An rdu controller described a developing conflict when rarar targets were not accurately tracking su...

Narrative:

Air carrier Y was on the ILS runway 23L; approximately on a five mile final and had received landing clearance. M20E was issued take off clearance runway 23L and assigned heading 160. Air carrier Z was cleared for take off runway 23R assigned heading 230. Meanwhile air carrier Y indicated he was going missed approach. During this time M20E; who was about 1 1/2 miles on the departure end; was tracking 230 degrees; instead of the 160 degrees assigned. I was working very hard to ensure that M20E was turning left to the 160 heading because I knew that if he wasn't; he would conflict with air carrier Z and air carrier Y. Air carrier Z was issued a 270 heading to avoid a confliction with M20E and air carrier Y. Air carrier Y was issued a 230 to avoid confliction with M20E and air carrier Z. This incident occurred in IFR conditions. It is my belief that because we were using fused/ads-B radar; the targets were not tracking the accurate position of these aircraft. When M20E was issued a beacon code change; his target began to track right of course. When air carrier Y went missed approach; his target indicated an isr or 'increase radar separation.' prior to this incident; I have noticed many targets constantly moving left/right of course and a few that move backwards. Unless this problem is fixed; I recommend that we do not use fused/ads-B.

Original NASA ASRS Text

Title: An RDU Controller described a developing conflict when RARAR targets were not accurately tracking suggesting the FUSED/ADS-B RADAR was causing the anomaly.

Narrative: Air Carrier Y was on the ILS Runway 23L; approximately on a five mile final and had received landing clearance. M20E was issued take off clearance Runway 23L and assigned heading 160. Air Carrier Z was cleared for take off Runway 23R assigned heading 230. Meanwhile Air Carrier Y indicated he was going missed approach. During this time M20E; who was about 1 1/2 miles on the departure end; was tracking 230 degrees; instead of the 160 degrees assigned. I was working very hard to ensure that M20E was turning left to the 160 heading because I knew that if he wasn't; he would conflict with Air Carrier Z and Air Carrier Y. Air Carrier Z was issued a 270 heading to avoid a confliction with M20E and Air Carrier Y. Air Carrier Y was issued a 230 to avoid confliction with M20E and Air Carrier Z. This incident occurred in IFR conditions. It is my belief that because we were using FUSED/ADS-B RADAR; the targets were not tracking the accurate position of these aircraft. When M20E was issued a beacon code change; his target began to track right of course. When Air Carrier Y went missed approach; his target indicated an ISR or 'increase RADAR separation.' Prior to this incident; I have noticed many targets constantly moving left/right of course and a few that move backwards. Unless this problem is fixed; I recommend that we do not use FUSED/ADS-B.

Data retrieved from NASA's ASRS site as of July 2013 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	1060227
Time
Date	201301
Local Time Of Day	1801-2400
Place
Locale Reference	RDU.Airport
State Reference	NC
Aircraft 1
Make Model Name	M-20 G Statesman
Flight Phase	Initial Climb
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance Deviation - Track / Heading All Types

An rdu controller described a developing conflict when rarar targets were not accurately tracking suggesting the fused/ads-B radar was causing the anomaly.