Narrative:

Here is my rationale; and I would appreciate a national understanding of these events. As a controller I have 3 things to base my decisions on: 1) histories; 2) expectations (I'm not clairvoyant); 3) ability to effect plan B and C. It is my understanding that an 'orbit' is a continuous track in one direction; see circle. This is fully defined in webster's; and by society; (ie; the moon orbits the earth). There are some instances where I have found in military mou's that an 'orbit' other than a continuous circle; requires prior specific coordination with ATC. This being written; seems to lend itself to the possibility that if it were truly understood that an 'orbit' was the same as a 'delay' where the pilot has carte blanche to do as he pleases; there would be no need for this definition to be present in an mou. Also; if the FAA and the flying public (and military) are using a definition other than that accepted by everyone else; this 'new definition' should be defined in our 7110.65; aim; military operations manual; etc. In fact; I can find no such definition of this sort. Therefore; I believe that I should have had a working expectation that a request to orbit that was approved as requested should have been flown in a continuous track. If it had been flown this way I would have had the ability to initiate my plan B or plan C; both of which I had in my head when I issued the clearance. Next; I believe that an aircraft flying on an IFR flight plan on an IFR clearance has a responsibility as per the aim to operate straight and level and turns at a standard rate; unless previously coordination. This action would have resulted in a 1-MIN turn around rather than the 10-second turn I experienced. Again taking away my working expectation and possibly my ability to initiate plan B or plan C. On this date I had air carrier X stopped at FL280 and aircraft Y stopped at FL300; cleared to 'orbit' for descent. It made 2 complete left turns. I had a j-ring on air carrier X and when aircraft Y cleared the ring; I issued a descent to FL260. It immediately turned a 180 degree turn to the right and descended at a very high rate right in front of air carrier X. I tried to stop the descent but was too late and issued a turn away from traffic. Air carrier X reacted to an RA from his TCAS and climbed. Aircraft swapped altitudes.

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Original NASA ASRS Text

Title: ZOA CTLR DESCRIBED OPERROR AT FL280 WHEN AN ACFT GIVEN A DESCENT CLRNC MADE AN UNEXPECTED TIGHT TURN CONFLICTING WITH SUCCEEDING TFC.

Narrative: HERE IS MY RATIONALE; AND I WOULD APPRECIATE A NATIONAL UNDERSTANDING OF THESE EVENTS. AS A CTLR I HAVE 3 THINGS TO BASE MY DECISIONS ON: 1) HISTORIES; 2) EXPECTATIONS (I'M NOT CLAIRVOYANT); 3) ABILITY TO EFFECT PLAN B AND C. IT IS MY UNDERSTANDING THAT AN 'ORBIT' IS A CONTINUOUS TRACK IN ONE DIRECTION; SEE CIRCLE. THIS IS FULLY DEFINED IN WEBSTER'S; AND BY SOCIETY; (IE; THE MOON ORBITS THE EARTH). THERE ARE SOME INSTANCES WHERE I HAVE FOUND IN MIL MOU'S THAT AN 'ORBIT' OTHER THAN A CONTINUOUS CIRCLE; REQUIRES PRIOR SPECIFIC COORD WITH ATC. THIS BEING WRITTEN; SEEMS TO LEND ITSELF TO THE POSSIBILITY THAT IF IT WERE TRULY UNDERSTOOD THAT AN 'ORBIT' WAS THE SAME AS A 'DELAY' WHERE THE PLT HAS CARTE BLANCHE TO DO AS HE PLEASES; THERE WOULD BE NO NEED FOR THIS DEFINITION TO BE PRESENT IN AN MOU. ALSO; IF THE FAA AND THE FLYING PUBLIC (AND MIL) ARE USING A DEFINITION OTHER THAN THAT ACCEPTED BY EVERYONE ELSE; THIS 'NEW DEFINITION' SHOULD BE DEFINED IN OUR 7110.65; AIM; MIL OPS MANUAL; ETC. IN FACT; I CAN FIND NO SUCH DEFINITION OF THIS SORT. THEREFORE; I BELIEVE THAT I SHOULD HAVE HAD A WORKING EXPECTATION THAT A REQUEST TO ORBIT THAT WAS APPROVED AS REQUESTED SHOULD HAVE BEEN FLOWN IN A CONTINUOUS TRACK. IF IT HAD BEEN FLOWN THIS WAY I WOULD HAVE HAD THE ABILITY TO INITIATE MY PLAN B OR PLAN C; BOTH OF WHICH I HAD IN MY HEAD WHEN I ISSUED THE CLRNC. NEXT; I BELIEVE THAT AN ACFT FLYING ON AN IFR FLT PLAN ON AN IFR CLRNC HAS A RESPONSIBILITY AS PER THE AIM TO OPERATE STRAIGHT AND LEVEL AND TURNS AT A STANDARD RATE; UNLESS PREVIOUSLY COORD. THIS ACTION WOULD HAVE RESULTED IN A 1-MIN TURN AROUND RATHER THAN THE 10-SECOND TURN I EXPERIENCED. AGAIN TAKING AWAY MY WORKING EXPECTATION AND POSSIBLY MY ABILITY TO INITIATE PLAN B OR PLAN C. ON THIS DATE I HAD ACR X STOPPED AT FL280 AND ACFT Y STOPPED AT FL300; CLRED TO 'ORBIT' FOR DSCNT. IT MADE 2 COMPLETE L TURNS. I HAD A J-RING ON ACR X AND WHEN ACFT Y CLRED THE RING; I ISSUED A DSCNT TO FL260. IT IMMEDIATELY TURNED A 180 DEG TURN TO THE R AND DSNDED AT A VERY HIGH RATE RIGHT IN FRONT OF ACR X. I TRIED TO STOP THE DSCNT BUT WAS TOO LATE AND ISSUED A TURN AWAY FROM TFC. ACR X REACTED TO AN RA FROM HIS TCAS AND CLBED. ACFT SWAPPED ALTS.

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.