Narrative:

Aircraft X and aircraft Y were wbound on the worth 4 departure on the same radial. I was stepping aircraft X up in his climb due to air carrier Z also climbing wbound on the same departure and radial. I had approved a request from approach to stack air carrier Z and aircraft X with air carrier Z on top. At one point; I had issued aircraft X FL200 and entered that altitude as a temporary altitude in the data block. Later; after air carrier Z was level at FL230; I climbed aircraft X to FL220. At the time I was not receiving mode C altitude on aircraft X because of the closeness of the targets of aircraft X and air carrier Z. I consequently issued FL200 to aircraft Y; thinking aircraft X was out of FL200 for FL220. After issuing FL200 to aircraft Y; another air carrier west checked on frequency with a speed assignment which I had to clarify with the pilot. This took my attention away from aircraft X and aircraft Y. There were approximately 3 radar hits after I issued the aircraft Y FL200; that I might have realized the problem; but my attention was on dealing with air carrier west that had just checked on frequency. There are several contributing factors which I would like to bring forward: 1) departures from the dfw terminal area going to austin/san antonio/houston; were being rerouted out the west departure gate due to WX. This resulted in some additional issues: a) added complexity to the sector; B) pilot requests for shortcuts (more xmissions); C) some aircraft departed with the wrong routing and had to be issued correct routing; D) heavy volume on that particular departure radial resulting in dfw approach requesting to stack departures more than usual. 2) aircraft Y flight plan was incorrectly input into the system identing the flight as a T37 instead of a T38. These 2 aircraft have quite different flight characteristics. 3) with flts to aus/sat/iah being swapped out the west gate; there was no additional spacing placed on the departure route; even though this situation increases complexity as noted above.

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Original NASA ASRS Text

Title: ZFW CTLR EXPERIENCED OPERROR AT 17500 FT WHEN MODE ALT INFO WAS BLOCKED BECAUSE OF THE CLOSE PROX OF THE DATA BLOCKS.

Narrative: ACFT X AND ACFT Y WERE WBOUND ON THE WORTH 4 DEP ON THE SAME RADIAL. I WAS STEPPING ACFT X UP IN HIS CLB DUE TO ACR Z ALSO CLBING WBOUND ON THE SAME DEP AND RADIAL. I HAD APPROVED A REQUEST FROM APCH TO STACK ACR Z AND ACFT X WITH ACR Z ON TOP. AT ONE POINT; I HAD ISSUED ACFT X FL200 AND ENTERED THAT ALT AS A TEMPORARY ALT IN THE DATA BLOCK. LATER; AFTER ACR Z WAS LEVEL AT FL230; I CLBED ACFT X TO FL220. AT THE TIME I WAS NOT RECEIVING MODE C ALT ON ACFT X BECAUSE OF THE CLOSENESS OF THE TARGETS OF ACFT X AND ACR Z. I CONSEQUENTLY ISSUED FL200 TO ACFT Y; THINKING ACFT X WAS OUT OF FL200 FOR FL220. AFTER ISSUING FL200 TO ACFT Y; ANOTHER ACR W CHKED ON FREQ WITH A SPD ASSIGNMENT WHICH I HAD TO CLARIFY WITH THE PLT. THIS TOOK MY ATTN AWAY FROM ACFT X AND ACFT Y. THERE WERE APPROX 3 RADAR HITS AFTER I ISSUED THE ACFT Y FL200; THAT I MIGHT HAVE REALIZED THE PROB; BUT MY ATTN WAS ON DEALING WITH ACR W THAT HAD JUST CHKED ON FREQ. THERE ARE SEVERAL CONTRIBUTING FACTORS WHICH I WOULD LIKE TO BRING FORWARD: 1) DEPS FROM THE DFW TERMINAL AREA GOING TO AUSTIN/SAN ANTONIO/HOUSTON; WERE BEING REROUTED OUT THE W DEP GATE DUE TO WX. THIS RESULTED IN SOME ADDITIONAL ISSUES: A) ADDED COMPLEXITY TO THE SECTOR; B) PLT REQUESTS FOR SHORTCUTS (MORE XMISSIONS); C) SOME ACFT DEPARTED WITH THE WRONG ROUTING AND HAD TO BE ISSUED CORRECT ROUTING; D) HVY VOLUME ON THAT PARTICULAR DEP RADIAL RESULTING IN DFW APCH REQUESTING TO STACK DEPS MORE THAN USUAL. 2) ACFT Y FLT PLAN WAS INCORRECTLY INPUT INTO THE SYS IDENTING THE FLT AS A T37 INSTEAD OF A T38. THESE 2 ACFT HAVE QUITE DIFFERENT FLT CHARACTERISTICS. 3) WITH FLTS TO AUS/SAT/IAH BEING SWAPPED OUT THE W GATE; THERE WAS NO ADDITIONAL SPACING PLACED ON THE DEP RTE; EVEN THOUGH THIS SIT INCREASES COMPLEXITY AS NOTED ABOVE.

Data retrieved from NASA's ASRS site as of January 2009 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.