Narrative:

I assumed position of local (7 and 1/2 hours into my shift) with all runways open and active; terminating a training session. I did not fully understand the situation of wind strength from a westerly direction -- which may have only picked up with gusts into the mid-teens during this session. When aircraft X checked in on approach to runway 11; he was sequenced as number 3 to the airport (behind traffic landing runway 22L); given the wind and landing clearance which was read back and accepted. Shortly thereafter; they asked for a wind check and subsequently advised that they were not going to be able to accept landing runway 11. He was not immediately sent around because the next runway 22L arrival was outside of teterboro at 4;000 feet. So it was expected that from this point with aircraft X seven miles west of the airport at 2;000 feet; and aircraft Y inbound for runway 22L over 13 miles apart this could be properly accommodated. I then advised cab-coordinator and cba of my intent to bring them in on a right base for runway 22L; noticing that there was no cba (class bravo transitions) traffic in the vicinity. Aircraft X was given a heading of 100 to join the right base on a visual approach (only a slight left vector in order to keep them away from teb departure airspace and guarantee his approach would keep them inside of aircraft Y). In these moments; I noted the speed of aircraft Y being well over 200 knots and that I should depart one more aircraft that was luaw (line up and wait)on runway 22R with an incorrect squawk in order to clear the parallel runway in order to offer 22R to aircraft X instead of runway 22L. Now I reached out to establish communication with aircraft Y from N90 final controller in order to exchange the traffic to the parallel runway and clear them to land runway 22L. At this point they did not report the traffic in sight when asked (just 'wilco'). All in this flurry aircraft X was given traffic for aircraft Y and instructions to change to runway 22R and did not report the traffic in sight. They (aircraft X) also advised they would have to widen out their turn to make the approach work; which was approved. At this critical moment knowing I needed the pilots to establish their own visual (in accordance with 7110.65 7-4-4) or send aircraft Y around with only 4-5 miles between them at similar altitudes; I falsely thought I had time to move onto a task that could have waited (crossing previous arrivals over runway 22R) before returning to updated traffic calls for the two subject aircraft on approach that I assumed would surely next report each other in sight. During this moment the frequency was congested and even though the two planes may have established visual separation; they were unable to advise if that was the case. Both planes reported each other in sight thereafter (once appropriate separation was lost) and landed without incident and normal operations were resumed (departing runway 22R and landing runway 22L); however; no more airplanes were brought in for runway 11 for the remainder of my time on position.in hindsight; the use of runway 11 with the tail-wind component was a bad idea that day. Also the personnel placement at the end of the shift was not handled in the most efficient manner. It could have been avoided to have me on overtime during this incident. If anything overtime; should have been given for the purposes of training on local. Numerous qualified colleagues that reported to work later were dismissed from tower duties or sent on a break prior to my relief for the shift. But without taking responsibility to a degree would be wrong. Two simple words 'go-around' could have been issued at two particular junctures avoiding this event. (1) aircraft X could have been sent around as soon as they said they could not accept the approach to runway 11; (2) aircraft Y could have been sent around as soon as they did not immediately report the aircraft X traffic in sight.

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Original NASA ASRS Text

Title: EWR Tower Controller reported a loss of separation between aircraft on parallel approaches due to congested communications and a runway assignment change.

Narrative: I assumed position of Local (7 and 1/2 hours into my shift) with all runways open and active; terminating a training session. I did not fully understand the situation of wind strength from a westerly direction -- which may have only picked up with gusts into the mid-teens during this session. When Aircraft X checked in on approach to Runway 11; he was sequenced as number 3 to the airport (behind traffic landing Runway 22L); given the wind and landing clearance which was read back and accepted. Shortly thereafter; they asked for a wind check and subsequently advised that they were not going to be able to accept landing Runway 11. He was not immediately sent around because the next Runway 22L arrival was outside of Teterboro at 4;000 feet. So it was expected that from this point with Aircraft X seven miles west of the airport at 2;000 feet; and Aircraft Y inbound for Runway 22L over 13 miles apart this could be properly accommodated. I then advised Cab-coordinator and CBA of my intent to bring them in on a right base for Runway 22L; noticing that there was no CBA (Class bravo transitions) traffic in the vicinity. Aircraft X was given a heading of 100 to join the right base on a visual approach (only a slight left vector in order to keep them away from TEB departure airspace and guarantee his approach would keep them inside of Aircraft Y). In these moments; I noted the speed of Aircraft Y being well over 200 knots and that I should depart one more aircraft that was LUAW (Line Up And Wait)on Runway 22R with an incorrect squawk in order to clear the parallel runway in order to offer 22R to Aircraft X instead of Runway 22L. Now I reached out to establish communication with Aircraft Y from N90 Final Controller in order to exchange the traffic to the parallel runway and clear them to land Runway 22L. At this point they did not report the traffic in sight when asked (just 'WILCO'). All in this flurry Aircraft X was given traffic for Aircraft Y and instructions to change to Runway 22R and did not report the traffic in sight. They (Aircraft X) also advised they would have to widen out their turn to make the approach work; which was approved. At this critical moment knowing I needed the pilots to establish their own visual (in accordance with 7110.65 7-4-4) or send Aircraft Y around with only 4-5 miles between them at similar altitudes; I falsely thought I had time to move onto a task that could have waited (crossing previous arrivals over Runway 22R) before returning to updated traffic calls for the two subject aircraft on approach that I assumed would surely next report each other in sight. During this moment the frequency was congested and even though the two planes may have established visual separation; they were unable to advise if that was the case. Both planes reported each other in sight thereafter (once appropriate separation was lost) and landed without incident and normal operations were resumed (departing Runway 22R and landing Runway 22L); however; no more airplanes were brought in for Runway 11 for the remainder of my time on position.In hindsight; the use of Runway 11 with the tail-wind component was a bad idea that day. Also the personnel placement at the end of the shift was not handled in the most efficient manner. It could have been avoided to have me on overtime during this incident. If anything overtime; should have been given for the purposes of training on Local. Numerous qualified colleagues that reported to work later were dismissed from Tower duties or sent on a break prior to my relief for the shift. But without taking responsibility to a degree would be wrong. Two simple words 'Go-Around' could have been issued at two particular junctures avoiding this event. (1) Aircraft X could have been sent around as soon as they said they could not accept the approach to Runway 11; (2) Aircraft Y could have been sent around as soon as they did not immediately report the Aircraft X traffic in sight.

Data retrieved from NASA's ASRS site 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.