Narrative:

Weather impacted dfw with deicing procedures causing aircraft de-iced to depart the runway closest to their deicing station. Aircraft X eastbound departure deiced in the hold pad for runway 36R and aircraft Y an eastbound departure deiced in the hold pad for runway 35L. The weather was IFR and did not allow for visual separation. I was training a new trainee on local assist east and coordinated a release for a soldo departure for aircraft X with local east (LE1) controller. That release was given and in the interim a request was progress for an eastbound prop aircraft. While [I was] in the process of explaining to my trainee the call for release on an east prop that had been deiced and having the trainee coordinate with the satellite controller LE1 issue a takeoff clearance to aircraft Y. I had completed discussing with my trainee that although he coordinated with dallas north (dn) the dallas south (ds) controller answered the land line which confused my trainee at first since he was pushing the dn line. Shortly afterward I re-engaged to what LE1 was doing and regaining the picture out the window. I immediately noticed that aircraft X was tagged and showed soldo as his departure fix. I yelled to LE1 that he had a release with LW1 and told him to take corrective action as well as have my trainee coordinate with DR1. Unfortunately; LE1 had already switched aircraft Y. I started to coordinate with DR1 and listened to hear them talking to aircraft X. Because aircraft X was on a soldo departure his flight path would cross through the flight path of aircraft Y who was ahead of aircraft X. The expectation that after coordination was effected and acknowledged; the LE1 controller simply forgot that he had to protect for a departure off the west side of the airport. Dfw was in a north flow configuration with aircraft deicing. Training on LAE1; LW1; DR1; and newly certified controller on LAW1. The instruction I was providing to my trainee was based on his inexperience so I turned my attention to explaining how the deicing procedures impact him and how getting timely releases for prop departures as well as releases for jet departures. It should be considered that the requirement for tower to request releases for prop departures is at times a distraction. In years past at dfw we worked ten times the amount of prop departures with automatic releases; but since RNAV; the requirement was written into our local procedures. Under normal weather conditions all eastbound jets would depart the east side of dfw to avoid crossing flight paths. This rule was implemented to avoid conflict. With RNAV engaged at the runway any corrective action must occur prior to the aircraft turning. It is my belief that during deicing and perhaps during CAT11 and III operations; dfw tower have all jet departures fly a radar vector to maintain lateral spacing. That was the SOP in the past and a good operating practice since it afforded the tower controller the ability to ensure that no conflicts existed before turning. If TRACON can impose radar vectors for weather due to course conflict away from the airport then tower should be able to use radar vectors as well. It is common sense to do the safest operation. RNAV is a good departure procedure but it has its drawbacks. The tower controller is discouraged from taking a jet off RNAV. I would like to see dfw use radar vectors when in the controllers opinion it would provide for a safe operation with more control options for the air traffic controller. And finally; I feel it is important to not allow oneself to become disengaged from the operation no matter the training; weather; or confidence level.

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Original NASA ASRS Text

Title: DFW controller providing OJT on a Local Assist position described a loss of separation event; reportedly caused by unusual de-icing procedures and departure runway requests; reporter claiming RADAR vectors would be a better procedure in lieu of matching RNAV procedure with changing departure runway requests.

Narrative: Weather impacted DFW with deicing procedures causing aircraft de-iced to depart the runway closest to their deicing station. Aircraft X eastbound departure deiced in the hold pad for Runway 36R and Aircraft Y an eastbound departure deiced in the hold pad for Runway 35L. The weather was IFR and did not allow for visual separation. I was training a new trainee on Local Assist East and coordinated a release for a SOLDO departure for Aircraft X with Local East (LE1) Controller. That release was given and in the interim a request was progress for an eastbound prop aircraft. While [I was] in the process of explaining to my trainee the call for release on an east prop that had been deiced and having the trainee coordinate with the Satellite Controller LE1 issue a takeoff clearance to Aircraft Y. I had completed discussing with my trainee that although he coordinated with Dallas North (DN) the Dallas South (DS) Controller answered the land line which confused my trainee at first since he was pushing the DN line. Shortly afterward I re-engaged to what LE1 was doing and regaining the picture out the window. I immediately noticed that Aircraft X was tagged and showed SOLDO as his departure fix. I yelled to LE1 that he had a release with LW1 and told him to take corrective action as well as have my trainee coordinate with DR1. Unfortunately; LE1 had already switched Aircraft Y. I started to coordinate with DR1 and listened to hear them talking to Aircraft X. Because Aircraft X was on a SOLDO departure his flight path would cross through the flight path of Aircraft Y who was ahead of Aircraft X. The expectation that after coordination was effected and acknowledged; the LE1 controller simply forgot that he had to protect for a departure off the West side of the airport. DFW was in a North Flow configuration with aircraft deicing. Training on LAE1; LW1; DR1; and newly certified controller on LAW1. The instruction I was providing to my trainee was based on his inexperience so I turned my attention to explaining how the deicing procedures impact him and how getting timely releases for prop departures as well as releases for jet departures. It should be considered that the requirement for Tower to request releases for prop departures is at times a distraction. In years past at DFW we worked ten times the amount of prop departures with automatic releases; but since RNAV; the requirement was written into our local procedures. Under normal weather conditions all eastbound jets would depart the east side of DFW to avoid crossing flight paths. This rule was implemented to avoid conflict. With RNAV engaged at the runway any corrective action must occur prior to the aircraft turning. It is my belief that during deicing and perhaps during CAT11 and III operations; DFW Tower have all jet departures fly a radar vector to maintain lateral spacing. That was the SOP in the past and a good operating practice since it afforded the tower controller the ability to ensure that no conflicts existed before turning. If TRACON can impose RADAR vectors for weather due to course conflict away from the airport then Tower should be able to use RADAR vectors as well. It is common sense to do the safest operation. RNAV is a good departure procedure but it has its drawbacks. The Tower Controller is discouraged from taking a jet off RNAV. I would like to see DFW use radar vectors when in the controllers opinion it would provide for a safe operation with more control options for the Air Traffic Controller. And finally; I feel it is important to not allow oneself to become disengaged from the operation no matter the training; weather; or confidence level.

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.