Narrative:

Among the numerous departures, small transport X departed on a tower assigned heading of 090 degrees climbing to 3000'. I radar idented small transport X and climbed small transport X to 5000', heading 090 degrees. Approximately 2 mins later mlt Y departed on tower assigned heading of 090 degrees, climbing to 3000'. Mlt Y had an overtake speed of 70-80 KTS on small transport X, closing rapidly. Small transport X was out of 3100' climbing. Mlt Y was out of at least 2000' and approximately 2.5 NM behind small transport X. I assumed tower had sep via visual sep rules, but as I queried mlt Y to verify he had small transport X in sight, mlt Y responded to my traffic advisory by stating, 'we're looking.' realizing he did not have small transport X in sight, my radar assistant coordinated with final to turn small transport X into their airspace. I turned small transport X to 130 degrees to establish course divergence sep. This incident was reported to supervisor personnel as I wanted an explanation from the tower. The tower controllers admitted fault, stating training as a factor. A trnee and instrument were working the local controller position. The ARTS playback tape showed less than 3 mi sep, but due to maintenance work being done on the ARTS equipment, no readout of mlt Y's altitude readout was available. I dropped the charges against the 2 local controllers as I could not recall the specific altitude of mlt Y. The 2 controllers have been counseled. To avoid this incident recurring, controllers have to be very aware of aircraft speeds and overtake capabilities.

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Original NASA ASRS Text

Title: ATX-SMT OVERTAKEN BY MLT WHILE BOTH WERE ON DEP VECTORS CLIMBING RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: AMONG THE NUMEROUS DEPS, SMT X DEPARTED ON A TWR ASSIGNED HDG OF 090 DEGS CLBING TO 3000'. I RADAR IDENTED SMT X AND CLBED SMT X TO 5000', HDG 090 DEGS. APPROX 2 MINS LATER MLT Y DEPARTED ON TWR ASSIGNED HDG OF 090 DEGS, CLBING TO 3000'. MLT Y HAD AN OVERTAKE SPD OF 70-80 KTS ON SMT X, CLOSING RAPIDLY. SMT X WAS OUT OF 3100' CLBING. MLT Y WAS OUT OF AT LEAST 2000' AND APPROX 2.5 NM BEHIND SMT X. I ASSUMED TWR HAD SEP VIA VISUAL SEP RULES, BUT AS I QUERIED MLT Y TO VERIFY HE HAD SMT X IN SIGHT, MLT Y RESPONDED TO MY TFC ADVISORY BY STATING, 'WE'RE LOOKING.' REALIZING HE DID NOT HAVE SMT X IN SIGHT, MY RADAR ASSISTANT COORDINATED WITH FINAL TO TURN SMT X INTO THEIR AIRSPACE. I TURNED SMT X TO 130 DEGS TO ESTABLISH COURSE DIVERGENCE SEP. THIS INCIDENT WAS RPTED TO SUPVR PERSONNEL AS I WANTED AN EXPLANATION FROM THE TWR. THE TWR CTLRS ADMITTED FAULT, STATING TRNING AS A FACTOR. A TRNEE AND INSTR WERE WORKING THE LCL CTLR POS. THE ARTS PLAYBACK TAPE SHOWED LESS THAN 3 MI SEP, BUT DUE TO MAINT WORK BEING DONE ON THE ARTS EQUIP, NO READOUT OF MLT Y'S ALT READOUT WAS AVAILABLE. I DROPPED THE CHARGES AGAINST THE 2 LCL CTLRS AS I COULD NOT RECALL THE SPECIFIC ALT OF MLT Y. THE 2 CTLRS HAVE BEEN COUNSELED. TO AVOID THIS INCIDENT RECURRING, CTLRS HAVE TO BE VERY AWARE OF ACFT SPDS AND OVERTAKE CAPABILITIES.

Data retrieved from NASA's ASRS site as of August 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.