Date: 201501
Local time of day: 0001-0600
Location: SFO.Airport, CA
Flight conditions: VMC
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight phase: Final Approach
Airspace: Class B SFO
ATC / advisory: TRACON NCT; Tower SFO
Second aircraft: EMB ERJ 170/175 ER/LR
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Situational Awareness
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Conflict NMAC
Detector: Automation Aircraft RA
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Procedure; Human Factors; Airport
Primary problem: Ambiguous

Narrative: While on the FMS bridge visual 28R; Approach Control issued us traffic at 9 o'clock; an Embraer RJ. We were between ARCHI and TRDOW on the visual. We told ATC that we did not have him in sight. At about 1300 feet AGL; we got a TCAS TA. It was directly under our aircraft symbol; and while hard to read; the intruder's altitude was the same as ours. A few seconds later; a TCAS RA climb was commanded and we complied and a go around was accomplished. After landing we called the Tower and they told us that the intruder; going to 28L; said he had us in sight. While it is difficult to say exactly; I feel we got within 500 feet of each other. Since we never saw him; TCAS saved the day.


Second narrative: Were cleared for the FMS bridge visual to rwy 28R. Somewhere around TRDOW intersection they called out traffic; an Embraer; at our 9 o'clock and asked if we had him in sight. I said; ''we were looking.' We further discussed amongst ourselves that we didn't see the traffic and were trying to find the traffic on the TCAS. Then they gave us a speed reduction to slow to 180 kts. Shortly thereafter we were slowed to 160 kts and told to contact tower. We switched over to tower and got a clearance to land. While descending through 1;300 ft. we both noticed that there was traffic that appeared to be beneath us and just slightly to the left. We were roughly 3-3.3 miles from the end of rwy 28R. The Captain asked me is that traffic just beneath us. I said I was just looking at that. He then said does their altitude say 1;300 ft. I said I am not sure because there was a waypoint masking the complete altitude readout. I think it said around 1;100 ft. but not sure. Immediately after that we got an RA telling us to climb. We followed the TCAS and started to climb. Then I asked the Captain if he wanted to clean up since we were no longer in a position to land. I told ATC we were climbing due to a TCAS advisory. We cleaned up to flaps 5 and 180 kts. They gave us a heading and altitude which we complied with. As we were getting our vectors back around for a new approach to rwy 28L we were trying to figure out what could have given us the RA. After an uneventful landing on 28L we requested the Towers phone number from ground control. We then called the tower before leaving the airplane. They told us it was an airplane; an Embraer; and that the Embraer had called us in sight earlier on the approach. She then said wingtip visual approaches are common on the FMS bridge visual. I have been flying into SFO for 18 yrs and have never seen anything like this.


Synopsis: B757 flight crew experiences a TCAS RA during a visual approach to Runway 28R at SFO and goes around. The traffic was on a visual to Runway 28L and had the Embraer RJ in sight.