Narrative:

I was being relieved by a developmental with his ojti monitoring the relief briefing. I had already cleared air carrier X heavy to land on runway 36L and was awaiting air carrier Y to report on frequency. Due to a recent local requirement for a red 'rid' (runway incursion device--basically a red strip holder) to be placed in the local controller's bay by the ground controller when a crossing of the departure runway is approved; ground control had just requested; and I had approved; a crossing of the departure runway (runway 36R) with a maintenance aircraft; and subsequently put a B757 into position and hold on runway 36R with the B757's strip placed upside down as an additional reminder to myself that the runway was occupied. When the developmental plugged in to receive the relief briefing he; unnoticed by me; placed the B757 (tiph; RY36R) 'perpendicular' to the strip of the departure which was airborne but still on my frequency. When I looked down at my strip bay to switch air carrier Y to the departure sector; I noticed only one strip holder in my bay; and the strip itself was 'offset' indicating that the aircraft was cleared for takeoff. I became immediately concerned because ground control was crossing the departure runway and I recalled only having put the B757 into position and hold! I then noticed the perpendicular 'turned over' strip holder beside the red 'rid'; turned the strip holder over; and observed that it was indeed the strip holder for the B757 who was tiph on runway 36R. I asked the developmental; 'did you put this strip holder here?' to which he replied in the affirmative. While this confusion was going on regarding the whereabouts of the B757 strip; and whether or not I might have inadvertently cleared him for takeoff; (which I had not); air carrier Y had joined final behind air carrier X heavy but had not checked in on frequency. In the midst of the aforementioned confusion; I had also not noticed the overtaking speed of air carrier Y; and as I completed the briefing; I noted that air carrier Y was not yet on frequency nor had air carrier Y been cleared to land. It was then that the relieving controllers (deviation & ojti; and I) observed air carrier Y in a westbound turn which had obviously been assigned by the arrival controller; as air carrier Y was not on my frequency. The incoming ojti queried about the spacing of air carrier Y behind air carrier X heavy; to which I was unable to respond in certainty due to my confusion over the developmental displacing strips in my strip bay prior to/during the relief briefing. Air carrier Y was vectored back to the runway 36L final approach course and was on short final when I departed the tower cab. Because of the fairly tight physical confines of the LW1 position when LAW1 is staffed and a training team is incoming for the relief briefing for either position; a prime opportunity for inappropriate interference; distraction; and confusion exists. First of all; an incoming developmental should never mess around with the outgoing controller's strip bay; strips; notepad; or equipment; this again presents a prime opportunity for mistakes to occur. In terms of my responsibility; multi-tasking is critical in these easily confusing situations and regardless of where the outbound B757's strip was; it was still my responsibility to monitor spacing on final behind air carrier X heavy; which I do not feel that I performed adequately. In the future; I will brief more slowly and thoroughly while pausing to accomplish all requirements of the position for which I am responsible; including monitoring spacing on final! This was an embarrassing and unnecessary surprise at the end of my session. Granted; I believe that the incoming developmental 'helped' me down the path to a possible oversight and mistake; ultimately the responsibilities for the position were mine and I will more conscientiously complete them in the future.

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Original NASA ASRS Text

Title: A DFW Controller described a very confused position relief event when a Developmental; who was assuming the position; altered strip bay causing confusion that resulted eventually in a separation situation on final.

Narrative: I was being relieved by a Developmental with his OJTI monitoring the relief briefing. I had already cleared Air Carrier X Heavy to land on Runway 36L and was awaiting Air Carrier Y to report on frequency. Due to a recent local requirement for a red 'RID' (Runway Incursion Device--basically a red strip holder) to be placed in the Local Controller's bay by the Ground Controller when a crossing of the departure runway is approved; Ground Control had just requested; and I had approved; a crossing of the departure runway (Runway 36R) with a maintenance aircraft; and subsequently put a B757 into position and hold on Runway 36R with the B757's strip placed upside down as an additional reminder to myself that the runway was occupied. When the Developmental plugged in to receive the relief briefing he; unnoticed by me; placed the B757 (TIPH; RY36R) 'perpendicular' to the strip of the departure which was airborne but still on my frequency. When I looked down at my strip bay to switch Air Carrier Y to the departure sector; I noticed only ONE strip holder in my bay; and the strip itself was 'offset' indicating that the aircraft was cleared for takeoff. I became immediately concerned because Ground Control was crossing the departure runway and I recalled ONLY having put the B757 into position and hold! I then noticed the perpendicular 'turned over' strip holder beside the red 'RID'; turned the strip holder over; and observed that it was indeed the strip holder for the B757 who was TIPH on Runway 36R. I asked the Developmental; 'Did you put this strip holder here?' to which he replied in the affirmative. While this confusion was going on regarding the whereabouts of the B757 strip; and whether or not I might have inadvertently cleared him for takeoff; (which I had NOT); Air Carrier Y had joined final behind Air Carrier X Heavy but had not checked in on frequency. In the midst of the aforementioned confusion; I had also not noticed the overtaking speed of Air Carrier Y; and as I completed the briefing; I noted that Air Carrier Y was not yet on frequency nor had Air Carrier Y been cleared to land. It was then that the relieving controllers (DEV & OJTI; and I) observed Air Carrier Y in a westbound turn which had obviously been assigned by the Arrival Controller; as Air Carrier Y was not on my frequency. The incoming OJTI queried about the spacing of Air Carrier Y behind Air Carrier X Heavy; to which I was unable to respond in certainty due to my confusion over the Developmental displacing strips in my strip bay prior to/during the relief briefing. Air Carrier Y was vectored back to the Runway 36L final approach course and was on short final when I departed the tower cab. Because of the fairly tight physical confines of the LW1 position when LAW1 is staffed and a training team is incoming for the relief briefing for either position; a prime opportunity for inappropriate interference; distraction; and confusion exists. First of all; an incoming Developmental should never mess around with the outgoing Controller's strip bay; strips; notepad; or equipment; this again presents a prime opportunity for mistakes to occur. In terms of my responsibility; multi-tasking is critical in these easily confusing situations and regardless of where the outbound B757's strip was; it was still my responsibility to monitor spacing on final behind Air Carrier X Heavy; which I do not feel that I performed adequately. In the future; I will brief more slowly and thoroughly while pausing to accomplish all requirements of the position for which I am responsible; including monitoring spacing on final! This was an embarrassing and unnecessary surprise at the end of my session. Granted; I believe that the incoming Developmental 'helped' me down the path to a possible oversight and mistake; ultimately the responsibilities for the position were mine and I will more conscientiously complete them in the future.

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.