN 156968. UPON CHKING IN WITH CTR, WE WERE ASSIGNED A HDG TO INTERCEPT THE ARWY S OF LIT. ONLY A FEW MINS LATER WE WERE GIVEN A 185 DEG HDG. SHORTLY THEREAFTER, I PUT THE NEW FREQ, OR SO I THOUGHT, ON THE #1 RADIO AND RETURNED ALL SWITCHES TO THE 'NORMAL' POS. WE WERE ONCE AGAIN XMITTING AND RECEIVING ON #1 AND #2 WAS SET FOR A BACKUP AND UNMONITORED. SEVERAL MINS LATER WE BOTH OBSERVED A HVY ACFT APPROX AT 3 MI. WE WEREN'T SURE OF THE ALT, BUT ASSUMED HE WAS PROBABLY AT FL330 SINCE WE WERE AT FL 350. SHORTLY THEREAFTER, THE COPLT ATTEMPTED TO VERIFY THAT WE WERE STILL ON AN ASSIGNED HDG AND RECEIVED NO REPLY. AFTER THE SEC ATTEMPT, I LOOKED DOWN TO VERIFY SWITCH POS AND FREQ AND NOTICED THAT I HAD INCORRECTLY SET 135.12 IN THE #1 FREQ SELECTOR INSTEAD OF 132.12.

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.