Narrative:

The dfw north flow; west ATCT; simultaneous independent ILS; aircraft in sight at 2.5 mile final. D10 is responsible for longitudinal separation from the FAF to the runway threshold. I was working ground 1 but observed this operation and thought it was unsafe. Furthermore; it reveals one situation; among several; where flms (front line managers) are telling cpcs (certified professional controllers) directly or indirectly that a proximity event (pe) is okay. The flms are suggesting that dfw cpcs don't break aircraft out at minimum separation; but go down to pe separation. This is confusing the cpcs and causing them to question their own judgment. A MD80 was barely 4 miles in trail of a B757; on runway 36L final approach course. Local west was utilizing j-rings. Separation was decreasing because the MD80 was 30-40 KTS faster than the B757. While the MD80 was outside the FAF; D10 final monitor position didn't issue instructions to slow the MD80 and dfw local control cannot issue instructions to slow in approach controls airspace. When the MD80 was in the vicinity of the FAF; dfw flm ordered dfw local west and local assist west to not send the MD80 around. At this point; the MD80 was exactly 4 miles in trail and spacing was decreasing. Local west; confused about what to do now; attempted to ask the MD80 if he had the B757 in sight to possibly clear the MD80 for a visual approach; but the MD80 was IMC. Now; separation has decreased to approximately 3.8 miles. D10 final monitor; who monitors local west and has override capabilities; breaks out the MD80 inside dfw's airspace seeing that separation no longer existed. I later asked the flm why he ordered local west to have the MD80 continue approach. The flm said because the MD80 was 1 mile outside our airspace and separation had not been lost yet. I and everybody else in the tower disagree. The MD80 was very close to the FAF (within a mile) and separation was about to be lost with the 30-4 KT overtake. In other situations of decreasing separation; flms have been heard to suggest stretching or enlargement of the racd (remote ARTS color display) display so the controller can 'hone in' on the exact amount of separation. This is a dangerous suggestion. First of all; the local controller is responsible for monitoring airspace beyond the decreasing separation situation. Stretching out the racd picture eliminates the other portions of airspace that local control has a duty to monitor. Secondly; this causes the local controller to stare at the racd when their attention should be divided between scanning runways; taxiways; aircraft; and airspace for unsafe situations.

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Original NASA ASRS Text

Title: DFW Controller witnessed a go-around event when the local controller was directed by a supervisor to not to issue a go-around even though wake separation was questionable.

Narrative: The DFW north flow; west ATCT; Simultaneous Independent ILS; aircraft in sight at 2.5 mile final. D10 is responsible for longitudinal separation from the FAF to the runway threshold. I was working Ground 1 but observed this operation and thought it was unsafe. Furthermore; it reveals one situation; among several; where FLMs (Front Line Managers) are telling CPCs (Certified Professional Controllers) directly or indirectly that a proximity event (PE) is okay. The FLMs are suggesting that DFW CPCs don't break aircraft out at minimum separation; but go down to PE separation. This is confusing the CPCs and causing them to question their own judgment. A MD80 was barely 4 miles in trail of a B757; on Runway 36L final approach course. Local West was utilizing J-rings. Separation was decreasing because the MD80 was 30-40 KTS faster than the B757. While the MD80 was outside the FAF; D10 final monitor position didn't issue instructions to slow the MD80 and DFW Local Control cannot issue instructions to slow in approach controls airspace. When the MD80 was in the vicinity of the FAF; DFW FLM ordered DFW Local West and Local Assist West to not send the MD80 around. At this point; the MD80 was exactly 4 miles in trail and spacing was decreasing. Local West; confused about what to do now; attempted to ask the MD80 if he had the B757 in sight to possibly clear the MD80 for a visual approach; but the MD80 was IMC. Now; separation has decreased to approximately 3.8 miles. D10 final monitor; who monitors Local West and has override capabilities; breaks out the MD80 inside DFW's airspace seeing that separation no longer existed. I later asked the FLM why he ordered Local West to have the MD80 continue approach. The FLM said because the MD80 was 1 mile outside our airspace and separation had not been lost yet. I and everybody else in the Tower disagree. The MD80 was very close to the FAF (within a mile) and separation was about to be lost with the 30-4 KT overtake. In other situations of decreasing separation; FLMs have been heard to suggest stretching or enlargement of the RACD (Remote ARTS Color Display) display so the controller can 'hone in' on the exact amount of separation. This is a dangerous suggestion. First of all; the Local Controller is responsible for monitoring airspace beyond the decreasing separation situation. Stretching out the RACD picture eliminates the other portions of airspace that Local Control has a duty to monitor. Secondly; this causes the Local Controller to stare at the RACD when their attention should be divided between scanning runways; taxiways; aircraft; and airspace for unsafe situations.

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.