Narrative:

I was working controller in charge (controller in charge) and monitoring a training session on LC1. Runway 11L/11R were the active runways. Traffic at the time was average volume and complexity; with 3 VFR arrivals inbound for left base to runway 11L. Aircraft X called for departure on 11L and the trainee instructed aircraft X to hold short for landing traffic. The first two arrivals were spaced closely together; and were cleared to land. Aircraft Y was the third arrival in the sequence; some distance from the first two inbounds. In order to expedite the departure of aircraft X; the ojti (on the job training instructor) informed the trainee that he wanted him to use tiph (taxi in position and hold) after the 2nd arrival. At the time; there was also traffic making a full stop from the pattern onto runway 11R (a cessna). I was watching closely to make sure the trainee got a good hold short readback from the cessna after he landed; while using tiph correctly; but I did not remember about aircraft Y also being inbound to runway 11L. It appears that the ojti also did not remember that aircraft Y was inbound. I would estimate that aircraft Y was about 5 north of bjc; perhaps still outside the airspace; when aircraft X was instructed to position and hold. Therefore; when the trainee did not remember to exchange traffic between aircraft X (in position) and aircraft Y (north of the airport) I was not aware that local made a mistake. Approximately 30 seconds elapsed; when the ojti corrected the mistake by issuing the holding traffic to aircraft Y. The trainee cleared aircraft X for takeoff; and I observed that after the aircraft was on departure roll; he cleared aircraft Y to land. Aircraft Y was no closer than 3 miles from runway threshold when aircraft X began departure roll. The scenario again is a reminder of the importance of situational awareness when tiph is used. It is critical that certified professional controllers remain vigilant about meeting the procedural requirements of tiph if they choose to use the procedure at our facility. In my opinion; one of these important requirements is that the traffic situation is not so complex as to make tiph difficult to use. While traffic complexity was routine in this situation; and did not preclude using tiph; there was still workload involved (ensuring a hold short instruction was read back correctly from a different aircraft; issuing exiting instructions to the preceding aircraft; etc.). While it is critical good readbacks are received and runway surface awareness is maintained; using tiph also requires awareness of airborne traffic picture. One way to maintain airborne traffic awareness; and avoid a tiph mistake; is to control the situation proactively; issuing information to the inbound pilot about the plan to use tiph on their runway early; as soon as the decision is that someone will be put in position on that runway. As controller in charge; I believe that part of the reason I did not catch the mistake sooner was that the next inbound aircraft to the runway was at least 5 miles from the airport; blending in with other VFR traffic north of the airport on the radar. I also believe if I was working local; I would have caught the mistake (or chosen not to use tiph at all); since part of my scan for using tiph is to check my strip bays for any inbound traffic I may have forgotten. In the future; I will try to scan the instructor and trainee strip bays more vigilantly when working as controller in charge and monitoring tiph operations.

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Original NASA ASRS Text

Title: BJC CIC controller described a potential conflict during the use of TIPH procedures when a controller and developmental both failed to remember an inbound aircraft; the reporter noting that extra vigilance is necessary during TIPH procedures.

Narrative: I was working Controller in Charge (CIC) and monitoring a training session on LC1. Runway 11L/11R were the active runways. Traffic at the time was average volume and complexity; with 3 VFR arrivals inbound for left base to Runway 11L. Aircraft X called for departure on 11L and the trainee instructed Aircraft X to hold short for landing traffic. The first two arrivals were spaced closely together; and were cleared to land. Aircraft Y was the third arrival in the sequence; some distance from the first two inbounds. In order to expedite the departure of Aircraft X; the OJTI (On the Job Training Instructor) informed the trainee that he wanted him to use TIPH (taxi in position and hold) after the 2nd arrival. At the time; there was also traffic making a full stop from the pattern onto Runway 11R (a Cessna). I was watching closely to make sure the trainee got a good hold short readback from the Cessna after he landed; while using TIPH correctly; but I did not remember about Aircraft Y also being inbound to Runway 11L. It appears that the OJTI also did not remember that Aircraft Y was inbound. I would estimate that Aircraft Y was about 5 north of BJC; perhaps still outside the airspace; when Aircraft X was instructed to position and hold. Therefore; when the trainee did not remember to exchange traffic between Aircraft X (in position) and Aircraft Y (north of the airport) I was not aware that Local made a mistake. Approximately 30 seconds elapsed; when the OJTI corrected the mistake by issuing the holding traffic to Aircraft Y. The trainee cleared Aircraft X for takeoff; and I observed that after the aircraft was on departure roll; he cleared Aircraft Y to land. Aircraft Y was no closer than 3 miles from runway threshold when Aircraft X began departure roll. The scenario again is a reminder of the importance of situational awareness when TIPH is used. It is critical that Certified Professional Controllers remain vigilant about meeting the procedural requirements of TIPH if they choose to use the procedure at our facility. In my opinion; one of these important requirements is that the traffic situation is not so complex as to make TIPH difficult to use. While traffic complexity was routine in this situation; and did not preclude using TIPH; there was still workload involved (ensuring a hold short instruction was read back correctly from a different aircraft; issuing exiting instructions to the preceding aircraft; etc.). While it is critical good readbacks are received and runway surface awareness is maintained; using TIPH also requires awareness of airborne traffic picture. One way to maintain airborne traffic awareness; and avoid a TIPH mistake; is to control the situation proactively; issuing information to the inbound pilot about the plan to use TIPH on their runway early; as soon as the decision is that someone will be put in position on that runway. As CIC; I believe that part of the reason I did not catch the mistake sooner was that the next inbound aircraft to the runway was at least 5 miles from the airport; blending in with other VFR traffic north of the airport on the RADAR. I also believe if I was working Local; I would have caught the mistake (or chosen not to use TIPH at all); since part of my scan for using TIPH is to check my strip bays for any inbound traffic I may have forgotten. In the future; I will try to scan the instructor and trainee strip bays more vigilantly when working as CIC and monitoring TIPH operations.

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.