Narrative:

I was working departure, radar at gulfport approach gulfport, ms. A T34 departed runway 14 heading 270 degrees. At the same time a military aircraft at the same altitude was inbound on the ILS for runway 14, 6 mi northwest. The beacon code and mode C altitude jumped 4 mi northwest right in front of the ffj. But the aircraft was really 7 mi west of gpt, plus the code of T34 was moving northwest and merged with ffj tag. We have had many problems with beacon tags. When aircraft landing and their tags jumping 4-6 mi usually 4 southwest and their mode C altitude of 200-600 ft while the aircraft is really on the runway. The collision avoidance alarm will sound when another aircraft tag is in the area at a close altitude. Callback conversation with reporter revealed the following information: reporter stated the problem is getting worse and that the arrival tab list has started jumping around generally toward the center of the display. Reporter also stated that they are getting numerous low altitude alerts. In answer to analyst question, reporter stated they were an ARTS 2A facility and they recently had a national patch installed. Reporter alleges the supervisors are not always logging the tag/tab list problem except when the system is unusable. Reporter indicated the facility management is supportive to have the problem fixed and believes it has been elevated to the hub facility.

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Original NASA ASRS Text

Title: RPT OF A DEPARTING T34'S DATA TAG JUMPING TO AND MERGING WITH A MIL FFJ'S TAG. AND RPT OF A LNDG ACFT'S TAG APPEARING NW OF THE ARPT WITH MODE C READOUT WHEN THE ACFT IS ACTUALLY ON THE RWY.

Narrative: I WAS WORKING DEP, RADAR AT GULFPORT APCH GULFPORT, MS. A T34 DEPARTED RWY 14 HDG 270 DEGS. AT THE SAME TIME A MIL ACFT AT THE SAME ALT WAS INBOUND ON THE ILS FOR RWY 14, 6 MI NW. THE BEACON CODE AND MODE C ALT JUMPED 4 MI NW RIGHT IN FRONT OF THE FFJ. BUT THE ACFT WAS REALLY 7 MI W OF GPT, PLUS THE CODE OF T34 WAS MOVING NW AND MERGED WITH FFJ TAG. WE HAVE HAD MANY PROBS WITH BEACON TAGS. WHEN ACFT LNDG AND THEIR TAGS JUMPING 4-6 MI USUALLY 4 SW AND THEIR MODE C ALT OF 200-600 FT WHILE THE ACFT IS REALLY ON THE RWY. THE COLLISION AVOIDANCE ALARM WILL SOUND WHEN ANOTHER ACFT TAG IS IN THE AREA AT A CLOSE ALT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE PROB IS GETTING WORSE AND THAT THE ARR TAB LIST HAS STARTED JUMPING AROUND GENERALLY TOWARD THE CTR OF THE DISPLAY. RPTR ALSO STATED THAT THEY ARE GETTING NUMEROUS LOW ALT ALERTS. IN ANSWER TO ANALYST QUESTION, RPTR STATED THEY WERE AN ARTS 2A FACILITY AND THEY RECENTLY HAD A NATIONAL PATCH INSTALLED. RPTR ALLEGES THE SUPVRS ARE NOT ALWAYS LOGGING THE TAG/TAB LIST PROB EXCEPT WHEN THE SYS IS UNUSABLE. RPTR INDICATED THE FACILITY MGMNT IS SUPPORTIVE TO HAVE THE PROB FIXED AND BELIEVES IT HAS BEEN ELEVATED TO THE HUB FACILITY.

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.