Narrative:

Almost immediately after assuming the LAW1 position; I heard final monitor 3 cancel the approach clearance for a MD82 who was following a B777 heavy on the ILS 18R approach. Because this was my first cognizant recollection of the MD82's presence on frequency; I did not apply the 'J-ring' to ascertain distance behind the B777 heavy; but rather commenced to coordinating the go-around heading and hand off with DR1. The MD82 was assigned a heading of 185 and an altitude of 3;000 by LW1 and this was coordinated with DR1. Within that same time frame; an E145 was told to 'line up and wait' on runway 18L pending appropriate separation being established with the MD82 on the go-around. The E145 was filed via the akuna RNAV SID which would require what is known as an 'inside track' departure from dfw's west complex after being released by the east tower because an akuna departure would ideally depart the east complex of dfw. Separation requirements between a preceding conventional departure followed by a RNAV 'inside track' departure is 5 miles; and this would have been the appropriate separation between the MD82 and the E145; but the LW1 controller issued takeoff clearance to the E145 when the MD82 was only 3 miles ahead. This created a 'cut-off' scenario once the E145 was airborne and flying the RNAV departure and I did observe this on the racd with closest proximity being approximately 2 1/2 miles and approximately 1;000 ft; although I did not verify this using racd equipment. Recommendation; first; regarding the in-trail scenario between the B777 heavy and the succeeding the MD82; 'immediate' vigilance on my part as an assistant might have helped pre-plan the go-around better and be certain as to what separation actually existed. Second; because we were being question by the flm with regard to distance and actual location of the MD82 when their approach clearance was canceled; in an effort to determine whose responsibility; tower or D10 TRACON; it had been for separation during that incident; I was hesitant to draw further attention to the local west position by reminding LW1 that the appropriate separation between the MD82 on the go-around and the succeeding the E145 was five miles; not three miles. But; as I saw the 'cut-off' scenario develop in a more-pronounced-than-usual way; I felt remorse that I had not clued the LW1 controller in regarding his mistake in calculating separation requirements. In the future; I will a.) maintain constant awareness and vigilance upon assuming position to eliminate the possibility of 'surprises'; and B.) will absolutely speak up whenever I see that incorrect separation minima has been applied.

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Original NASA ASRS Text

Title: DFW Controller described a loss of separation event when the Local Controller failed to provide adequate separation between a go around and a subsequent departure; resulting in 'cut-off' scenario.

Narrative: Almost immediately after assuming the LAW1 position; I heard Final Monitor 3 cancel the approach clearance for a MD82 who was following a B777 Heavy on the ILS 18R approach. Because this was my first cognizant recollection of the MD82's presence on frequency; I did not apply the 'J-Ring' to ascertain distance behind the B777 Heavy; but rather commenced to coordinating the go-around heading and hand off with DR1. The MD82 was assigned a heading of 185 and an altitude of 3;000 by LW1 and this was coordinated with DR1. Within that same time frame; an E145 was told to 'Line Up and Wait' on Runway 18L pending appropriate separation being established with the MD82 on the go-around. The E145 was filed via the AKUNA RNAV SID which would require what is known as an 'inside track' departure from DFW's West Complex after being released by the East Tower because an AKUNA departure would ideally depart the east complex of DFW. Separation requirements between a preceding conventional departure followed by a RNAV 'inside track' departure is 5 miles; and this would have been the appropriate separation between the MD82 and the E145; but the LW1 Controller issued takeoff clearance to the E145 when the MD82 was only 3 miles ahead. This created a 'cut-off' scenario once the E145 was airborne and flying the RNAV departure and I did observe this on the RACD with closest proximity being approximately 2 1/2 miles and approximately 1;000 FT; although I did not verify this using RACD equipment. Recommendation; first; regarding the in-trail scenario between the B777 Heavy and the succeeding the MD82; 'immediate' vigilance on my part as an Assistant might have helped pre-plan the go-around better and be certain as to what separation actually existed. Second; because we were being question by the FLM with regard to distance and actual location of the MD82 when their approach clearance was canceled; in an effort to determine whose responsibility; Tower or D10 TRACON; it had been for separation during that incident; I was hesitant to draw further attention to the Local West position by reminding LW1 that the appropriate separation between the MD82 on the go-around and the succeeding the E145 was five miles; not three miles. But; as I saw the 'cut-off' scenario develop in a more-pronounced-than-usual way; I felt remorse that I had not clued the LW1 Controller in regarding his mistake in calculating separation requirements. In the future; I will A.) Maintain constant awareness and vigilance upon assuming position to eliminate the possibility of 'surprises'; and B.) Will absolutely speak up whenever I see that incorrect separation minima has been applied.

Data retrieved from NASA's ASRS site as of April 2012 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.