Airbus 318/319/320/321 Undifferentiated
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Communication Breakdown; Fatigue; Human-Machine Interface
ATC Issue All Types; Deviation - Speed All Types; Deviation / Discrepancy - Procedural FAR; Inflight Event / Encounter Unstabilized Approach
Flight Crew Executed Go Around / Missed Approach
Company Policy; Human Factors; Procedure
Descending on the DSNEE 4 arrival from EMLLD; we became aware of congested airport environment with two different TCAS traffic alerts very close by. Approach had us at 190 knots departing DSNEE; and we were expecting the visual to runway 20R. We had gone to flaps 2 configuration. We were handed off late to the final controller; and when we switched over we heard a company call sign with nearly identical numeric as ours; cleared for the RNAV (RNP) Z runway 20R. We heard the other aircraft read back the clearance; we knew a VERY similar call sign was on frequency. We thought we might be cleared for the same approach. We checked in and asked if we were going to get the RNAV approach; and the controller said no; we were going to get a visual unless we asked for the approach. Shortly after; the controller cleared an aircraft to descend to 3000'; but neither of us were sure that it was our call sign. The First Officer (FO) attempted to clarify; but the controller was very busy and talking nonstop. We flew a few more miles; and before we could clarify he repeated the clearance to descend to 3000' and asked if we had the airport in sight. We called the airport; and said we were high. He cleared us to fly through final approach course and intercept from the right. FO read back the clearance; and we both agreed it was going to be tight. I immediately called for gear down and got the flaps to full; I also used the speed brakes as long as safely practical. We switched over to tower control; and I made the glideslope at approx. 1400' AGL; but we were still 40kts fast. I told the FO we were going to do a 'Soft Go'. At 1000' AGL I called for 'Go Around; Takeoff/around (TOGA)' and advanced the thrust levers to TOGA. I then called 'climb' as I brought the thrust levers back to what I thought was the climb position; but was actually the Maximum Continuous Thrust (MCT) detent. The tower initially held us to 2000'; so I reduced our climb rate - we were accelerating rapidly. As we cleaned up and were cleared to 3000'; the FO recognized that we were in MCT detent and brought it to my attention. By then we were clean and rapidly approaching 250 KIAS. I brought the thrust levers back to idle as we passed 260; and we saw a maximum speed of about 280 before we began to slow down again. I selected speed mode and set 220 KIAS; positioned the thrust levers in the climb detent and re-engaged auto thrust. We slowed and turned back into a right downwind for an uneventful visual approach and landing at SNA.Causes(1)	Late clearance to descend. SNA is challenging even when on a normal profile; and a few miles made all the difference.(2)	Task saturation. The L.A basin is one of the busiest airspaces in the world. Two Traffic Alerts and nonstop chatter from the approach controller indicated that he was task saturated; as well.(3)	Call sign confusion. The scheduling shop should never have had two call signs separated by one digit arriving at the same airport at the same time.(4)	Approach expectations. We were going to do a visual; and changed our setup and expectations when we heard preceding traffic approach clearance.(5)	Fatigue. Our FAR 117 duty day limit was 10 hours. We had been awake since 3.5 hours earlier to make sign-in; and were at 9:00 of our 10:00 limit when we arrived at SNA. When we knew we were too high to likely make a successful approach; we could have asked for a vector and more time/distance to descend. Flight scheduling needs to de-conflict call signs so very similar ones are not scheduled to arrive at the same airport at the same time. The ATC controllers seemed very busy; perhaps a few more controllers on-shift would help divide the workload better. Crew scheduling could alleviate fatigue factors by avoiding sequence builds that have crews flying into airports at the back end of their duty periods that are known to present unusual challenges (even if they aren't officially 'special qualification' airports).
Airbus First officer reported a go-around caused by late clearance to descend and confusion caused by a similar call sign for an aircraft preceding them.