ZMA controller described a TCAS RA event when no traffic was observed until changing to the darc sys...

Narrative:

A dash 8 was a mygf departure cleared on BR68V. The aircraft reported on at 6;000 ft level east of munro and was called radar by the r-side. When the dash 8 got near the munro intersection the aircraft said they were responding to an RA and they climbed to 6;600 ft MSL. At this time we showed no traffic on the radar scope that would be traffic. After the dash 8 said he was clear of the traffic; I asked the r-side to switch to darc mode and then we saw the traffic at 5;700 ft MSL just northwest of munro already past the dash 8. When we switched back to the primary radar we saw the traffic pop up 3 miles east of munro for a few hits then it disappeared again. This is not the first time that our backup system has had better radar then our primary system. This happens all the time but is never fixed. Its a real safety issue that we have to always switch between our darc and primary radar system to see limited targets. This is a known problem and from what I can remember we were told that it will not be fixed till eram is being used. It's not a safe situation and it needs to be addressed.

Original NASA ASRS Text

Title: ZMA Controller described a TCAS RA event when no traffic was observed until changing to the DARC system which did display a target; the reporter noting the back up DARC RADAR system is superior to the primary.

Narrative: A Dash 8 was a MYGF departure cleared on BR68V. The aircraft reported on at 6;000 FT level east of MUNRO and was called RADAR by the R-side. When the Dash 8 got near the MUNRO Intersection the aircraft said they were responding to an RA and they climbed to 6;600 FT MSL. At this time we showed no traffic on the RADAR scope that would be traffic. After the Dash 8 said he was clear of the traffic; I asked the R-Side to switch to DARC mode and then we saw the traffic at 5;700 FT MSL just northwest of MUNRO already past the Dash 8. When we switched back to the Primary RADAR we saw the traffic pop up 3 miles east of MUNRO for a few hits then it disappeared again. This is not the first time that our backup system has had better RADAR then our primary system. This happens all the time but is never fixed. Its a real safety issue that we have to always switch between our DARC and primary RADAR system to see limited targets. This is a known problem and from what I can remember we were told that it will not be fixed till ERAM is being used. It's not a safe situation and it needs to be addressed.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	909444
Time
Date	201009
Local Time Of Day	1801-2400
Place
Locale Reference	ZMA.ARTCC
State Reference	FL
Aircraft 1
Make Model Name	Dash 8 Series Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	None
Flight Plan	IFR
Person 1
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types

ZMA controller described a TCAS RA event when no traffic was observed until changing to the darc system which did display a target; the reporter noting the back up darc radar system is superior to the primary.