Narrative:

Morning of occurrence the facility primary radar was OTS for maintenance. I was working with a backup system that provides data, ie, altitude readouts every 12 seconds, when normally I receive data every 3-4 seconds. #1 aircraft was a B737 departing airport, heading swbound climbing to 8000 ft on frequency. #2 aircraft was handed off to me at 12000 ft descending to 9000 ft ssebound, off frequency. This aircraft was not at the correct altitude or position according to our LOA we have with other facilities. I was not sure exactly what previous controller heading was given to second aircraft. It appears to be ssebound. My plan was to pass to the north of descending aircraft. I turned aircraft #1 wbound and issued traffic. On first call from aircraft #2 I issued descent clearance with a restr to descend to 7000 ft, leaving 8000 ft, turn left heading 100 degrees. Both aircraft were about 15 mi apart at this time. After observing this plan was not working, I turned aircraft #1 40 degrees to the north and stopped descent of aircraft #2 and instructed aircraft #2 to climb back up to 9000 ft. At this time aircraft were about 5 mi apart. My data block then showed #2 aircraft at 8400 ft. I instructed aircraft #2 to expedite climb to which he replied level of 9000 ft. Aircraft #2 also reported #1 in sight. Due to the fact that I was unsure of heading issued by previous controller and that I was unfamiliar with the backup system, I might have lost needed separation. During use of backup system our standard separation is increased by 2 more mi per aircraft. No evasive action was taken by either aircraft. Suggestion on preventing occurrence: do radar maintenance during off periods. Get a descent backup system.

Related reports:

Google
 

Original NASA ASRS Text

Title: TRACON CTLR WORKING COMBINED APCH AND DEP CTL POS DSNDED A CPR JET THROUGH THE ALT OF AN ACR B737 WITH LTSS. TRACON WAS USING CENRAP AT THE TIME AS THE ASR WAS OTS FOR MAINT.

Narrative: MORNING OF OCCURRENCE THE FACILITY PRIMARY RADAR WAS OTS FOR MAINT. I WAS WORKING WITH A BACKUP SYS THAT PROVIDES DATA, IE, ALT READOUTS EVERY 12 SECONDS, WHEN NORMALLY I RECEIVE DATA EVERY 3-4 SECONDS. #1 ACFT WAS A B737 DEPARTING ARPT, HDG SWBOUND CLBING TO 8000 FT ON FREQ. #2 ACFT WAS HANDED OFF TO ME AT 12000 FT DSNDING TO 9000 FT SSEBOUND, OFF FREQ. THIS ACFT WAS NOT AT THE CORRECT ALT OR POS ACCORDING TO OUR LOA WE HAVE WITH OTHER FACILITIES. I WAS NOT SURE EXACTLY WHAT PREVIOUS CTLR HDG WAS GIVEN TO SECOND ACFT. IT APPEARS TO BE SSEBOUND. MY PLAN WAS TO PASS TO THE N OF DSNDING ACFT. I TURNED ACFT #1 WBOUND AND ISSUED TFC. ON FIRST CALL FROM ACFT #2 I ISSUED DSCNT CLRNC WITH A RESTR TO DSND TO 7000 FT, LEAVING 8000 FT, TURN L HDG 100 DEGS. BOTH ACFT WERE ABOUT 15 MI APART AT THIS TIME. AFTER OBSERVING THIS PLAN WAS NOT WORKING, I TURNED ACFT #1 40 DEGS TO THE N AND STOPPED DSCNT OF ACFT #2 AND INSTRUCTED ACFT #2 TO CLB BACK UP TO 9000 FT. AT THIS TIME ACFT WERE ABOUT 5 MI APART. MY DATA BLOCK THEN SHOWED #2 ACFT AT 8400 FT. I INSTRUCTED ACFT #2 TO EXPEDITE CLB TO WHICH HE REPLIED LEVEL OF 9000 FT. ACFT #2 ALSO RPTED #1 IN SIGHT. DUE TO THE FACT THAT I WAS UNSURE OF HDG ISSUED BY PREVIOUS CTLR AND THAT I WAS UNFAMILIAR WITH THE BACKUP SYS, I MIGHT HAVE LOST NEEDED SEPARATION. DURING USE OF BACKUP SYS OUR STANDARD SEPARATION IS INCREASED BY 2 MORE MI PER ACFT. NO EVASIVE ACTION WAS TAKEN BY EITHER ACFT. SUGGESTION ON PREVENTING OCCURRENCE: DO RADAR MAINT DURING OFF PERIODS. GET A DSCNT BACKUP SYS.

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.