Commercial Fixed Wing
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 7
Situational Awareness; Communication Breakdown; Distraction
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Executed Go Around / Missed Approach
Procedure; Human Factors
I had cleared Aircraft X to land runway 36L and advised them that traffic would be holding in position.  I told Aircraft Y LUAW [Line Up And Wait] on runway 36L and advised them about traffic on final for the same runway.  I then began discussing something with my assist controller and forgot about the aircraft on the runway.  Aircraft X asked if I was going to make this work; I then sent Aircraft X around.  There was no reason to have assist open at the time of the event; traffic was very slow.  DFW has a requirement to have assist open even when not needed.  Many times; like this one; local and their assist get distracted in conversation.  The conversation we were having was concerning the operation; but was not important.Close the assist position at DFW when not needed.
DFW Controller loads the runway while an aircraft is on final to same runway. Controller gets distracted by discussion with Local Assist. Pilot of landing aircraft asks Local if this is going to work and is sent around. Controller blames the assist for the distraction and complains that Local Assist should not have been open.