Narrative:

I was assigned aircraft X which was in maintenance in ZZZ and expected to be released that afternoon. I noticed that the TCAS had been deferred; and after check in; I contacted maintenance control to confirm that they would be clearing this MEL. The controller did not believe that this was in the work scope for that day. This was an [MEL category] C item and would not have to be cleared until after my tour in this aircraft was over. It was scheduled to perform numerous flights with the TCAS deferred.I firmly believe that this MEL poses a potential safety issue; as we frequently operate in very busy and complex airspace shared with VFR aircraft which are not being controlled nor in communication with ATC. And even if ATC is in communication with these aircraft; they may be too busy to point out or effect evasive vectors to avoid a conflict. I have experienced numerous RA's over the years in which we did not see the encroaching aircraft and TCAS alone avoided a potential midair collision. I sent a message to the [company] safety department and the safety committee requesting that this item be fixed prior to any flights for the reasons mentioned; especially since it was already in maintenance. I clarified that I was not refusing the flight; but my preference would be to repair this issue now. I also questioned if the large cabin aircraft were subject to the same MEL. I received emails back stating that the same MEL for the large cabin was a category B MEL; and in some international operations; it was aog [grounding item]. This seems to be somewhat of a double standard. Also; they explained that the FAA had approved this mmel deferral through a 'risk assessment;' thus allowing the [company] MEL. Obviously I disagree with this risk assessment. After all; the requirement for TCAS came about years ago following a midair collision when the airspace was even less congested than now.I then received a revised brief and email stating that we would be ferrying the aircraft to a service center in ZZZ1 for the repairs to be made. This made good sense; and that flight was conducted.

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Original NASA ASRS Text

Title: CE680 Captain reported requested an inoperative TCAS system be repaired prior to returning to revenue service.

Narrative: I was assigned Aircraft X which was in maintenance in ZZZ and expected to be released that afternoon. I noticed that the TCAS had been deferred; and after check in; I contacted Maintenance Control to confirm that they would be clearing this MEL. The Controller did not believe that this was in the work scope for that day. This was an [MEL Category] C item and would not have to be cleared until after my tour in this aircraft was over. It was scheduled to perform numerous flights with the TCAS deferred.I firmly believe that this MEL poses a potential safety issue; as we frequently operate in very busy and complex airspace shared with VFR aircraft which are not being controlled nor in communication with ATC. And even if ATC is in communication with these aircraft; they may be too busy to point out or effect evasive vectors to avoid a conflict. I have experienced numerous RA's over the years in which we did not see the encroaching aircraft and TCAS alone avoided a potential midair collision. I sent a message to the [Company] Safety department and the Safety committee requesting that this item be fixed prior to any flights for the reasons mentioned; especially since it was already in maintenance. I clarified that I was not refusing the flight; but my preference would be to repair this issue now. I also questioned if the large cabin aircraft were subject to the same MEL. I received emails back stating that the same MEL for the Large Cabin was a Category B MEL; and in some international operations; it was AOG [Grounding item]. This seems to be somewhat of a double standard. Also; they explained that the FAA had approved this MMEL deferral through a 'Risk Assessment;' thus allowing the [Company] MEL. Obviously I disagree with this risk assessment. After all; the requirement for TCAS came about years ago following a midair collision when the airspace was even less congested than now.I then received a revised Brief and email stating that we would be ferrying the aircraft to a Service Center in ZZZ1 for the repairs to be made. This made good sense; and that flight was conducted.

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.