Narrative:

The traffic was moderate with very high complexity due to the wind pireps and what the pilots could expect - 25 knot tailwind at 2000 ft; decreasing to 15 knots at 1500; at 900 ft. Decreasing below 10 knots; followed by a calm wind at 200 ft. I had a previous foreign airline go-around when I did not explain the wind to them. I gave it to every arrival after that. There was a pair on final; aircraft X for runway 28L; and aircraft Y for runway 28R. The spacing was great between the preceding pair and this one; so I departed two aircraft off of runways 1 in front of aircraft X and aircraft Y. Meanwhile; I tried many times to get a hold of aircraft X and local assist was calling to the arrival sector to get them as well. The arrival sector kept saying that 'they should be with you'. I kept trying by keying up and clearing them to land over and over. When they got to the threshold; the runway was clear and was prepared to watch them either land or go around. The light gun no longer hangs from the ceiling and could not be quickly accessed to utilize. Then aircraft Y keyed up and said they have to go around; too high too fast I assumed (900 ft. And 210 ground speed at about 1 1/2 mile final). I gave aircraft Y a right turn heading 310 and 3000 ft. While aircraft Y read it back; I watched aircraft X go around. As soon as they were both clear of runway 1; I departed two more aircraft. Aircraft Y was shipped to departure with the traffic advisories for the last runway 1 left departure and aircraft X going around straight out runway 28L. Then about two miles upwind; aircraft X checked in on the missed approach. I confirmed 280 heading and 3000 ft; then shipped them to departure. There was no issue with aircraft X as far as I was concerned; they were protected for the go around/published missed at all times. I am not sure why we were not in communication with aircraft X.

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Original NASA ASRS Text

Title: SFO Tower Controller reported simultaneous go-arounds; one associated with a loss of communication.

Narrative: The traffic was moderate with very high complexity due to the wind PIREPs and what the pilots could expect - 25 knot tailwind at 2000 ft; decreasing to 15 knots at 1500; at 900 ft. decreasing below 10 knots; followed by a calm wind at 200 ft. I had a previous foreign airline go-around when I did not explain the wind to them. I gave it to every arrival after that. There was a pair on final; Aircraft X for Runway 28L; and Aircraft Y for Runway 28R. The spacing was great between the preceding pair and this one; so I departed two aircraft off of Runways 1 in front of Aircraft X and Aircraft Y. Meanwhile; I tried many times to get a hold of Aircraft X and Local Assist was calling to the arrival sector to get them as well. The arrival sector kept saying that 'They should be with you'. I kept trying by keying up and clearing them to land over and over. When they got to the threshold; the runway was clear and was prepared to watch them either land or go around. The light gun no longer hangs from the ceiling and could not be quickly accessed to utilize. Then Aircraft Y keyed up and said they have to go around; too high too fast I assumed (900 ft. and 210 ground speed at about 1 1/2 mile final). I gave Aircraft Y a right turn heading 310 and 3000 ft. While Aircraft Y read it back; I watched Aircraft X go around. As soon as they were both clear of Runway 1; I departed two more aircraft. Aircraft Y was shipped to departure with the traffic advisories for the last Runway 1 Left departure and Aircraft X going around straight out Runway 28L. Then about two miles upwind; Aircraft X checked in on the missed approach. I confirmed 280 heading and 3000 ft; then shipped them to departure. There was no issue with Aircraft X as far as I was concerned; they were protected for the go around/published missed at all times. I am not sure why we were not in communication with Aircraft X.

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.