Tower and TRACON controllers described a conflict event from different perspectives that involved a departure and arrival operating from intersecting runways.
Synopsis
Tower and TRACON controllers described a conflict event from different perspectives that involved a departure and arrival operating from intersecting runways.
Narrative
I was working Local Control (LC) and we were on a straight XXL in and out configuration going down the East box to ZZZ. I issued 160 heading to all departures routed over ZZZ VOR off XXL. The first thing that happened was East Departure called and asked if I could work a C172 up the shoreline through my airspace; I approved this request. A few minutes later I had a couple departures and a few arrivals for XXL. I was monitoring the C172 to make sure they did not conflict with the XXL arrivals. The FLM came to me and told me that the TRACON called and advised there was an Air Carrier Y that had requested to land Runway XL. After he told me about this he no longer monitored my position. My first departure (Air Carrier X) was routed over ZZZ VOR and the Air Carrier Y was still quite a ways out so I issued a 160 heading and cleared him for take off. When he didn't answer in time I just had him hold short for the next arrival. Once the arrival had landed he was on frequency; so I put in in position and looked at the Air Carrier Y on final for XL. Now that Air Carrier Y was a little closer I knew the safest option would be to leave Air Carrier X on runway heading and let departure climb and turn him over the XL arrival. I had every intention of doing this but I still had 160 written on my strip and apparently I read it off the strip instead of listening to my brain. From this point on I don't know what happened; but I heard from the TRACON that there were still some radio communication problems on their end; but Air Carrier X was told to expedite his climb. When I was informed of the situation; Air Carrier X was well above the arrival and I believe they were able to maintain standard separation. I will use this experience in the future to be extra attentive to what I say and to stick to habits that prevent things like this from happening; such as covering the East drop tube which I almost always do but failed to this time.
Second reporter narrative
I was working the ZZZ approach East Feeder and East Departure Sectors combined. Air Carrier Y; requested Runway XL for landing. Because we were landing and departing on Runway XXL; and it would impact departing and other arriving aircraft; I asked the pilot if it was for an operational necessity. The pilot informed me it was and they did not have the numbers to land other runways. I informed the CIC of the necessity for Air Carrier Y to land Runway XL. Coordination was made with the Tower and the final sector that Air Carrier Y would be landing Runway XL and which aircraft they would be sequenced after landing the crossing runway. Air Carrier Y reported the field in sight and I cleared them for the Visual Approach to Runway XL. I instructed Air Carrier Y to contact the Tower. Air Carrier X departure strip came down the drop tube; as I was involved with other duties I placed it in my strip bay without looking at the Tower assigned heading initially. I saw Air Carrier X was turning into the arrival path of Air Carrier Y. I saw the tower had assigned them a 160 heading into the course of the arrival. I issued instructions to Air Carrier X to expedite climb through 40 to maintain 50 and instructed them to turn to a 090 heading to get them across the course of the arriving Air Carrier Y. I felt trying to stop the left turn at that point and turn back to the right would put them more into the course of the arrival and I did not have control to turn the aircraft back toward the runway they departed. When Air Carrier X departed; I was informed they called the wrong departure sector. I do not recall if they were with me at the time the initial instructions were issued. Since the rate of climb did not seem to be increasing I issued a traffic alert because it appeared separation was decreasing and may possibly decrease to less than standard separation. I reissued instructions to climb immediately through 40 and to maintain 50. The pilot acknowledged my instructions. When all traffic was no factor I turned Air Carrier X and climbed them for the rest of their normal routes. I informed the CIC that a loss of separation may have occurred.Because of ceilings; 38 BKN; I was uncertain that the departing; climbing aircraft; would be able to maintain visual separation.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.