Narrative:

Dfw approach control is set up on the cornerpost system. Departure aircraft are climbed to an initial altitude below arrival aircraft. Once the departures are clear of traffic and/or the arrival corridor, they are climbed to 17000'. Many time the departure aircraft reports on ftw ARTCC frequency still only cleared to an interim altitude. Because of human error (both controller and pilot), this can be a dangerous situation. Not every incorrect altitude is coordinated or noticed. The LOA between dfw and ZFW states that 'all turbojet aircraft (departures) shall be climbing to 17000' unless otherwise specified or coordinated.' air carrier X took another departure aircraft frequency change. Because no other altitude had been coordinated, it was expected that air carrier X would be climbing to 17000'. Air carrier X was climbed to FL230. Shortly thereafter air carrier X advised ZFW ARTCC that they just had a near miss with a company widebody transport (an arrival aircraft). Because of current problems (as previously described), the potential for this same situation to recur is extremely high. Following are some suggestions to assist in the prevention of the aforementioned scenario (however, not all of these suggestions are practical to both the ARTCC and the approach control): 1) do not change aircraft frequency prior to passing through 11000'. 2) do not initiate handoff until aircraft is clear of traffic and/or arrival corridor. These 2 suggests are very simple. Aircraft reporting on frequency doing anything other than above would alert ATC's to potential problem. Unfortunately, at the present time and present airspace confign between ZFW and dfw these suggestions may not be practical. Supplemental information from acn 160598: I turned the aircraft to a 270 degree heading, intercepted the 079 degree right and leveled off at 10000'. Regional departure control issued a frequency change of 127.0 to contact ZFW. The first officer read the frequency back to the departure controller, paused for a few seconds and then contacted ZFW on 127.0. The center controller seemed surprised that we were on her frequency. She verified our call sign and the first officer confirmed it with her. She then cleared us to climb to FL230. The first officer read the clearance back to her. I started the climb, and at about 10500' we saw a widebody transport at our 12 O'clock position. I leveled our aircraft at 10700' and started to descend. The widebody transport was on the acton arrival at 11000' and approaching creek intersection. My first officer called center and told her that we just had a 'near midair with a widebody transport.' after about 1 15 second period of confusion, she told us to return to departure control on 124.25. The first officer called departure control. The controller said that we accepted another aircraft's frequency change and he told us to maintain 10000'. The other aircraft had a similar sounding call sign. I believe several factors contributed to this event: frequency congestion, flight crew failing to hear the correct call sign, departure controller failure to catch our readback of an incorrect call sign, and ZFW issuing a climb with conflicting traffic.

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Original NASA ASRS Text

Title: A DEP ACR ACCEPTED CLIMB CLRNC FOR ANOTHER ACFT WITH SIMILAR CALL SIGN RESULTING IN LESS THAN STANDARD SEPARATION WITH AN ARRIVING ACR.

Narrative: DFW APCH CTL IS SET UP ON THE CORNERPOST SYS. DEP ACFT ARE CLBED TO AN INITIAL ALT BELOW ARR ACFT. ONCE THE DEPS ARE CLR OF TFC AND/OR THE ARR CORRIDOR, THEY ARE CLBED TO 17000'. MANY TIME THE DEP ACFT RPTS ON FTW ARTCC FREQ STILL ONLY CLRED TO AN INTERIM ALT. BECAUSE OF HUMAN ERROR (BOTH CTLR AND PLT), THIS CAN BE A DANGEROUS SITUATION. NOT EVERY INCORRECT ALT IS COORDINATED OR NOTICED. THE LOA BTWN DFW AND ZFW STATES THAT 'ALL TURBOJET ACFT (DEPS) SHALL BE CLBING TO 17000' UNLESS OTHERWISE SPECIFIED OR COORDINATED.' ACR X TOOK ANOTHER DEP ACFT FREQ CHANGE. BECAUSE NO OTHER ALT HAD BEEN COORDINATED, IT WAS EXPECTED THAT ACR X WOULD BE CLBING TO 17000'. ACR X WAS CLBED TO FL230. SHORTLY THEREAFTER ACR X ADVISED ZFW ARTCC THAT THEY JUST HAD A NEAR MISS WITH A COMPANY WDB (AN ARR ACFT). BECAUSE OF CURRENT PROBS (AS PREVIOUSLY DESCRIBED), THE POTENTIAL FOR THIS SAME SITUATION TO RECUR IS EXTREMELY HIGH. FOLLOWING ARE SOME SUGGESTIONS TO ASSIST IN THE PREVENTION OF THE AFOREMENTIONED SCENARIO (HOWEVER, NOT ALL OF THESE SUGGESTIONS ARE PRACTICAL TO BOTH THE ARTCC AND THE APCH CTL): 1) DO NOT CHANGE ACFT FREQ PRIOR TO PASSING THROUGH 11000'. 2) DO NOT INITIATE HDOF UNTIL ACFT IS CLR OF TFC AND/OR ARR CORRIDOR. THESE 2 SUGGESTS ARE VERY SIMPLE. ACFT RPTING ON FREQ DOING ANYTHING OTHER THAN ABOVE WOULD ALERT ATC'S TO POTENTIAL PROB. UNFORTUNATELY, AT THE PRESENT TIME AND PRESENT AIRSPACE CONFIGN BTWN ZFW AND DFW THESE SUGGESTIONS MAY NOT BE PRACTICAL. SUPPLEMENTAL INFO FROM ACN 160598: I TURNED THE ACFT TO A 270 DEG HDG, INTERCEPTED THE 079 DEG R AND LEVELED OFF AT 10000'. REGIONAL DEP CTL ISSUED A FREQ CHANGE OF 127.0 TO CONTACT ZFW. THE F/O READ THE FREQ BACK TO THE DEP CTLR, PAUSED FOR A FEW SECS AND THEN CONTACTED ZFW ON 127.0. THE CENTER CTLR SEEMED SURPRISED THAT WE WERE ON HER FREQ. SHE VERIFIED OUR CALL SIGN AND THE F/O CONFIRMED IT WITH HER. SHE THEN CLRED US TO CLB TO FL230. THE F/O READ THE CLRNC BACK TO HER. I STARTED THE CLB, AND AT ABOUT 10500' WE SAW A WDB AT OUR 12 O'CLOCK POS. I LEVELED OUR ACFT AT 10700' AND STARTED TO DSND. THE WDB WAS ON THE ACTON ARR AT 11000' AND APCHING CREEK INTXN. MY F/O CALLED CENTER AND TOLD HER THAT WE JUST HAD A 'NEAR MIDAIR WITH A WDB.' AFTER ABOUT 1 15 SEC PERIOD OF CONFUSION, SHE TOLD US TO RETURN TO DEP CTL ON 124.25. THE F/O CALLED DEP CTL. THE CTLR SAID THAT WE ACCEPTED ANOTHER ACFT'S FREQ CHANGE AND HE TOLD US TO MAINTAIN 10000'. THE OTHER ACFT HAD A SIMILAR SOUNDING CALL SIGN. I BELIEVE SEVERAL FACTORS CONTRIBUTED TO THIS EVENT: FREQ CONGESTION, FLT CREW FAILING TO HEAR THE CORRECT CALL SIGN, DEP CTLR FAILURE TO CATCH OUR READBACK OF AN INCORRECT CALL SIGN, AND ZFW ISSUING A CLB WITH CONFLICTING TFC.

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.