Narrative:

Standard sep was lost with air carrier X and air carrier Y. Relevant points; at least one pilot reported the other aircraft in sight, this may have caused a false sense of security for that pilot. Also, at least one aircraft had and was using TCAS, again, this may have slowed the pilot's response (compliance) with the clearance. Controller reactions should have been better. Air carrier X southbound level at FL290, air carrier Y level at FL310 westbound. I was working the ape/lck/ih/sh sectors, instructing a trnee (radar). The trnee cleared air carrier Y to descend to FL240 just after a 15 degree turn to the right for spacing. Both aircraft were issued 30 degree turns to the right initially. Air carrier X was then turned to a 100 degree heading, and air carrier Y was turned to a 240 degree heading. Standard sep was lost. The controller in this situation feels that the descent of air carrier Y was not a good decision if not accompanied with a turn clearance and a turn and climb clearance for the air carrier X aircraft. Supplemental information from acn 178140. Air carrier X southbound over apr VOR, FL290. Air carrier Y westbound 15 mi south of apr VOR, FL310 on this day, the fifth day of my radar training, I had been plugged in at the sector with my instrument for approximately 5 mins. Air carrier X requested FL330, however, air carrier Y was traffic at FL310. I descended air carrier X to FL240, intending to climb air carrier Y when clear. Turns which were necessary to insure standard sep were not issued until my instrument stepped in shortly thereafter. Each aircraft was turned 30 degree left then an additional 30 degree left, as air carrier X was climbed to FL330. Altitude reports showed air carrier X out of FL310 while air carrier Y out of FL297. Air carrier X reported their TCAS instruments showed more than 7 mi throughout the incident. Official FAA results concluded a minimum of 4.1 mi and 300' sep.

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Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: STANDARD SEP WAS LOST WITH ACR X AND ACR Y. RELEVANT POINTS; AT LEAST ONE PLT RPTED THE OTHER ACFT IN SIGHT, THIS MAY HAVE CAUSED A FALSE SENSE OF SECURITY FOR THAT PLT. ALSO, AT LEAST ONE ACFT HAD AND WAS USING TCAS, AGAIN, THIS MAY HAVE SLOWED THE PLT'S RESPONSE (COMPLIANCE) WITH THE CLRNC. CTLR REACTIONS SHOULD HAVE BEEN BETTER. ACR X SBND LEVEL AT FL290, ACR Y LEVEL AT FL310 WBND. I WAS WORKING THE APE/LCK/IH/SH SECTORS, INSTRUCTING A TRNEE (RADAR). THE TRNEE CLRED ACR Y TO DSND TO FL240 JUST AFTER A 15 DEG TURN TO THE R FOR SPACING. BOTH ACFT WERE ISSUED 30 DEG TURNS TO THE R INITIALLY. ACR X WAS THEN TURNED TO A 100 DEG HDG, AND ACR Y WAS TURNED TO A 240 DEG HDG. STANDARD SEP WAS LOST. THE CTLR IN THIS SITUATION FEELS THAT THE DSNT OF ACR Y WAS NOT A GOOD DECISION IF NOT ACCOMPANIED WITH A TURN CLRNC AND A TURN AND CLB CLRNC FOR THE ACR X ACFT. SUPPLEMENTAL INFO FROM ACN 178140. ACR X SBND OVER APR VOR, FL290. ACR Y WBND 15 MI S OF APR VOR, FL310 ON THIS DAY, THE FIFTH DAY OF MY RADAR TRNING, I HAD BEEN PLUGGED IN AT THE SECTOR WITH MY INSTR FOR APPROX 5 MINS. ACR X REQUESTED FL330, HOWEVER, ACR Y WAS TFC AT FL310. I DSNDED ACR X TO FL240, INTENDING TO CLB ACR Y WHEN CLR. TURNS WHICH WERE NECESSARY TO INSURE STANDARD SEP WERE NOT ISSUED UNTIL MY INSTR STEPPED IN SHORTLY THEREAFTER. EACH ACFT WAS TURNED 30 DEG L THEN AN ADDITIONAL 30 DEG L, AS ACR X WAS CLBED TO FL330. ALT REPORTS SHOWED ACR X OUT OF FL310 WHILE ACR Y OUT OF FL297. ACR X RPTED THEIR TCAS INSTRUMENTS SHOWED MORE THAN 7 MI THROUGHOUT THE INCIDENT. OFFICIAL FAA RESULTS CONCLUDED A MINIMUM OF 4.1 MI AND 300' SEP.

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.