Narrative:

Air carrier X initiated a climb of 300 ft as a result of a TCASII advisory and/or RA. The problem is that he knew about small transport X for at least 10 mi, he knew the traffic was restr below him, and he knew small transport Y had him in sight. (I had restr small transport Y and was talking to them both.) in spite of the information, he went ahead and complied with the advisory. My concern is that under some conditions, I, as a controller, would use min separation to expedite traffic or to effect a smooth orderly flow. If TCASII equipped aircraft are going to deviate even if they know the traffic is going to be kept out of their way then it has the potential to create conflict, especially in the terminal environment. Another TCASII situation occurred immediately afterwards when a TCASII equipped aircraft did not want to take a turn to the right because he saw a target on TCASII but it didn't have an altitude encoder. There was not anybody on my radar within 7 mi of him, and the heading that I wanted him to fly did not put him in conflict with anybody. His second guessing caused me to have to explain to him that there wasn't any traffic to be concerned about. By the time all was said and done, I was behind with the rest of my traffic. Not a good situation. The pilots are beginning to use TCASII to maintain the separation that is comfortable to them and not the separation that is mandated by the FAA. This is going to degrade the ability of controllers to provide for an orderly efficient flow.

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Original NASA ASRS Text

Title: ACR X NON ADHERENCE TO ATC CLRNC. PLTDEV. TCASII EXCURSION FROM ASSIGNED ALT.

Narrative: ACR X INITIATED A CLB OF 300 FT AS A RESULT OF A TCASII ADVISORY AND/OR RA. THE PROBLEM IS THAT HE KNEW ABOUT SMT X FOR AT LEAST 10 MI, HE KNEW THE TFC WAS RESTR BELOW HIM, AND HE KNEW SMT Y HAD HIM IN SIGHT. (I HAD RESTR SMT Y AND WAS TALKING TO THEM BOTH.) IN SPITE OF THE INFO, HE WENT AHEAD AND COMPLIED WITH THE ADVISORY. MY CONCERN IS THAT UNDER SOME CONDITIONS, I, AS A CTLR, WOULD USE MIN SEPARATION TO EXPEDITE TFC OR TO EFFECT A SMOOTH ORDERLY FLOW. IF TCASII EQUIPPED ACFT ARE GOING TO DEVIATE EVEN IF THEY KNOW THE TFC IS GOING TO BE KEPT OUT OF THEIR WAY THEN IT HAS THE POTENTIAL TO CREATE CONFLICT, ESPECIALLY IN THE TERMINAL ENVIRONMENT. ANOTHER TCASII SITUATION OCCURRED IMMEDIATELY AFTERWARDS WHEN A TCASII EQUIPPED ACFT DID NOT WANT TO TAKE A TURN TO THE R BECAUSE HE SAW A TARGET ON TCASII BUT IT DIDN'T HAVE AN ALT ENCODER. THERE WAS NOT ANYBODY ON MY RADAR WITHIN 7 MI OF HIM, AND THE HDG THAT I WANTED HIM TO FLY DID NOT PUT HIM IN CONFLICT WITH ANYBODY. HIS SECOND GUESSING CAUSED ME TO HAVE TO EXPLAIN TO HIM THAT THERE WASN'T ANY TFC TO BE CONCERNED ABOUT. BY THE TIME ALL WAS SAID AND DONE, I WAS BEHIND WITH THE REST OF MY TFC. NOT A GOOD SITUATION. THE PLTS ARE BEGINNING TO USE TCASII TO MAINTAIN THE SEPARATION THAT IS COMFORTABLE TO THEM AND NOT THE SEPARATION THAT IS MANDATED BY THE FAA. THIS IS GOING TO DEGRADE THE ABILITY OF CTLRS TO PROVIDE FOR AN ORDERLY EFFICIENT FLOW.

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.