Narrative:

Air carrier X was established in the holding pattern at helon intersection. Atx Y was issued a heading of 180 degree to join V489 to weard intersection to hold north with right turns. Had atx Y joined the airway as instructed at least 8 mi separation would have existed. By the time I observed atx Y southeast of the airway and decided to take action, an aircraft tied up the frequency for 25 seconds with a question about his hold. I then called air carrier X twice to turn with no response. Atx Y was then instructed to turn immediately and complied, a third call to air carrier X revealed he was on frequency but had not heard the previous call. He then turned immediately. Both aircraft were at 9000 with traffic above at 10 and below at 8. Also, air carrier X had missed 2 previous calls when I initially put him in the holding pattern. All pilots should listen for their call sign even if they don't want to hold. The traffic management unit (flow control) should keep abreast of all potential saturation situations. And controllers should never hold aircraft at the same altitude unless the holding patterns are separated by enough miles to catch any strays.

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Original NASA ASRS Text

Title: ACFT WERE CLEARED IN DIFFERENT HOLDING PATTERNS AT THE SAME ALT. THE PATTERNS CONFLICTED WITH EACH OTHER.

Narrative: ACR X WAS ESTABLISHED IN THE HOLDING PATTERN AT HELON INTXN. ATX Y WAS ISSUED A HDG OF 180 DEG TO JOIN V489 TO WEARD INTXN TO HOLD N WITH RIGHT TURNS. HAD ATX Y JOINED THE AIRWAY AS INSTRUCTED AT LEAST 8 MI SEPARATION WOULD HAVE EXISTED. BY THE TIME I OBSERVED ATX Y SE OF THE AIRWAY AND DECIDED TO TAKE ACTION, AN ACFT TIED UP THE FREQ FOR 25 SECONDS WITH A QUESTION ABOUT HIS HOLD. I THEN CALLED ACR X TWICE TO TURN WITH NO RESPONSE. ATX Y WAS THEN INSTRUCTED TO TURN IMMEDIATELY AND COMPLIED, A THIRD CALL TO ACR X REVEALED HE WAS ON FREQ BUT HAD NOT HEARD THE PREVIOUS CALL. HE THEN TURNED IMMEDIATELY. BOTH ACFT WERE AT 9000 WITH TFC ABOVE AT 10 AND BELOW AT 8. ALSO, ACR X HAD MISSED 2 PREVIOUS CALLS WHEN I INITIALLY PUT HIM IN THE HOLDING PATTERN. ALL PLTS SHOULD LISTEN FOR THEIR CALL SIGN EVEN IF THEY DON'T WANT TO HOLD. THE TFC MGMNT UNIT (FLOW CTL) SHOULD KEEP ABREAST OF ALL POTENTIAL SATURATION SITUATIONS. AND CTLRS SHOULD NEVER HOLD ACFT AT THE SAME ALT UNLESS THE HOLDING PATTERNS ARE SEPARATED BY ENOUGH MILES TO CATCH ANY STRAYS.

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.