Narrative:

Aircraft X departed lex assigned 050 for crossing traffic that was pointed out to tower. Crossing traffic was aircraft Y. Traffic was issued to both aircraft by radar east. Shortly after; aircraft Y reported the aircraft X in sight. As legal class C separation of 500 feet vertical was being maintained; aircraft Y was not instructed to maintain visual separation as it was not required. Aircraft X was advised aircraft Y had him in sight but aircraft X immediately reported he was responding to RA and descending. The pilot of aircraft X stated that even he was confused why his TCAS was commanding an RA in this situation. No loss of separation occurred.this is all too common an occurrence in class C radar environments. It's getting so that we either have to provide 3 miles or 1;000 feet between IFR/VFR aircraft or else the IFR will report they're responding to a TCAS RA for a non-event. I honestly have no idea what could be done to fix the issue. It's not like we want to go back to the days of giving the pilots an option to follow or not follow TCAS ras; but perhaps there needs to be a system setting for class C/D airspace and class a/B airspace environments. Given that the pilot of the aircraft X sounded perplexed as to why he was getting an RA; and the frequency at which this type of event occurs; it doesn't seem too farfetched to consider that maybe pilots are getting tired of such 'the boy yelled wolf!' scenarios. At what point do such nuisance/unwarranted ras cause pilots to lose faith in the RA system; or induce a false sense of complacency when responding to them?

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Original NASA ASRS Text

Title: A LEX Tower Controller reports of an airborne conflict that traffic has been issued to. One of the two aircraft sees the other. The other aircraft gets an RA and descends. Legal separation was continued but the Controller is reporting that this type of conflict happens all the time in the Class C environment. The Controller is concerned about the 'boy yelling wolf' scenario that pilots might lose faith in the RA System.

Narrative: Aircraft X departed LEX assigned 050 for crossing traffic that was pointed out to tower. Crossing traffic was aircraft Y. Traffic was issued to both aircraft by radar east. Shortly after; aircraft Y reported the aircraft X in sight. As legal class C separation of 500 feet vertical was being maintained; aircraft Y was not instructed to maintain visual separation as it was not required. Aircraft X was advised aircraft Y had him in sight but aircraft X immediately reported he was responding to RA and descending. The pilot of aircraft X stated that even he was confused why his TCAS was commanding an RA in this situation. No loss of separation occurred.This is all too common an occurrence in Class C radar environments. It's getting so that we either have to provide 3 miles or 1;000 feet between IFR/VFR aircraft or else the IFR will report they're responding to a TCAS RA for a non-event. I honestly have no idea what could be done to fix the issue. It's not like we want to go back to the days of giving the pilots an option to follow or not follow TCAS RAs; but perhaps there needs to be a system setting for Class C/D airspace and Class A/B airspace environments. Given that the pilot of the Aircraft X sounded perplexed as to why he was getting an RA; and the frequency at which this type of event occurs; it doesn't seem too farfetched to consider that maybe pilots are getting tired of such 'the boy yelled wolf!' scenarios. At what point do such nuisance/unwarranted RAs cause pilots to lose faith in the RA system; or induce a false sense of complacency when responding to them?

Data retrieved from NASA's ASRS site 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.