Narrative:

An airport vehicle was conducting a field inspection with a FAA airports certification official on board and was located between the runways on taxiway echo. A helicopter (aircraft X) had just departed runway 20 and entered the crosswind for taxiway delta but had not received a clearance. A citation was inbound IFR from the northeast for runway 11L and a north american T-6 was a northwest departure from the airport. I was focused on issuing traffic to those two aircraft just prior to the airport vehicle's request to proceed to taxiway golf. I instructed the vehicle to cross runway 11R and proceed westbound via taxiway delta and to hold short of runway 11R abeam golf (taxiway golf located between the parallel runways). The controller in charge alerted me to aircraft X on downwind about to turn base. When aircraft X reported base for taxiway delta; I changed him to runway 11R and advised him to expect a couple patterns on runway 11R to allow for the airfield inspection. I had not realized aircraft X had passed beam taxiway echo; their downwind; when the airport vehicle had called for relocation to taxiway golf and thought I had time to keep the vehicle on taxiways to their requested location before aircraft X would reach their base. Recommendation; I had been issuing traffic to a citation inbound and a north american outbound just prior to this incident. I had taken the helicopter quite a ways out before turning their crosswind and had not relocated my strip to the delta taxiway header; indicating he was not yet in the pattern. I had thought the helicopter was further east on downwind when the airport vehicle requested reposition and issued those instructions. The controller in charge was aware of the helicopter position and prompted me to make my landing area reassignment to the helicopter promptly to avoid a conflict. I should have located the helicopter before issuing the instructions to the vehicle or issued the new landing instructions to the helicopter before issuing the instructions to the vehicle. A better scan of my strip area and pattern to correlate the strips with what is actually going on in the airspace would have averted this incident. As it was; by prompting me with the location of the helicopter on base; the controller in charge was able to avert any possibility of a safety issue in this situation.

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Original NASA ASRS Text

Title: BJC Controller described near conflict event involving a helicopter and an airport vehicle when they failed to note the position of the helicopter while issuing a clearance to the airport vehicle.

Narrative: An airport vehicle was conducting a field inspection with a FAA airports certification official on board and was located between the Runways on Taxiway Echo. A helicopter (Aircraft X) had just departed Runway 20 and entered the crosswind for Taxiway Delta but had not received a clearance. A Citation was inbound IFR from the northeast for Runway 11L and a North American T-6 was a northwest departure from the airport. I was focused on issuing traffic to those two aircraft just prior to the airport vehicle's request to proceed to Taxiway Golf. I instructed the vehicle to cross Runway 11R and proceed Westbound via Taxiway Delta and to hold short of Runway 11R abeam Golf (Taxiway Golf located between the parallel runways). The CIC alerted me to Aircraft X on downwind about to turn base. When Aircraft X reported base for Taxiway Delta; I changed him to Runway 11R and advised him to expect a couple patterns on Runway 11R to allow for the airfield inspection. I had not realized Aircraft X had passed beam Taxiway Echo; their downwind; when the airport vehicle had called for relocation to Taxiway Golf and thought I had time to keep the vehicle on taxiways to their requested location before Aircraft X would reach their base. Recommendation; I had been issuing traffic to a Citation inbound and a North American outbound just prior to this incident. I had taken the helicopter quite a ways out before turning their crosswind and had not relocated my strip to the Delta Taxiway header; indicating he was not yet in the pattern. I had thought the helicopter was further East on downwind when the airport vehicle requested reposition and issued those instructions. The CIC was aware of the Helicopter position and prompted me to make my landing area reassignment to the helicopter promptly to avoid a conflict. I should have located the helicopter before issuing the instructions to the vehicle or issued the new landing instructions to the helicopter before issuing the instructions to the vehicle. A better scan of my strip area and pattern to correlate the strips with what is actually going on in the airspace would have averted this incident. As it was; by prompting me with the location of the helicopter on base; the CIC was able to avert any possibility of a safety issue in this situation.

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.